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lintcode题解

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目录

index title code Difficulty
1 A + B Problem JavaScript Naive
2 Trailing Zeroes JavaScript Easy
3 Digit Counts Easy
4 Ugly Number II JavaScript Medium
5 Kth Largest Element Medium
6 Merge Two Sorted Arrays JavaScript Easy
7 Serialize and Deserialize Binary Tree Python Medium
8 Rotate Character Array Python Easy
9 Fizz Buzz JavaScript Easy
10 String Permutation II Medium
11 Search Range in Binary Search Tree Python Medium
12 Min Stack Python Medium
13 Implement strStr() TypeScript Naive
14 First Position of Target JavaScript Easy
15 Permutations Python Medium
16 Permutations II Python Medium
17 Subsets Python Medium
18 Subsets II Python Medium
20 Dices Sum Python Medium
21 Moving Circle Medium
22 Flatten List Python Naive
23 Is alphanumeric TypeScript Naive
24 LFU Cache Python Hard
25 Print X TypeScript Naive
26 inner product Hard
27 abc String Hard
28 Search a 2D Matrix JavaScript Easy
29 Interleaving String Hard
30 Insert Interval Medium
31 Partition Array TypeScript Medium
32 Minimum Window Substring Python Medium
33 N-Queens Medium
34 N-Queens II Medium
35 Reverse Linked List JavaScript TypeScript Easy
36 Reverse Linked List II JavaScript TypeScript Medium
37 Reverse 3-digit Integer JavaScript Naive
38 Search a 2D Matrix II JavaScript Medium
39 Recover Rotated Sorted Array JavaScript Easy
40 Implement Queue by Two Stacks Python Medium
41 Maximum Subarray JavaScript TypeScript Easy
42 Maximum Subarray II Python Medium
43 Maximum Subarray III JavaScript Hard
44 Minimum Subarray Python Easy
45 Maximum Subarray Difference JavaScript Medium
46 Majority Element Python Easy
47 Majority Element II Python Medium
48 Majority Number III JavaScript Medium
49 Sort Letters by Case Python Medium
50 Product of Array Exclude Itself Python Easy
51 Previous Permutation Medium
52 Next Permutation Medium
53 Reverse Words in a String Python Easy
54 String to Integer (atoi) Hard
55 Compare Strings JavaScript TypeScript Easy
56 Two Sum JavaScript Easy
57 3Sum Python Medium
58 4Sum JavaScript Python Medium
59 3Sum Closest JavaScript Medium
60 Search Insert Position JavaScript TypeScript Easy
61 Search for a Range JavaScript Medium
62 Search in Rotated Sorted Array JavaScript Medium
63 Search in Rotated Sorted Array II JavaScript Medium
64 Merge Sorted Array (easy version) Python Easy
65 Median of two Sorted Arrays Hard
66 Binary Tree Preorder Traversal JavaScript Easy
67 Binary Tree Inorder Traversal JavaScript TypeScript Easy
68 Binary Tree Postorder Traversal JavaScript TypeScript Easy
69 Binary Tree Level Order Traversal JavaScript TypeScript Easy
70 Binary Tree Level Order Traversal II Python Medium
71 Binary Tree Zigzag Level Order Traversal JavaScript TypeScript Medium
72 Construct Binary Tree from Inorder and Postorder Traversal JavaScript Medium
73 Construct Binary Tree from Preorder and Inorder Traversal JavaScript Medium
74 First Bad Version Python Medium
75 Find Peak Element Python Medium
76 Longest Increasing Subsequence JavaScript Medium
77 Longest Common Subsequence JavaScript Medium
78 Longest Common Prefix TypeScript Medium
79 Longest Common Substring JavaScript Medium
80 Median TypeScript Easy
81 Find Median from Data Stream Hard
82 Single Number JavaScript Easy
83 Single Number II JavaScript TypeScript Medium
84 Single Number III Python Medium
85 Insert Node in a Binary Search Tree Python Easy
86 Binary Search Tree Iterator Python Hard
87 Remove Node in Binary Search Tree Python Hard
88 Lowest Common Ancestor of a Binary Tree Python Medium
89 k Sum Hard
90 k Sum II Python Medium
91 Minimum Adjustment Cost Medium
92 Backpack JavaScript TypeScript Medium
93 Balanced Binary Tree JavaScript TypeScript Easy
94 Binary Tree Maximum Path Sum JavaScript TypeScript Medium
95 Validate Binary Search Tree JavaScript Medium
96 Partition List JavaScript TypeScript Easy
97 Maximum Depth of Binary Tree JavaScript TypeScript Easy
98 Sort List Python Medium
99 Reorder List Python Medium
100 Remove Duplicates from Sorted Array Python Easy
101 Remove Duplicates from Sorted Array II Python Easy
102 Linked List Cycle Python Medium
103 Linked List Cycle II Python Hard
104 Merge K Sorted Lists Python Medium
105 Copy List with Random Pointer Python Medium
106 Convert Sorted List to Binary Search Tree Python Medium
107 Word Break Medium
108 Palindrome Partitioning II Medium
109 Triangle JavaScript Medium
110 Minimum Path Sum JavaScript Easy
111 Climbing Stairs JavaScript Easy
112 Remove Duplicates from Sorted List JavaScript Easy
113 Remove Duplicates from Sorted List II Python Medium
114 Unique Paths JavaScript Easy
115 Unique Paths II JavaScript Easy
116 Jump Game JavaScript Medium
117 Jump Game II JavaScript Medium
118 Distinct Subsequences Python Medium
119 Edit Distance Medium
120 Word Ladder Hard
121 Word Ladder II Hard
122 Largest Rectangle in Histogram Hard
123 Word Search TypeScript Medium
124 Longest Consecutive Sequence TypeScript Medium
125 Backpack II JavaScript Medium
126 Max Tree Hard
127 Topological Sorting Medium
128 Hash Function JavaScript Easy
129 Rehashing Medium
130 Heapify Python Medium
131 The Skyline Problem Super
132 Word Search II Hard
133 Longest Word Python Easy
134 LRU Cache Python Hard
135 Combination Sum Python Medium
136 Palindrome Partitioning Medium
137 Clone Graph Medium
138 Subarray Sum Python Easy
139 Subarray Sum Closest Medium
140 Fast Power Python Medium
141 Sqrt(x) Python Easy
142 O(1) Check Power of 2 JavaScript Easy
143 Sort Colors II TypeScript Medium
144 Interleaving Positive and Negative Numbers Python Medium
145 Lowercase to Uppercase JavaScript Naive
146 Lowercase to Uppercase II TypeScript Naive
147 Narcissistic Number Easy
148 Sort Colors TypeScript Medium
149 Best Time to Buy and Sell Stock JavaScript Medium
150 Best Time to Buy and Sell Stock II JavaScript Medium
151 Best Time to Buy and Sell Stock III JavaScript Medium
152 Combinations Python Medium
153 Combination Sum II Python Medium
154 Regular Expression Matching Hard
155 Minimum Depth of Binary Tree JavaScript Easy
156 Merge Intervals TypeScript Easy
157 Unique Characters Python Easy
158 Valid Anagram JavaScript Easy
159 Find Minimum in Rotated Sorted Array JavaScript Medium
160 Find Minimum in Rotated Sorted Array II JavaScript Medium
161 Rotate Image JavaScript Medium
162 Set Matrix Zeroes JavaScript Medium
163 Unique Binary Search Trees JavaScript Medium
165 Merge Two Sorted Lists JavaScript Easy
166 Nth to Last Node in List Python Easy
167 Add Two Numbers JavaScript Easy
168 Burst Balloons Hard
169 Tower of Hanoi Medium
170 Rotate List JavaScript Medium
171 Anagrams JavaScript Medium
172 Remove Element Python Easy
173 Insertion Sort List Python Easy
174 Remove Nth Node From End of List JavaScript Easy
175 Invert Binary Tree JavaScript Easy
176 Route Between Two Nodes in Graph Medium
177 Convert Sorted Array to Binary Search Tree With Minimal Height. Python Easy
178 Graph Valid Tree Medium
179 Update Bits TypeScript Medium
180 Binary Representation Hard
181 Flip Bits JavaScript Easy
182 Delete Digits Medium
183 Wood Cut TypeScript Hard
184 Largest Number Medium
185 Matrix Zigzag Traversal JavaScript Easy
186 Max Points on a Line Medium
187 Gas Station Medium
188 Insert five TypeScript Easy
189 First Missing Positive JavaScript Medium
191 Maximum Product Subarray JavaScript Medium
192 Wildcard Matching Hard
193 Longest Valid Parentheses JavaScript Medium
194 Find Words TypeScript Medium
196 Missing Number JavaScript Easy
197 Permutation Index Medium
198 Permutation Index II Medium
199 Judge Connection Medium
200 Longest Palindromic Substring Medium
201 Segment Tree Build Python Medium
202 Segment Tree Query Python Medium
203 Segment Tree Modify Python Medium
204 Singleton Python Easy
205 Interval Minimum Number Python Medium
206 Interval Sum Python Medium
207 Interval Sum II Python Hard
208 Assignment Operator Overloading (C++ Only) Medium
209 First Unique Character in a String JavaScript Easy
210 Null-terminated String Easy
211 String Permutation JavaScript Easy
212 Space Replacement Python Easy
213 String Compression JavaScript Easy
214 Max of Array TypeScript Naive
215 Rate Limiter Hard
216 Substring Rotation Easy
217 Remove Duplicates from Unsorted List Easy
218 Student Level Easy
219 Insert Node in Sorted Linked List Easy
220 Hail conjecture Easy
221 Add Two Numbers II JavaScript Medium
222 Setter and Getter Naive
223 Palindrome Linked List JavaScript Medium
224 Implement Three Stacks by Single Array Medium
225 Find Node in Linked List Naive
226 Set of Stacks II Hard
227 Mock Hanoi Tower by Stacks Easy
228 Middle of Linked List Naive
229 Stack Sorting Medium
230 Animal Shelter Hard
231 Typeahead Hard
232 Tiny Url Medium
233 Next Smaller and Larger Number with the Same 1 Bits Medium
234 Web Crawler Super
235 Prime Factorization Easy
236 Swap Bits Easy
237 Missing Integer Easy
238 Monochrome Screen Easy
239 Root of Equation Easy
240 Program Check Hard
241 String to Integer Naive
242 Convert Binary Tree to Linked Lists by Depth Python Easy
243 Amicable Pair Easy
244 Delete Char Medium
245 Subtree Medium
246 Binary Tree Path Sum II Medium
247 Segment Tree Query II Python Medium
248 Count of Smaller Number JavaScript TypeScript Medium
249 Count of Smaller Number before itself JavaScript Hard
250 Special Palindrome String TypeScript Easy
251 Array compression Medium
252 arithmetic matrix Medium
253 URL Edcode TypeScript Easy
254 Drop Eggs Easy
255 Multi-string search TypeScript Easy
256 The Maximum Order Hard
257 Longest String Chain Medium
258 Map Jump Hard
259 Find the largest Divisor TypeScript Medium
260 Same Diagonal Elements TypeScript Easy
261 Maximum Connected Area Medium
262 heir tree Medium
263 Matching of parentheses TypeScript Easy
264 Counting Universal Subarrays Easy
265 Maximum Non-Negative Subarray TypeScript Easy
266 Expect Distance Medium
267 minimum rest days Medium
268 Parentheses Score TypeScript Medium
269 two colors' tower Hard
270 Letter Combinations of a Phone Number II Medium
271 prefix notation to postfix notation Medium
272 Climbing Stairs II Easy
273 Test Strategy Medium
274 Make binary tree average Super
275 Moving Shed Medium
276 another zuma TypeScript Medium
277 Word Spacing Easy
278 Paint Fill JavaScript Medium
279 Number of Ways to Represent N Cents Medium
280 Closest City TypeScript Easy
281 Paint the Ceiling Medium
282 Decrypt the String TypeScript Easy
283 Max of 3 Numbers JavaScript Naive
285 Tall Building TypeScript Medium
286 Inversions Hard
287 The Competition of View Medium
288 Container Design Python Easy
289 Container Design II Python Easy
290 Sorted Arrangement Hard
291 Second Diameter Medium
292 Sort Anagrams Array Easy
293 The depth of the tunnel Medium
294 Linked List Simplification TypeScript Easy
295 Intersection TypeScript Easy
296 Unique Array Easy
297 Find the maximum TypeScript Naive
298 Find prime TypeScript Naive
299 Typing practising Easy
300 Meeting Room IV Medium
301 Lucky Number II Hard
302 Digital Pairing Easy
303 Beautiful Number Medium
304 Maximum product TypeScript Medium
305 longest increasing path in a matrix Hard
306 Product List TypeScript Easy
307 Transform String Medium
308 Special Substring Medium
309 Interleaved Array TypeScript Easy
310 Digital distortion Easy
311 Pioneering palindrome TypeScript Easy
312 Bull Cards Medium
313 Minimum Insertion Hard
314 The Lost Record Medium
315 Reformat String TypeScript Medium
316 Combination set TypeScript Medium
317 Minimum Parentheses Matching Medium
318 Character Grid TypeScript Easy
319 Square Queue Hard
321 perfect string Easy
322 Chess Game Easy
323 string game Hard
325 Football Hard
326 Slide Soduku Easy
327 Distance Metrics TypeScript Medium
328 String Partition Medium
329 Double Array Easy
330 Increasing Number Medium
331 Confusing Number Medium
332 restoreArray Hard
333 Identifying Strings Medium
334 Order Check TypeScript Easy
335 plateau Medium
336 Text Compression Easy
337 Team notification Medium
339 Median II Medium
340 Red and Black Chess Hard
342 Valley sequence Medium
343 Circle Easy
344 Song Time Hard
345 the sum of array Easy
346 xorsum of Interval extremum Hard
347 maximum number expectation Hard
348 TrackSwitching TypeScript Medium
349 Developer-Tester Integration Hard
350 Slash Separating Hard
351 External Sorting Practising Easy
352 PrettyPrint Easy
353 Largest letter TypeScript Easy
354 lottery draw Hard
355 shuttleInBuildings Hard
357 Symmetrical Suffix Medium
358 treePlanning TypeScript Easy
359 makeEquilateralTriangle TypeScript Easy
360 Sliding Window Median Hard
362 Sliding Window Maximum JavaScript Hard
363 Trapping Rain Water Medium
364 Trapping Rain Water II Hard
365 Count 1 in Binary Python Easy
366 Fibonacci JavaScript Naive
367 Expression Tree Build Hard
368 Expression Evaluation Hard
369 Convert Expression to Polish Notation Medium
370 Convert Expression to Reverse Polish Notation Medium
371 Print Numbers by Recursion JavaScript Medium
372 Delete Node in a Linked List Python Easy
373 Partition Array by Odd and Even Python Easy
374 Spiral Matrix JavaScript Medium
375 Clone Binary Tree JavaScript Medium
376 Binary Tree Path Sum Python Easy
378 Convert Binary Tree to Doubly Linked List Python Medium
379 Reorder array to construct the minimum number Medium
380 Intersection of Two Linked Lists Python Medium
381 Spiral Matrix II Medium
382 Triangle Count Medium
383 Container With Most Water Medium
384 Longest Substring Without Repeating Characters JavaScript Medium
385 ArrayList Easy
386 Longest Substring with At Most K Distinct Characters Medium
387 The Smallest Difference JavaScript Medium
388 Permutation Sequence Medium
389 Valid Sudoku TypeScript Easy
390 Find Peak Element II Hard
391 Number of Airplanes in the Sky Medium
392 House Robber JavaScript Medium
393 Best Time to Buy and Sell Stock IV JavaScript Medium
394 Coins in a Line Medium
395 Coins in a Line II Medium
396 Coins in a Line III Hard
397 Longest Continuous Increasing Subsequence JavaScript Easy
398 Longest Ascent Path Hard
400 Maximum Gap TypeScript Medium
401 Kth Smallest Number in Sorted Matrix JavaScript Medium
402 Continuous Subarray Sum JavaScript Medium
403 Continuous Subarray Sum II Medium
404 Subarray Sum II Medium
405 Submatrix Sum Medium
406 Minimum Size Subarray Sum JavaScript Medium
407 Plus One JavaScript Easy
408 Add Binary JavaScript Easy
411 Gray Code TypeScript Medium
412 Candy Medium
413 Reverse Integer JavaScript Easy
414 Divide Two Integers TypeScript Medium
415 Valid Palindrome JavaScript Medium
417 Valid Number TypeScript Easy
418 Integer to Roman JavaScript Medium
419 Roman to Integer JavaScript Medium
420 Count and Say Easy
421 Simplify Path TypeScript Medium
422 Length of Last Word JavaScript Easy
423 Valid Parentheses JavaScript Easy
424 Evaluate Reverse Polish Notation Python Medium
425 Letter Combinations of a Phone Number JavaScript Medium
426 Restore IP Addresses JavaScript Medium
427 Generate Parentheses JavaScript Medium
428 Pow(x, n) Python Medium
430 Scramble String Hard
431 Connected Component in Undirected Graph Medium
432 Find the Weak Connected Component in the Directed Graph Medium
433 Number of Islands JavaScript Easy
434 Number of Islands II Medium
435 Post Office Problem Hard
436 Maximal Square JavaScript Medium
437 Copy Books Medium
438 Copy Books II Hard
439 Segment Tree Build II Python Medium
440 Backpack III Medium
442 Implement Trie Python Medium
443 Two Sum - Greater than target Medium
444 graph valid tree II Medium
445 Cosine Similarity Python Easy
447 Search in a Big Sorted Array Medium
448 Inorder Successor in BST Python Medium
449 Char to Integer Naive
450 Reverse Nodes in k-Group JavaScript Hard
451 Swap Nodes in Pairs JavaScript Easy
452 Remove Linked List Elements JavaScript Easy
453 Flatten Binary Tree to Linked List JavaScript Easy
454 Rectangle Area Python Naive
455 Student ID Easy
456 Reference Naive
457 Classical Binary Search Python Easy
458 Last Position of Target Easy
459 Closest Number in Sorted Array Easy
460 Find K Closest Elements JavaScript Medium
461 Kth Smallest Numbers in Unsorted Array Medium
462 Total Occurrence of Target Easy
463 Sort Integers JavaScript Naive
464 Sort Integers II JavaScript Easy
465 Kth Smallest Sum In Two Sorted Arrays Hard
466 Count Linked List Nodes JavaScript Naive
467 Complete Binary Tree Easy
468 Symmetric Binary Tree Easy
469 Same Tree JavaScript Easy
470 Tweaked Identical Binary Tree Easy
471 Top K Frequent Words JavaScript Medium
472 Binary Tree Path Sum III Hard
473 Add and Search Word - Data structure design Medium
474 Lowest Common Ancestor II Python Easy
475 Binary Tree Maximum Path Sum II Medium
476 Stone Game JavaScript Medium
477 Surrounded Regions Python Medium
478 Simple Calculator TypeScript Naive
479 Second Max of Array JavaScript Easy
480 Binary Tree Paths JavaScript Easy
481 Binary Tree Leaf Sum Easy
482 Binary Tree Level Sum Easy
483 Convert Linked List to Array List Naive
484 Swap Two Integers in Array JavaScript Naive
485 Generate ArrayList with Given Size Naive
486 Merge K Sorted Arrays JavaScript Medium
487 Name Deduplication Easy
488 Happy Number JavaScript Easy
489 Convert Array List to Linked List Easy
490 Set of Stacks Easy
491 Palindrome Number JavaScript Easy
492 Implement Queue by Linked List Python Easy
493 Implement Queue by Linked List II Easy
494 Implement Stack by Two Queues Easy
495 Implement Stack Python Easy
496 Toy Factory Python Easy
497 Shape Factory Easy
498 Parking Lot Hard
499 Word Count (Map Reduce) Medium
500 Inverted Index Medium
501 Design Twitter Medium
502 Mini Cassandra Medium
503 Anagram (Map Reduce) Medium
504 Inverted Index (Map Reduce) Medium
505 Web Logger Medium
506 Movie Recommendation Medium
507 Wiggle Sort II Hard
508 Wiggle Sort Medium
509 Mini Yelp Hard
510 Maximal Rectangle Hard
511 Swap Two Nodes in Linked List JavaScript Medium
512 Decode Ways JavaScript Medium
513 Perfect Squares JavaScript Medium
514 Paint Fence TypeScript Easy
515 Paint House TypeScript Medium
516 Paint House II TypeScript Hard
517 Ugly Number JavaScript Easy
518 Super Ugly Number JavaScript Medium
519 Consistent Hashing Easy
520 Consistent Hashing II Medium
521 Remove Duplicate Numbers in Array Easy
522 Tiny Url II Medium
523 Url Parser Medium
524 Left Pad Python Easy
525 Mini Uber Medium
526 Load Balancer Medium
527 Trie Serialization Hard
528 Flatten Nested List Iterator Python Medium
529 Geohash Medium
530 Geohash II Medium
531 Six Degrees Medium
532 Reverse Pairs JavaScript Medium
533 Two Sum - Closest to target Medium
534 House Robber II JavaScript Medium
535 House Robber III Medium
537 N-Gram (Map Reduce) Medium
538 Memcache Medium
539 Move Zeroes JavaScript Easy
540 Zigzag Iterator Python Medium
541 Zigzag Iterator II Medium
543 Kth Largest in N Arrays Hard
544 Top k Largest Numbers Medium
545 Top k Largest Numbers II Medium
546 Implement Queue by Interface Easy
547 Intersection of Two Arrays Python Easy
548 Intersection of Two Arrays II JavaScript Easy
549 Top K Frequent Words (Map Reduce) Medium
550 Top K Frequent Words II Hard
551 Nested List Weight Sum Python Easy
552 Create Maximum Number Hard
553 Bomb Enemy Medium
554 Sort Integers (Map Reduce) Medium
555 Counting Bloom Filter Python Medium
556 Standard Bloom Filter Python Medium
557 Count Characters Easy
558 Sliding Window Matrix Maximum Medium
559 Trie Service Medium
560 Friendship Service Easy
561 Array Distance Hard
562 Backpack IV JavaScript Medium
563 Backpack V JavaScript Medium
564 Combination Sum IV JavaScript Medium
565 Heart Beat Medium
566 GFS Client Medium
567 maximum score TypeScript Medium
568 Three Chances Medium
569 Add Digits JavaScript Easy
570 Find the Missing Number II Medium
571 Judgment repetition TypeScript Medium
572 Music Pairs TypeScript Easy
573 Build Post Office II Hard
574 Build Post Office Medium
575 Decode String TypeScript Medium
576 Split Array TypeScript Medium
577 Merge K Sorted Interval Lists Medium
578 Lowest Common Ancestor III Python Medium
581 Longest Repeating Subsequence Medium
582 Word Break II Hard
584 Drop Eggs II Medium
585 Maximum Number in Mountain Sequence JavaScript Medium
586 Sqrt(x) II Medium
587 Two Sum - Unique pairs Medium
588 Partition Equal Subset Sum JavaScript Medium
589 Connecting Graph Medium
590 Connecting Graph II Medium
591 Connecting Graph III Medium
593 Stone Game II Medium
594 strStr II Hard
595 Binary Tree Longest Consecutive Sequence JavaScript Easy
596 Minimum Subtree Easy
597 Subtree with Maximum Average Easy
598 Zombie in Matrix Medium
600 Smallest Rectangle Enclosing Black Pixels Hard
601 Flatten 2D Vector Python Medium
602 Russian Doll Envelopes Hard
603 Largest Divisible Subset Medium
604 Window Sum JavaScript Easy
605 Sequence Reconstruction Medium
606 Kth Largest Element II Medium
607 Two Sum III - Data structure design Python Easy
608 Two Sum II - Input array is sorted JavaScript Medium
609 Two Sum - Less than or equal to target TypeScript Medium
610 Two Sum - Difference equals to target Medium
611 Knight Shortest Path Medium
612 K Closest Points Medium
613 High Five Medium
614 Binary Tree Longest Consecutive Sequence II JavaScript Medium
615 Course Schedule Medium
616 Course Schedule II Medium
617 Maximum Average Subarray II Medium
618 Search Graph Nodes Medium
619 Binary Tree Longest Consecutive Sequence III Medium
620 Maximum Subarray IV Medium
621 Maximum Subarray V Hard
622 Frog Jump Hard
623 K Edit Distance Hard
624 Remove Substrings Medium
625 Partition Array II Medium
626 Rectangle Overlap Easy
627 Longest Palindrome JavaScript Easy
628 Maximum Subtree Easy
629 Minimum Spanning Tree Hard
630 Knight Shortest Path II Medium
631 Maximal Square II Medium
632 Binary Tree Maximum Node Python Easy
633 Find the Duplicate Number JavaScript Hard
634 Word Squares Hard
635 Boggle Game Hard
636 132 Pattern Medium
637 Valid Word Abbreviation JavaScript Easy
638 Isomorphic Strings JavaScript Easy
639 Word Abbreviation Hard
640 One Edit Distance Medium
641 Missing Ranges TypeScript Medium
642 Moving Average from Data Stream Python Easy
643 Longest Absolute File Path Medium
644 Strobogrammatic Number JavaScript Easy
645 Find the Celebrity Medium
646 First Position Unique Character JavaScript Easy
647 Find All Anagrams in a String JavaScript Medium
648 Unique Word Abbreviation Python Medium
649 Binary Tree Upside Down JavaScript Medium
650 Find Leaves of Binary Tree Python Medium
651 Binary Tree Vertical Order Traversal JavaScript Medium
652 Factorization Medium
653 Expression Add Operators Hard
654 Sparse Matrix Multiplication Medium
655 Add Strings JavaScript Easy
656 Multiply Strings Medium
657 Insert Delete GetRandom O(1) Medium
658 Swap Without Extra Variable (Only C++) Easy
659 Encode and Decode Strings Python Medium
660 Read N Characters Given Read4 II - Call multiple times Hard
661 Convert BST to Greater Tree JavaScript Easy
662 Guess Number Higher or Lower Python Easy
663 Walls and Gates Medium
664 Counting Bits JavaScript Medium
665 Range Sum Query 2D - Immutable Python Medium
666 Guess Number Higher or Lower II Medium
667 Longest Palindromic Subsequence Medium
668 Ones and Zeroes Medium
669 Coin Change JavaScript Medium
671 Rotate Words Python Easy
676 Decode Ways II Hard
677 Number of Big Islands TypeScript Medium
678 Shortest Palindrome Medium
679 Unique Paths III Hard
680 Split String Python Medium
681 First Missing Prime Number Medium
683 Word Break III Medium
684 Missing String JavaScript Easy
685 First Unique Number in Data Stream JavaScript Medium
686 Remove Arbitrary Space JavaScript Easy
688 The Number In Words Medium
689 Two Sum IV - Input is a BST Python Medium
690 Factorial Hard
691 Recover Binary Search Tree JavaScript Medium
692 Sliding Window Unique Elements Sum JavaScript Medium
693 Remove Digits Medium
696 Course Schedule III Hard
697 Sum of Square Numbers JavaScript Easy
698 Maximum Distance in Arrays Medium
699 Check Sum of K Primes Hard
700 Cutting a Rod JavaScript Medium
701 Trim a Binary Search Tree JavaScript Medium
702 Concatenated String with Uncommon Characters of Two Strings JavaScript Easy
703 Folding Array Hard
704 Bulb Switcher II Medium
706 Binary Watch TypeScript Medium
707 Optimal Account Balancing Super
708 Elevator system - OO Design Hard
709 Restaurant OO Design Hard
712 Vending machine OO Design Hard
714 Black Jack OO Design Medium
716 Add and Search TypeScript Easy
717 Tree Longest Path With Same Value Medium
718 Repeat String Medium
719 Calculate Maximum Value Medium
720 Rearrange a String With Integers JavaScript Easy
721 Next Sparse Number Hard
722 Maximum Subarray VI Super
723 Rotate Bits - Left TypeScript Medium
724 Minimum Partition Medium
725 Boolean Parenthesization Hard
726 Check Full Binary Tree JavaScript Medium
727 Chinese Remainder Theorem Hard
728 Three Distinct Factors TypeScript Medium
729 Last Digit By Factorial Divide Medium
730 Sum of All Subsets JavaScript Easy
731 Restaurant II OO Design Hard
732 Hotel II OO Design Hard
734 Number of Subsequences of Form a^i b^j c^k Medium
735 Replace With Greatest From Right Python Medium
737 Find Elements in Matrix JavaScript Easy
738 Count Different Palindromic Subsequences Hard
739 24 Game Hard
740 Coin Change 2 JavaScript Medium
741 Calculate Maximum Value II Medium
742 Self Dividing Numbers Medium
743 Monotone Increasing Digits Medium
744 Sum of first K even-length Palindrome numbers Medium
745 Palindromic Ranges Medium
746 Design Tic-Tac-Toe Hard
747 Coffee Maker OO Design Medium
748 Kindle OO Design Medium
749 John's backyard garden JavaScript Easy
750 Portal Medium
751 John's business Medium
752 Rogue Knight Sven Medium
756 Multiply Two Numbers JavaScript Easy
757 Shortest Unordered Array TypeScript Easy
759 Time Angle JavaScript Easy
760 Binary Tree Right Side View JavaScript Medium
761 Smallest Subset JavaScript Medium
762 Longest Common Subsequence II Hard
763 Hex Conversion JavaScript Easy
764 Calculate Circumference And Area Python Easy
765 Valid Triangle JavaScript Easy
766 Leap Year JavaScript Easy
767 Reverse Array JavaScript Easy
768 Yang Hui Triangle JavaScript Easy
770 Maximum and Minimum JavaScript Easy
771 Double Factorial Easy
772 Group Anagrams Medium
773 Valid Anagrams JavaScript Easy
774 Repeated DNA JavaScript Medium
775 Palindrome Pairs Hard
776 Strobogrammatic Number II TypeScript Medium
777 Valid Perfect Square JavaScript Easy
778 Pacific Atlantic Water Flow Python Medium
779 Generalized Abbreviation TypeScript Medium
780 Remove Invalid Parentheses Hard
782 AND and OR TypeScript Medium
783 Minimum Risk Path Hard
784 The Longest Common Prefix II Easy
785 Maximum Weighted Sum Path JavaScript Medium
786 Linked List Weighted Sum In Reverse Order Easy
787 The Maze Medium
788 The Maze II Medium
789 The Maze III Hard
790 Parser Medium
791 Merge Number JavaScript Medium
792 Kth Prime Number TypeScript Easy
793 Intersection of Arrays Medium
794 Sliding Puzzle II Hard
795 4-Way Unique Paths Medium
796 Open the Lock Hard
797 Reach a Number Easy
798 Backpack VII Medium
799 Backpack VIII Medium
800 Backpack IX JavaScript Medium
801 Backpack X Medium
802 Sudoku Solver Hard
803 Shortest Distance from All Buildings Hard
804 Number of Distinct Islands II Hard
805 Maximum Association Set Medium
806 Buy Fruits Medium
807 Palindrome Number II Easy
808 Movie Network Medium
809 K-th Symbol in Grammar Medium
810 Swim in Rising Water Hard
811 Swap Adjacent in LR String Medium
812 Bold Words in String TypeScript Easy
813 Find Anagram Mappings JavaScript Easy
814 Shortest Path in Undirected Graph Medium
815 Course Schedule IV Hard
816 Traveling Salesman Problem Hard
817 Range Sum Query 2D - Mutable Medium
818 Subset With Target Hard
819 Word Sorting Medium
820 Rectangle Medium
821 Time Intersection Medium
822 Reverse Order Storage JavaScript Easy
823 Input Stream JavaScript Easy
824 Single Number IV JavaScript Medium
825 Bus Station Hard
826 Computer Maintenance Hard
828 Word Pattern JavaScript Easy
829 Word Pattern II Hard
830 String Sort Easy
831 3Sum II Medium
832 Count Negative Number Medium
833 Process Sequence Medium
834 Remove Duplicate Letters JavaScript Medium
835 Hamming Distance JavaScript TypeScript Easy
836 Partition to K Equal Sum Subsets Hard
837 Palindromic Substrings JavaScript Medium
838 Subarray Sum Equals K JavaScript Easy
839 Merge Two Sorted Interval Lists TypeScript Easy
840 Range Sum Query - Mutable Python Medium
841 String Replace Hard
842 Origami Medium
843 Digital Flip JavaScript Medium
844 Number Pair Statistics Easy
845 Greatest Common Divisor JavaScript Easy
846 Multi-keyword Sort JavaScript Easy
847 Split BST Medium
848 Minimize Max Distance to Gas Station Hard
849 Basic Calculator III Hard
850 Employee Free Time Hard
851 Pour Water Medium
852 IP to CIDR Easy
853 Number Of Corner Rectangles Medium
854 Closest Leaf in a Binary Tree JavaScript Medium
855 Sentence Similarity II Medium
856 Sentence Similarity JavaScript Easy
857 Minimum Window Subsequence Hard
858 Candy Crush Medium
859 Max Stack Python Hard
860 Number of Distinct Islands Medium
861 K Empty Slots Hard
862 Next Closest Time TypeScript Medium
863 Binary Tree Path Sum IV TypeScript Medium
864 Equal Tree Partition JavaScript Medium
865 Remove 9 Hard
866 Coin Path Hard
867 4 Keys Keyboard Medium
868 Maximum Average Subarray JavaScript Easy
869 Find the Derangement of An Array Medium
871 Minimum Factorization Medium
872 Kill Process Python Medium
873 Squirrel Simulation Medium
874 Maximum Vacation Days Hard
875 Longest Line of Consecutive One in Matrix JavaScript Medium
876 Split Concatenated Strings Medium
877 Split Array with Equal Sum Medium
878 Boundary of Binary Tree Medium
879 Output Contest Matches Medium
880 Construct Binary Tree from String JavaScript Medium
881 Lonely Pixel II Medium
882 Lonely Pixel TypeScript Medium
883 Max Consecutive Ones II JavaScript Medium
884 Find Permutation Medium
885 Encode String with Shortest Length Hard
886 Convex Polygon Medium
887 Ternary Expression Parser Medium
888 Valid Word Square JavaScript Easy
889 Sentence Screen Fitting Medium
890 Minimum Unique Word Abbreviation Hard
891 Valid Palindrome II JavaScript Medium
892 Alien Dictionary JavaScript Hard
893 Longest Palindromic Substring II Hard
894 Pancake Sorting Medium
895 Friend Request Easy
896 Prime Product Medium
897 Island City Medium
898 Leftmost One Medium
900 Closest Binary Search Tree Value JavaScript Easy
901 Closest Binary Search Tree Value II Hard
902 Kth Smallest Element in a BST JavaScript Medium
903 Range Addition TypeScript Medium
904 Plus One Linked List JavaScript Medium
905 Nested List Weight Sum II Medium
906 Sort Transformed Array JavaScript Medium
907 Rearrange String k Distance Apart Hard
908 Line Reflection JavaScript Medium
909 Android Unlock Patterns Medium
910 Largest BST Subtree Medium
911 Maximum Size Subarray Sum Equals k JavaScript Medium
912 Best Meeting Point Hard
913 Flip Game II Medium
914 Flip Game JavaScript Easy
915 Inorder Predecessor in BST Java Medium
916 Palindrome Permutation JavaScript Easy
917 Palindrome Permutation II Medium
918 3Sum Smaller JavaScript Medium
919 Meeting Rooms II Medium
920 Meeting Rooms JavaScript Easy
921 Count Univalue Subtrees TypeScript Medium
922 Group Shifted Strings Medium
923 Strobogrammatic Number III Hard
924 Shortest Word Distance JavaScript Easy
925 Shortest Word Distance II Medium
926 Shortest Word Distance III Medium
927 Reverse Words in a String II JavaScript Medium
928 Longest Substring with At Most Two Distinct Characters Medium
930 Connected Components in List Medium
931 Median of K Sorted Arrays Hard
932 Friends Within Three Jumps Medium
933 Tuple Multiply Medium
934 Unlock Problem Medium
935 Cartesian Product Medium
936 Capitalizes The First Letter JavaScript Easy
937 How Many Problem Can I Accept TypeScript Medium
939 Binary Tree Kth Floor Node Medium
940 Maximum Absolute Value Medium
941 Sliding Puzzle Hard
943 Range Sum Query - Immutable Python Easy
944 Maximum Submatrix Medium
945 Task Scheduler Medium
946 233 Matrix Super
947 Matrix Power Series Hard
948 Sequence Count Super
949 Fibonacci II Medium
950 Sliding Puzzle III Hard
951 Rearrange Easy
952 Digital Problem Easy
953 The Biggest Score On The Tree Medium
954 Insert Delete GetRandom O(1) - Duplicates allowed Hard
955 Implement Queue by Circular Array Python Medium
956 Data Segmentation Easy
957 Radar Detection Easy
958 Palindrome Data Stream Easy
959 K Spaced Array Sorting Medium
960 First Unique Number in Data Stream II Python Medium
961 Design Log Storage System Medium
962 Condition string Medium
963 The Judges Give Problem Medium
964 Food Set TypeScript Medium
965 LR String Medium
966 Closest Pair of Points Hard
967 Quality Inspection Hard
968 Valid Currency Amount Medium
969 Longest Repeating Substring II Medium
970 Big Business Easy
971 Surplus Value Backpack Hard
972 Deliver The Message Medium
973 1-bit and 2-bit Characters JavaScript Easy
974 01 Matrix JavaScript Medium
975 2 Keys Keyboard Medium
976 4Sum II JavaScript Medium
977 Base 7 JavaScript Easy
978 Basic Calculator Medium
979 Additive Number TypeScript Medium
980 Basic Calculator II Medium
981 Basic Calculator IV Hard
982 Arithmetic Slices JavaScript Medium
983 Baseball Game JavaScript Easy
984 Arithmetic Slices II - Subsequence Hard
985 Can I Win Hard
986 Battleships in a Board Python Medium
987 Binary Number with Alternating Bits JavaScript Easy
988 Arranging Coins JavaScript Easy
989 Array Nesting TypeScript Medium
990 Beautiful Arrangement Medium
991 Bulb Switcher Medium
992 Beautiful Arrangement II Medium
993 Array Partition I JavaScript Easy
994 Contiguous Array JavaScript Medium
995 Best Time to Buy and Sell Stock with Cooldown JavaScript Medium
996 Maximum Slope Straight Line Medium
997 Print Organization Chart Medium
998 Construction Queue Hard
999 implement-deque-by-circular-array Medium
1000 Best Time to Buy and Sell Stock with Transaction Fee JavaScript Medium
1001 Asteroid Collision JavaScript Medium
1002 Bus Routes Medium
1003 Binary Tree Pruning JavaScript Easy
1004 Largest Sum of Averages JavaScript Medium
1005 Largest Triangle Area JavaScript Easy
1006 Subdomain Visit Count JavaScript Easy
1007 Chalkboard XOR Game Medium
1008 Expressive Words Medium
1009 Soup Servings Medium
1010 Max Increase to Keep City Skyline JavaScript Medium
1011 Number of Lines To Write String JavaScript Easy
1012 Split Array With Same Average Hard
1013 Unique Morse Code Words JavaScript Easy
1014 Bricks Falling When Hit Hard
1015 Find Eventual Safe States Medium
1016 Minimum Swaps To Make Sequences Increasing Medium
1017 Similar RGB Color JavaScript Easy
1018 Champagne Tower JavaScript Medium
1019 Smallest Rotation with Highest Score Hard
1020 All Paths From Source to Target TypeScript Medium
1021 Number of Subarrays with Bounded Maximum Medium
1022 Valid Tic-Tac-Toe State JavaScript Medium
1023 Preimage Size of Factorial Zeroes Function TypeScript Hard
1024 Number of Matching Subsequences Medium
1025 Custom Sort String Medium
1026 Domino and Tromino Tiling Medium
1027 Escape The Ghosts JavaScript Medium
1028 Rotated Digits TypeScript Easy
1029 Cheapest Flights Within K Stops Medium
1030 K-th Smallest Prime Fraction Hard
1031 Is Graph Bipartite? TypeScript Medium
1032 Letter Case Permutation JavaScript Easy
1033 Minimum Difference Between BST Nodes JavaScript Easy
1034 Transform to Chessboard Hard
1035 Rabbits in Forest JavaScript Medium
1036 Reach Points Hard
1037 Global and Local Inversions Medium
1038 Jewels And Stones JavaScript Easy
1039 Max Chunks To Make Sorted TypeScript Medium
1040 Max Chunks To Make Sorted II Hard
1041 Reorganize String JavaScript Medium
1042 Toeplitz Matrix JavaScript Easy
1043 Couples Holding Hands Hard
1044 Largest Plus Sign TypeScript Medium
1045 Partition Labels Medium
1046 Prime Number of Set Bits in Binary Representation TypeScript Easy
1047 Special Binary String Medium
1048 Set Intersection Size At Least Two Hard
1049 Pyramid Transition Matrix Medium
1050 Cracking the Safe Hard
1051 Contain Virus Hard
1052 Shortest Completing Word Medium
1053 Largest Number At Least Twice of Others JavaScript Easy
1054 Min Cost Climbing Stairs JavaScript Easy
1056 Find Smallest Letter Greater Than Target JavaScript Easy
1057 Network Delay Time Medium
1058 Cherry Pickup Hard
1059 Delete and Earn JavaScript Medium
1060 Daily Temperatures Python Medium
1061 Parse Lisp Expression Hard
1062 Flood Fill JavaScript Easy
1063 My Calendar III Hard
1064 My Calendar II Medium
1065 My Calendar I Medium
1066 Verify Preorder Serialization of a Binary Tree JavaScript Medium
1067 Split Array in Parts Medium
1068 Find Pivot Index JavaScript Easy
1069 Remove Comments Medium
1070 Accounts Merge Medium
1071 Longest Word in Dictionary TypeScript Easy
1072 Find K-th Smallest Pair Distance Hard
1073 Maximum Length of Repeated Subarray Medium
1074 Range Module Hard
1075 Subarray Product Less Than K Medium
1076 Minimum ASCII Delete Sum for Two Strings JavaScript Medium
1077 Falling Squares Hard
1078 Degree of an Array TypeScript Easy
1079 Count Binary Substrings TypeScript Easy
1080 Max Area of Island JavaScript Easy
1081 Stickers to Spell Word Hard
1082 Employee Importance Python Easy
1083 Maximum Sum of 3 Non-Overlapping Subarrays Hard
1084 Knight Probability in Chessboard Medium
1085 Longest Univalue Path JavaScript Easy
1086 Repeated String Match TypeScript Easy
1087 Redundant Connection II Hard
1088 Redundant Connection Medium
1089 Valid Parenthesis String JavaScript Medium
1090 Map Sum Pairs Medium
1092 Cut Off Trees for Golf Event Hard
1093 Number of Longest Increasing Subsequence JavaScript Medium
1094 Second Minimum Node In a Binary Tree JavaScript Easy
1095 Maximum Swap JavaScript Medium
1096 Greatest Least Common Multiple Medium
1097 Kth Smallest Number in Multiplication Table Hard
1098 Path Sum IV TypeScript Medium
1099 Non-decreasing Array JavaScript Easy
1100 Strange Printer Hard
1101 Maximum Width of Binary Tree JavaScript Medium
1102 Image Smoother TypeScript Easy
1103 Split Array into Consecutive Subsequences Medium
1104 Judge Route Circle TypeScript Easy
1105 Print Binary Tree JavaScript Medium
1106 Maximum Binary Tree JavaScript Easy
1109 Dota2 Senate Medium
1110 Replace Words TypeScript Medium
1111 Maximum Length of Pair Chain Medium
1112 Set Mismatch JavaScript Easy
1113 Solve the Equation Medium
1114 Shopping Offers Medium
1115 Average of Levels in Binary Tree JavaScript Easy
1116 Exclusive Time of Functions Medium
1117 Smallest Range Hard
1118 K Inverse Pairs Array Hard
1122 Add One Row to Tree JavaScript Medium
1125 Jump Pillar Medium
1126 Merge Two Binary Trees JavaScript Easy
1127 Add Bold Tag in String Medium
1129 Smallest Subtree with All the Deepest Nodes TypeScript Medium
1130 Magic circle Hard
1131 The Function in Permutations Medium
1132 Valid Triangle Number TypeScript Medium
1133 Group Buy TypeScript Easy
1134 Find Duplicate File in System JavaScript Medium
1135 Feature extraction Easy
1136 High Click Induction Area TypeScript Medium
1137 Construct String from Binary Tree JavaScript Easy
1138 Can Place Flowers JavaScript Easy
1139 the kth subarray Hard
1141 The month's days TypeScript Easy
1142 Non-negative Integers without Consecutive Ones Hard
1143 Minimum Index Sum of Two Lists JavaScript Easy
1144 Range Addition II TypeScript Easy
1145 Associated query Easy
1146 Chess piece rotation Easy
1147 Work Plan Medium
1148 Longest Harmonious Subsequence TypeScript Easy
1149 Valid Square JavaScript Medium
1150 Fraction Addition and Subtraction Medium
1151 Tag Validator Hard
1152 Erect the Fence Hard
1153 string sorting TypeScript Easy
1154 Attendance Judgment TypeScript Easy
1156 Delete Operation for Two Strings JavaScript Medium
1157 Shortest Unsorted Continuous Subarray TypeScript Easy
1158 Plant flowers Medium
1159 Longest Common Prefix III Hard
1160 Campus Bikes Medium
1161 goods transfer Hard
1162 Out of Boundary Paths Medium
1163 Distribute Candies JavaScript Easy
1164 Wiggle Subsequence Medium
1165 Subtree of Another Tree JavaScript Easy
1166 Recommended Results are Scattered TypeScript Easy
1167 Top three numbers Medium
1168 array score TypeScript Easy
1169 Permutation in String JavaScript Medium
1170 Reshape the Matrix JavaScript Easy
1171 Find the Closest Palindrome Hard
1172 Binary Tree Tilt JavaScript Easy
1173 Reverse Words in a String III JavaScript Easy
1174 Next Greater Element III Medium
1175 Brick Wall Medium
1176 Optimal Division Medium
1177 Student Attendance Record II Hard
1178 Student Attendance Record I JavaScript Easy
1179 Friend Circles Medium
1180 Remove Boxes Hard
1181 Diameter of Binary Tree JavaScript Easy
1182 Reverse String II JavaScript Easy
1183 Single Element in a Sorted Array JavaScript Medium
1184 Minimum Time Difference JavaScript Medium
1185 Complex Number Multiplication JavaScript Medium
1186 Encode and Decode TinyURL Python Medium
1187 K-diff Pairs in an Array JavaScript Easy
1188 Minimum Absolute Difference in BST JavaScript Easy
1189 Minesweeper Python Medium
1190 Longest Word in Dictionary through Deleting Medium
1191 Longest Uncommon Subsequence II Medium
1192 Longest Uncommon Subsequence I TypeScript Easy
1193 Detect Capital JavaScript Easy
1194 Super Washing Machines Hard
1195 Find Largest Value in Each Tree Row JavaScript Medium
1196 Freedom Trail Hard
1197 Find Bottom Left Tree Value JavaScript Medium
1198 Most Frequent Subtree Sum TypeScript Medium
1199 Perfect Number TypeScript Easy
1200 Relative Ranks JavaScript Easy
1201 Next Greater Element II Medium
1202 IPO TypeScript Hard
1203 Find Mode in Binary Search Tree JavaScript Medium
1204 Keyboard Row JavaScript Easy
1205 Diagonal Traverse JavaScript Medium
1206 Next Greater Element I TypeScript Easy
1207 Teemo Attacking Medium
1208 Target Sum JavaScript Medium
1209 Construct the Rectangle JavaScript Easy
1210 Increasing Subsequences Medium
1211 Zuma Game Hard
1212 Max Consecutive Ones JavaScript Easy
1213 Smallest Good Base Hard
1214 License Key Formatting JavaScript Easy
1215 Magical String TypeScript Medium
1216 Largest Palindrome Product TypeScript Easy
1217 Total Hamming Distance TypeScript Medium
1218 Number Complement JavaScript Easy
1219 Heaters TypeScript Medium
1220 Matchsticks to Square TypeScript Medium
1221 Concatenated Words Hard
1222 Validate IP Address TypeScript Medium
1223 Unique Substrings in Wraparound String Medium
1224 Count The Repetitions Hard
1225 Island Perimeter TypeScript Easy
1226 Minimum Moves to Equal Array Elements II TypeScript Medium
1227 Repeated Substring Pattern JavaScript Easy
1228 Poor Pigs Easy
1229 Circular Array Loop Medium
1230 Assign Cookies JavaScript Easy
1231 Minimum Moves to Equal Array Elements Easy
1232 Minimum Number of Arrows to Burst Balloons Medium
1233 Sort Characters By Frequency TypeScript Medium
1234 Delete Node in a BST Medium
1235 Serialize and Deserialize BST Python Medium
1236 Find All Numbers Disappeared in an Array JavaScript Easy
1237 Number of Boomerangs JavaScript Easy
1238 Find All Duplicates in an Array Python Medium
1239 K-th Smallest in Lexicographical Order Hard
1240 Path Sum III Easy
1241 Find Right Interval Medium
1242 Non-overlapping Intervals Medium
1243 Number of Segments in a String JavaScript Easy
1244 Minimum Genetic Mutation Medium
1245 All O(1) Data Structure Hard
1246 Longest Repeating Character Replacement Medium
1247 Reconstruct Original Digits from English TypeScript Medium
1248 Maximum XOR of Two Numbers in an Array Medium
1249 Strong Password Checker Hard
1250 Third Maximum Number JavaScript Easy
1251 Split Array Largest Sum JavaScript Hard
1252 Queue Reconstruction by Height Medium
1253 Convert a Number to Hexadecimal JavaScript Easy
1254 Sum of Left Leaves JavaScript Easy
1255 Remove K Digits Medium
1256 Nth Digit Easy
1257 Evaluate Division Medium
1258 Beautiful Subarrays Medium
1259 Integer Replacement TypeScript Medium
1260 Rotate Function Medium
1261 Longest Substring with At Least K Repeating Characters Medium
1262 UTF-8 Validation TypeScript Medium
1263 Is Subsequence JavaScript Medium
1264 Perfect Rectangle Hard
1265 Elimination Game Medium
1266 Find the Difference JavaScript Easy
1267 Lexicographical Numbers JavaScript Medium
1269 Handkerchief Throwing Medium
1270 Ransom Note JavaScript Easy
1271 Critical Connections in a Network Hard
1272 Kth Smallest Element in a Sorted Matrix JavaScript Medium
1273 Maximum Length of Increasing String Hard
1274 Find K Pairs with Smallest Sums Medium
1275 Super Pow JavaScript Medium
1276 Sum of Two Integers Easy
1277 Water and Jug Problem Medium
1278 Max Sum of Rectangle No Larger Than K Hard
1279 Count Numbers with Unique Digits Medium
1280 Data Stream as Disjoint Intervals Hard
1281 Top K Frequent Elements Python Medium
1282 Reverse Vowels of a String JavaScript Easy
1283 Reverse String JavaScript Easy
1284 Integer Break JavaScript Medium
1285 Power of Four JavaScript Easy
1286 Self Crossing Hard
1287 Increasing Triplet Subsequence JavaScript Medium
1288 Reconstruct Itinerary Medium
1289 Number of Atoms Hard
1290 Patching Array Hard
1291 Sports Meeting Medium
1292 Odd Even Linked List JavaScript Medium
1293 Count of Range Sum Hard
1294 Power of Three JavaScript Easy
1295 Prime Factor Statistics Easy
1296 Maximum Product of Word Lengths TypeScript Medium
1297 Count of Smaller Numbers After Self TypeScript Hard
1298 Minimum Height Trees Medium
1299 Bulls and Cows TypeScript Medium
1300 Bash Game JavaScript Easy
1301 Game of Life Medium
1302 People Counting Easy
1303 H-Index II JavaScript Medium
1304 H-Index Medium
1306 Travel Plan II Hard
1307 Verify Preorder Sequence in Binary Search Tree JavaScript Medium
1308 Factor Combinations Medium
1309 Different Ways to Add Parentheses Medium
1310 Product of Array Except Self JavaScript Medium
1311 Lowest Common Ancestor of a Binary Search Tree Python Easy
1312 Number of Digit One JavaScript Hard
1313 Bipartite Graph Medium
1314 Power of Two JavaScript Easy
1315 Summary Ranges Medium
1316 Luck Number Hard
1317 Count Complete Tree Nodes JavaScript Medium
1318 Contains Duplicate III Medium
1319 Contains Duplicate II JavaScript Easy
1320 Contains Duplicate JavaScript Easy
1321 Combination Sum III Medium
1322 Product Equal B Hard
1323 Fetch supplies Medium
1324 Count Primes JavaScript Easy
1325 Bitwise AND of Numbers Range TypeScript Medium
1326 Boarder Sort TypeScript Medium
1327 delete string Easy
1328 Double Change Easy
1329 Sequence maintenance Hard
1330 zero matrix Hard
1331 English Software TypeScript Easy
1332 Number of 1 Bits JavaScript Easy
1333 Reverse Bits JavaScript Python Easy
1334 Rotate Array JavaScript Easy
1335 Repeated DNA Sequences JavaScript Medium
1336 Party Invitation Medium
1337 Maximum possible value Medium
1338 Parking Dilemma TypeScript Easy
1339 Maximum Range Hard
1340 add character Easy
1341 Combine New Numbers Medium
1342 substitute string Medium
1343 Sum of Two Strings Python Easy
1344 Counter Diagonal Sort TypeScript Medium
1345 Robot Encircular Medium
1346 Dungeon Game Hard
1347 Factorial Trailing Zeroes JavaScript Easy
1348 Excel Sheet Column Number JavaScript Easy
1350 Excel Sheet Column Title JavaScript Easy
1351 Fraction to Recurring Decimal Medium
1352 Compare Version Numbers JavaScript Medium
1353 Sum Root to Leaf Numbers JavaScript Medium
1354 Pascal's Triangle II JavaScript Easy
1355 Pascal's Triangle JavaScript Easy
1356 Maximum Points Set Medium
1357 Path Sum II JavaScript Medium
1358 Path Sum JavaScript Easy
1359 Convert Sorted Array to Binary Search Tree JavaScript Easy
1360 Symmetric Tree JavaScript Medium
1361 Text Justification Hard
1362 Substring with Concatenation of All Words Hard
1363 ZigZag Conversion TypeScript Medium
1364 the minium distance Medium
1365 Minimum Cycle Section Hard
1366 Directed Graph Loop Medium
1367 Police Distance Medium
1368 Same Number JavaScript Easy
1369 Most Common Word TypeScript Easy
1370 Race Car Hard
1371 Linked List Components JavaScript Medium
1372 Ambiguous Coordinates TypeScript Medium
1373 Movies on Flight Medium
1374 Shortest Distance in 3D Space Medium
1375 Substring With At Least K Distinct Characters Medium
1376 Equivalent Strings Medium
1377 Find Substring Medium
1378 Minimum String Array Coverage Medium
1379 The Longest Scene Hard
1380 Log Sorting Easy
1381 Maximum Line Coverage Hard
1382 High Capacity Backpack Hard
1383 Subtree Count Hard
1384 Segment Stones Merge Super
1385 Lucky Number Eight Easy
1386 Cable Car Ride Easy
1387 Binary Trees With Factors Medium
1388 Card Flipping Game Medium
1389 Shortest Distance to a Character Easy
1390 Short Encoding of Words Medium
1391 Making A Large Island Hard
1392 Most Profit Assigning Work Medium
1393 Friends Of Appropriate Ages TypeScript Medium
1394 Goat Latin JavaScript Easy
1395 The Barycentre Of The Trees Hard
1396 Set Union Medium
1397 Digital Coverage Medium
1398 K Decimal Addition Easy
1399 Take Coins Medium
1400 Fermat Point Of Graphs Hard
1401 Twitch Words JavaScript Easy
1402 Recommend Friends Medium
1403 Maximum Product Path Medium
1408 Gas Station II Hard
1409 Matrix Finding Number Medium
1410 Matrix Water Injection Medium
1411 Edit Distance - Replace Edition Medium
1412 Pick Three Numbers Medium
1413 Tree Medium
1414 Eat The Beans Hard
1415 Residual Product Easy
1416 The Previous Number Medium
1417 Weighing Problem Easy
1418 Path With Maximum Minimum Value Medium
1420 Minimum Window Substring II Medium
1421 Matrix Game Easy
1422 Shortest Path Visiting All Nodes Hard
1423 Hand of Straights Medium
1424 Longest Mountain in Array JavaScript Medium
1425 Backspace String Compare JavaScript Easy
1426 Robot jumping Hard
1427 Split Array into Fibonacci Sequence Medium
1428 Keys and Rooms Medium
1430 Similar String Groups Hard
1431 Push Dominoes Medium
1432 New 21 Game Medium
1433 Image Overlap Medium
1434 Sum of Distances in Tree Hard
1435 Find And Replace in String Medium
1436 Flipping an Image Easy
1437 Masking Personal Information TypeScript Medium
1438 Positions of Large Groups JavaScript Easy
1439 Consecutive Numbers Sum TypeScript Medium
1440 Unique Letter String Hard
1441 Four Numbers Multiply Problem Hard
1442 Order Problem Medium
1443 Longest AB Substring Easy
1444 Dyeing Problem Medium
1446 01 Matrix Walking Problem Medium
1447 Calculation The Sum Of Path Medium
1448 Card Game Medium
1449 Loud and Rich Medium
1450 Rectangle Area II Hard
1451 Maximize Distance to Closest Person JavaScript Easy
1452 Shifting Letters Medium
1453 Minimum Amount Medium
1454 Word Frequency Count Medium
1455 Valid Array Easy
1456 Word Synthesis Problem Hard
1457 Search Subarray TypeScript Medium
1458 Minimum Submatrix Medium
1459 Judge the last number Easy
1463 Paper Review Medium
1464 The K-th Combination Hard
1465 Order Of Tasks Medium
1466 Best Shopping Plan Medium
1467 Ask For Cooling Time Medium
1468 Two Numbers That Are Not Repeated Hard
1469 Longest Path On The Tree Medium
1470 The Game Of Take Numbers Medium
1471 Set Operation Easy
1472 Twins Strings Easy
1473 Find The Sum Of The Array Medium
1474 Shortest Phrase Medium
1475 Minimum Legal Bracket Sequence Hard
1476 Peak Index in a Mountain Array TypeScript Easy
1477 Car Fleet JavaScript Medium
1478 Closest Target Value Easy
1479 Can Reach The Endpoint Easy
1480 Dot Product Easy
1481 Unique Substring Medium
1482 Minimum Sum Path Medium
1483 Maximum Average Score JavaScript Easy
1484 The Most Frequent word Medium
1486 Function Runtime Easy
1487 Judging Triangle Medium
1489 The Largest Sum Of The Matrix Boundary Elements Medium
1490 K-Similar Strings Hard
1491 Score of Parentheses Medium
1492 Koko Eating Bananas JavaScript Medium
1493 Walking Robot Simulation Easy
1494 Length of Longest Fibonacci Subsequence Medium
1495 Leaf-Similar Trees JavaScript Easy
1496 Implement Rand10() Using Rand7() Python Medium
1497 Minimum Number of Refueling Stops Hard
1498 Advantage Shuffle Medium
1499 Reordered Power of 2 JavaScript Medium
1500 Binary Gap Easy
1501 Transpose Matrix Easy
1502 Prime Palindrome Medium
1503 Give change Easy
1504 Shortest Path to Get All Keys Hard
1505 Find the Number Python Easy
1506 All Nodes Distance K in Binary Tree Python Medium
1507 Shortest Subarray with Sum at Least K Hard
1508 Score After Flipping Matrix JavaScript Medium
1509 Lemonade Change JavaScript Easy
1510 Buddy Strings JavaScript Easy
1511 Mirror Reflection Medium
1512 Minimum Cost to Hire K Workers Hard
1513 Exam Room Medium
1514 Robot Room Cleaner Hard
1516 Xor Sum Super
1517 Largest subarray JavaScript Easy
1518 Watering Flowers Medium
1521 Unique Twitter User Id Set Easy
1522 Search in a Sorted Array of Unknown Size Medium
1523 Partitioning Array TypeScript Easy
1524 Search in a Binary Search Tree JavaScript Easy
1525 N-ary Tree Postorder Traversal Python Easy
1526 N-ary Tree Preorder Traversal Python Easy
1527 Majsoul on ! Medium
1528 number schemes Hard
1529 Triplet Subarray With Absolute Diff Less Than or Equal to Limit Medium
1530 Encode N-ary Tree to Binary Tree Hard
1531 Automatic Proofreading Program Medium
1532 Serialize and Deserialize N-ary Tree Hard
1533 N-ary Tree Level Order Traversal TypeScript Easy
1534 Convert Binary Search Tree to Sorted Doubly Linked List Medium
1535 To Lower Case JavaScript Easy
1536 Find First and Last Position of Element in Sorted Array JavaScript Medium
1537 Swap Zero-One Medium
1538 Card Game II Medium
1539 Flipped the Pixel Medium
1540 Can Convert TypeScript Easy
1541 Put Box Medium
1542 NextTime Norepeat Medium
1543 Unique Path IV Medium
1544 Magic Square Hard
1545 Last Closest Time Medium
1546 Coin Problem Easy
1552 Parking Problem Medium
1553 Climbing Stairs III Medium
1554 LastTime Norepeat Medium
1555 Flower Problem Hard
1556 Guess Game Hard
1557 Array Maximum Value Hard
1558 Interlaced Positive And Negative Numbers Hard
1559 Take the element and query the sum Easy
1560 MinimumString Medium
1561 BST Node Distance Medium
1562 Number of restaurants Medium
1563 Shortest path to the destination Medium
1564 Interval Search Easy
1565 Modern Ludo I Medium
1566 Minimum Difference Hard
1567 Maximum Can Exchanged Subarray Medium
1568 Poison Test Medium
1569 Social Network Medium
1570 Binary Stream Easy
1571 Top K GPA Medium
1572 Asking For The Longest 01 Substring Medium
1573 Legal String Medium
1574 Music Playlist Hard
1575 Spring Tour Easy
1576 Optimal Match Hard
1577 Sum of leaf nodes Medium
1578 Number of A JavaScript Medium
1579 Alphabetic string calculation Medium
1580 Transition String Medium
1581 Longest Subsequence JavaScript Medium
1582 Minimum Path Sum II Medium
1583 Maximum Number Sum Medium
1584 Number Of Xor Values Medium
1585 Moving Stones Easy
1586 Minimum Number Of Keystrokes Medium
1587 String Segmentation TypeScript Medium
1588 All Possible Full Binary Trees Medium
1589 Groups of Special-Equivalent Strings Easy
1590 Surface Area of 3D Shapes Easy
1591 Sum of Subsequence Widths Hard
1592 Find and Replace Pattern Medium
1593 Construct Binary Tree from Preorder and Postorder Traversal JavaScript Medium
1594 Fair Candy Swap JavaScript Easy
1596 Possible Bipartition Medium
1597 Spiral Matrix III Medium
1598 Uncommon Words from Two Sentences JavaScript Easy
1599 Projection Area of 3D Shapes Easy
1600 Reachable Nodes In Subdivided Graph Hard
1601 Boats to Save People JavaScript Medium
1602 Decoded String at Index TypeScript Medium
1604 Maximum Sum of Two Numbers TypeScript Medium
1607 Profitable Schemes Hard
1608 Nth Magical Number Hard
1609 Middle of the Linked List JavaScript Easy
1610 Find the numbers Medium
1611 Shortest subarray Medium
1612 Smallest Path Medium
1613 Highest frequency IP TypeScript Naive
1614 Highest growth stock Easy
1615 The result of investment Easy
1616 Shortest subarray II Hard
1617 Array Maximum Difference Easy
1618 Processing Form Medium
1619 Candy II Medium
1620 Collecting Coins Super
1621 Cut Connection Easy
1623 Minimal Distance In The Array Easy
1624 Max Distance Hard
1625 Words Compression Hard
1626 Salary Adjustment Medium
1627 Word Segmentation Medium
1628 Driving problem Medium
1629 Find the nearest store Medium
1630 Interesting String Medium
1631 Interesting Subarray Medium
1632 Count email groups Easy
1633 Strings That Satisfies The Condition Easy
1634 Secret Word Medium
1635 Max Pair Medium
1636 Aerial Movie Medium
1637 Tree problem Medium
1638 Least Substring Easy
1639 K-Substring with K different characters Medium
1640 Duplicates Digits Hard
1641 Max Remove Order Medium
1642 Query String Medium
1643 Pick Fruits Medium
1644 Plane Maximum Rectangle Medium
1645 Least Subsequences Medium
1646 CheckWords Medium
1647 Path Search Medium
1648 max substring Hard
1649 Super Lollipop TypeScript Easy
1656 Legal Number Statistics JavaScript Easy
1657 Operation Time Easy
1659 Legal Number Statistics II TypeScript Easy
1665 Calculate number JavaScript Easy
1669 Build a temple TypeScript Medium
1685 The mazeIV Medium
1691 Best Time to Buy and Sell Stock V Medium
1694 Monster Hunter Hard
1698 Delete Columns to Make Sorted Easy
1699 Find the Shortest Superstring Hard
1700 DI String Match Easy
1701 Valid Mountain Array Easy
1702 Distinct Subsequences II JavaScript Hard
1703 Minimum Area Rectangle Medium
1704 Range Sum of BST JavaScript Medium
1705 Compare Strings II Easy
1706 Stamping The Sequence Hard
1707 Knight Dialer Medium
1708 Shortest Bridge Medium
1709 Number of Recent Calls Easy
1710 Beautiful Array Medium
1711 Minimum Falling Path Sum JavaScript Medium
1712 Binary Subarrays With Sum TypeScript Medium
1713 Unique Email Addresses Easy
1714 Minimize Malware Spread II Hard
1715 Three Equal Parts TypeScript Medium
1716 Flip String to Monotone Increasing JavaScript Medium
1718 Minimize Malware Spread Hard
1719 3Sum With Multiplicity JavaScript Medium
1721 Minimum Add to Make Parentheses Valid JavaScript Medium
1722 Number of Music Playlists Hard
1723 Shortest Path in a Grid with Obstacles Elimination Medium
1724 Maximum Sum Circular Subarray JavaScript Medium
1725 Reverse Only Letters Easy
1726 Word Subsets Medium
1727 Partition Array into Disjoint Intervals JavaScript Medium
1728 X of a Kind in a Deck of Cards Python Easy
1729 Cat and Mouse Hard
1730 Spreadsheet Notation Conversion Easy
1731 Smallest Range II Medium
1732 Snakes and Ladders Medium
1733 Smallest Range I Easy
1734 Sum of Subarray Minimums Medium
1735 Super Palindromes Hard
1736 Throw garbage Medium
1737 Fruit Into Baskets Medium
1738 Valid Permutations for DI Sequence Hard
1739 Numbers At Most N Given Digit Set Medium
1740 Online Stock Span Medium
1741 RLE Iterator Medium
1742 Orderly Queue Hard
1743 Bitwise ORs of Subarrays Medium
1744 Increasing Order Search Tree JavaScript Easy
1745 Monotonic Array JavaScript Easy
1746 Minimum Distance Between BST Nodes JavaScript Easy
1747 Robot Return to Origin Easy
1753 Doing Homework TypeScript Medium
1756 Buy beverage Medium
1761 Digital Huarong Road Hard
1767 Minimum Tree Coverage Hard
1772 Number of collections Super
1778 Odd Even Jump Hard
1779 Shortest Duplicate Subarray JavaScript Easy
1780 The Candidate With the Most Votes Easy
1781 Reverse ASCII Encoded Strings Easy
1782 No Pairs Allowed Medium
1783 Binary Tree Postorder Traversal-null JavaScript Easy
1784 Decrease To Be Palindrome Easy
1786 Pub Sub Pattern Easy
1787 Google Suggestion (Map Reduce) Medium
1788 Ascending Binary Sorting Medium
1789 Distinguish Username Easy
1790 Rotate String II TypeScript Easy
1791 Simple queries Medium
1792 Cut the sticks Easy
1793 Balanced Array Easy
1794 Count Duplicates Easy
1795 Is Possible Medium
1796 K-Difference Medium
1797 optimalUtilization Easy
1798 Minimum Cost to Merge Stones Hard
1799 Sequence summation Easy
1800 Float Combination Sum Medium
1801 the sum of legal set Easy
1802 Grid Game Medium
1803 Rotate beam Hard
1804 Find The Rank Easy
1807 Fibonacci easy Python Easy
1808 Minimum Domino Rotations For Equal Row Medium
1811 Find Maximum Gold Medium
1812 Rotation Number Easy
1813 Construct Binary Tree Medium
1814 Sum of all Subarrays Python Easy
1815 Threhold Alerts Easy
1816 Find the Smallest Divisor Given a Threshold TypeScript Medium
1817 Divide Chocolate Hard
1819 Longest Semi Alternating Substring Easy
1820 Find Letter TypeScript Easy
1821 Min Deletions To Obtain String in Right Format TypeScript Easy
1822 Minimum Moves TypeScript Easy
1823 Longest Prefix of Array Easy
1824 Most Frequent Substring Medium
1825 Number Change Medium
1827 Number of Ways to Stay in the Same Place After Some Steps II TypeScript Medium
1828 Lake Escape Hard
1829 Find the number of shortest path Medium
1831 Array Summarization Easy
1832 Minimum Step Medium
1833 pen box Medium
1834 Grouping Options Hard
1835 Number of Ways to Stay in the Same Place After Some Steps I TypeScript Easy
1836 Reaching Point Medium
1840 Matrix restoration Medium
1844 subarray sum equals to k II Medium
1846 Reaching Point II Medium
1848 Word Search III Hard
1849 Grumpy Bookstore Owner TypeScript Medium
1850 Pick Apples TypeScript Medium
1851 Buy Passes TypeScript Medium
1852 Final Discounted Price TypeScript Medium
1853 Efficient Job Processing Service Medium
1854 Partition Array III Easy
1855 Reach Destination Hard
1856 Sub-palindrome Easy
1857 Find Friend Circle Number Medium
1858 Set of boxes Hard
1859 Minimum Amplitude Easy
1860 the Number of 0-submatrix Hard
1861 Rat Jump Hard
1862 Time to Flower Tree Medium
1867 Most Frequent Word II Easy
1868 Find the Number of “Balance” in the String Medium
1869 Count Square Submatrices with All Ones Medium
1870 Number of Substrings with All Zeroes TypeScript Medium
1871 Maximum moment TypeScript Easy
1872 Minimum Cost to Connect Sticks TypeScript Medium
1874 Kth Smallest Element in a Specific Array Medium
1876 Alien Dictionary(easy) TypeScript Easy
1877 longest super sequence Medium
1878 Rotated Nums TypeScript Easy
1879 Two Sum VII Hard
1880 Largest Number X Which Occurs X Times Easy
1881 Aircraft seat TypeScript Easy
1882 Fair Indexes TypeScript Medium
1883 Top K Frequently Mentioned Keywords Medium
1884 Take Away The Bottle Hard
1885 A Strange Sorting Problem Hard
1886 Moving Target TypeScript Easy
1887 Stretch Word TypeScript Easy
1888 Shortest Path in Matrix Medium
1889 Interval Merge Medium
1890 Form Minimum Number Medium
1891 Travel Plan Medium
1892 Mine-sweeping Medium
1893 the Valid String Medium
1894 Ad Click Analysis Easy
1895 Arrange interview city TypeScript Easy
1896 Pick Carrots TypeScript Easy
1897 Meeting Room III Medium
1899 Fetch supplies II Medium
1900 Gene Similarity Hard
1901 Squares of a Sorted Array TypeScript Easy
1902 Find Google TypeScript Easy
1903 Department Statistics Easy
1904 Place the Balls Hard
1905 Character deletion JavaScript Easy
1906 Look for points that are bigger than the surrounding area TypeScript Easy
1907 Array Game Medium
1908 Boolean expression evaluation Hard
1909 Order allocation Medium
1910 Most numbers TypeScript Naive
1911 As Far from Land as Possible TypeScript Medium
1913 Query Student Enrollment Information Naive
1914 Smart Sale JavaScript Medium
1915 Lifting Weights Hard
1916 Longest lighting time TypeScript Easy
1917 Cutting Metal Surplus Medium
1918 The height of the second tallest player Medium
1919 Members Whose Scores Exceed the Group leader Naive
1920 Find a Classmate with the Same Name Naive
1921 Players Who Never Recharge Naive
1922 Delete Duplicate Names Medium
1923 Increasing Number of Infections Naive
1924 Recommend Student to Study Science Naive
1925 At Least Three Players Have Scored Naive
1926 Popular Hero Naive
1927 Coin Flip Naive
1928 Analysis of Online Class I Naive
1929 Analysis of Online Class II Medium
1930 Public Rental Housing Information Query Naive
1931 Find Specific Patient Naive
1932 Students with the Most Failed Subjects I Naive
1933 Students with the Most Failed Subjects II Medium
1934 Zhang San's Story I Naive
1935 Zhang San's Story II Medium
1936 Zhang San's Story III Medium
1937 Consecutive Empty Boxes Medium
1938 Query User Email Naive
1939 Resume Delivery I Medium
1940 Resume Delivery II Medium
1941 Find Right Triangle Naive
1942 Two Nearest Saplings Medium
1943 Looking for Students of a Certain Height Medium
1944 Bike Sharing Naive
1945 Club Annual Competition Score Ranking I Naive
1946 Club Annual Competition Score Ranking II Medium
1947 Install Django Naive
1948 Show Hello, world! in the home page Naive
1949 Count the Number of Users Naive
1950 Query courses with more than 800 students Naive
1951 Query courses with given teacher Naive
1952 Query teachers over 20 years old Naive
1953 Query the name of the Chinese teacher Naive
1954 Query course information with the number of students within a specified range Naive
1955 Query teachers who do not meet the conditions Naive
1956 Query information about Eastern Heretic teachers Naive
1957 Inquire about courses starting before May 2020 Naive
1958 Query the courses that meet the conditions taught by the specified teacher Naive
1959 Query information about Chinese and British teachers Naive
1960 Query course information for a specific time Naive
1961 Query information about non-Japanese and non-American teachers Naive
1962 Query courses with teacher id other than 1 and 3 Naive
1963 Search for teachers aged 20~25 whose nationality is not Chinese or British Naive
1964 Query for course information about the number of students within the specified range Naive
1965 Search for information on teachers who are not within the age range of 20 to 30 years Naive
1966 Use NOT BETWEEN to search for teachers with Chinese nationality Naive
1967 Search for courses starting with the letters 'D' to 'O' Naive
1968 Query the course name with the first two letters between 'Db' and 'Dy' Naive
1969 Query the courses starting in 2020 Naive
1970 Search for courses with a creation date of June to August 2020 Naive
1971 Search for teachers whose email is empty Naive
1972 Inquire about Chinese and Japanese teachers who have e-mail addresses Naive
1973 Search for all courses starting with the letter 'D' Naive
1974 Query teacher information by email Naive
1975 Inquire about the teacher who is Tencent's mailbox and is of Chinese nationality Naive
1976 Sort course information by number of students Naive
1977 Sorted by age of Chinese teachers in descending order Naive
1978 Sort by age of Chinese teachers in ascending order Naive
1979 Check the three courses with the lowest number of students Naive
1980 Search for the oldest Chinese teacher Naive
1981 Check the nationality of all teachers Naive
1982 Check the age of teachers and sort them in ascending order Naive
1983 Query the average number of students in the curriculum Naive
1984 Count the number of different teacher_id Naive
1985 Number of teachers aged 20 to 28 who are Chinese and British nationals Naive
1986 Query the maximum number of students in all courses Naive
1987 Find the age of the oldest Chinese teacher Naive
1988 Check the number of students in the course with the lowest number of students Naive
1989 Check the age of the youngest teacher Naive
1990 The total number of students enroll in all courses Naive
1991 Count the total number of students for teacher #3 Naive
1992 Check average course enrollment Naive
1993 Delete the course called Dynamic Programming Naive
1994 Update all course information Naive
1995 Check the average age of teachers over 20 years old Naive
1996 Determining whether a teacher has a mailbox Naive
1997 Check the information of teachers who do not have email and are older than 20 years old Naive
1998 Statistics for courses in January to May 2020 Naive
1999 Query the number of students and the course information that meets the requirements of the course name Naive
2000 Search for course information of System Design Naive
2001 Query the course information of 'Web' or 'Big Data' Naive
2004 Delete all courses until 2020 Naive
2005 Query information about 18-year-old Chinese teachers Naive
2006 Query all courses Naive
2007 Check course name and class size Naive
2008 Query the course information of two courses Naive
2009 Query all teachers Naive
2010 Search all course names Naive
2011 Search for information on courses with more than 1000 participants Naive
2012 Find course information for the course named Artificial Intelligence Naive
2013 Check the name of the teacher Naive
2014 Query course name and course creation time Naive
2015 Inserting Python course information into the course table Naive
2016 Update the email address of the designated teacher Naive
2017 Inserting SQL course information into the course table Naive
2018 Insert 'Flash Sale' course information into the specified column of the course schedule Naive
2019 Delete all rows in the table Naive
2020 Update on the number of students choosing artificial intelligence Naive
2021 Insert teacher information into the specified column of the teachers table Naive
2022 Delayed all course creation dates by one year Naive
2023 Calculate the number of days from 01/13/2018 to the time of course creation Naive
2024 Query the course name and year of creation date of all course schedules Naive
2025 Check the course creation time in the course schedule Naive
2026 Insert the current time into the table (accurate to milliseconds) Naive
2027 Query course creation date by 'year month' Naive
2028 Postpone all course creation dates by one day Naive
2029 Calculate the number of days from 03/26/2019 to the course creation time Naive
2030 Query the hours of all course creation times Naive
2031 Advance all course creation dates by one month Naive
2032 Advance all course creation dates by one day Naive
2033 Query the course name and creation time in seconds for all course schedules Naive
2034 Check the average age of teachers at the end of the specified mailbox Naive
2035 Calculate the number of years difference between the start date and the current date of all courses in the course schedule Naive
2036 Calculate the number of months difference between the given date and the creation date of all courses in the course schedule Naive
2037 Search for course titles and course dates through August 2020 Naive
2038 Search for the date and time in the course creation time of the course schedule respectively Naive
2039 Query the creation date of the course in the course schedule Naive
2040 Search for courses with an instructor id of less than 3 and more than 800 students Naive
2041 Search for information on courses taught by designated teachers Naive
2042 Query all course names in the course schedule and the year and month of the creation date Naive
2043 Search for courses created in the first quarter Naive
2044 Output Hello SQL Naive
2045 Output Hello LintCode Naive
2046 The date the course was created is displayed in 'year-month-day hour:minute:second' Naive
2047 Copy all the data in the teacher table to another table Medium
2048 Search for information on all courses taught by a given teacher Medium
2049 Change the course name created by the teacher Western Venom Medium
2050 Search for teacher‘s name and the name of courses they taught Easy
2051 Search for the names of teachers from China and the names of courses they taught Naive
2052 Check the name of the instructor, email address and the name of courses they taught Naive
2053 Check the name, email and course name of the teacher from China Naive
2054 Check the course name and the age of the corresponding instructor Naive
2055 Search for all course names and their corresponding instructor names and nationalities Naive
2056 Copy the data in the teachers table that are older than 20 to another table Medium
2057 Modify course information created by instructor Eastern Heretic Naive
2058 Delete all courses for teachers younger than 21 years old Medium
2059 Remove faculty who have created courses before 2020 Medium
2060 Search for the name of the teacher for the 'Big Data' course Easy
2061 Check the course title and email address of the instructor Naive
2062 Query the id and name of all courses taught by the specified teacher Easy
2063 Search for the names of all courses taught by teachers whose nationality is 'USA' Medium
2064 Check course information for courses with more students than Western Venom teachers Medium
2065 Check the course names of all courses taught by all teachers who are older than 20 years old Medium
2066 Search for course information for courses with more students than the number of students in all courses of the oldest teacher Medium
2067 Search for information on any course with more students than the 'Eastern Heretic' class size Medium
2068 Check the maximum age of teachers of different nationalities Medium
2069 Search for the course name and number of students in the course with the highest number of students per instructor Medium
2070 Search for the name of a course created later than the creation time of any of the specified teacher's courses Medium
2071 Search for information on the oldest faculty member whose nationality is American Medium
2072 Search for course names of all courses taught by teachers who are not older than 20 years old Medium
2073 Query the id and and the number of students for all courses taught by teachers whose nationality is not 'USA' and 'UK' Easy
2074 Search for the names of teachers whose average number of students in classes taught by all teachers exceeds the average number of students in all courses Medium
2075 Check the number of teachers in different countries Naive
2076 Search for teacher information based on national average age Medium
2077 Search for information on courses and instructors with the highest number of students Medium
2078 Find out the number of teachers of different ages Naive
2079 Count the total number of students in each teacher's course Medium
2080 Search for the name of the instructor and the total number of students in all the instructor's courses with less than 3000 students Naive
2081 Insert the current date into the table Naive
2082 Statistics on the number of courses taught by each teacher Easy
2083 Create student table and add primary key constraint on ID column Naive
2084 Add primary key constraints to the course table courses Naive
2085 Remove the primary key constraint from the course table courses Naive
2086 Query the Nationality of Teachers Starting with ‘U’ and the Total Number of Students Between 2000 and 5000 and the Total Number of Students of Teachers of That Nationality Easy
2087 Implemente Linear Regression based on sklearn Easy
2088 First Java Code: Print Hello World Java Naive
2089 Implement timer decorator Medium
2090 Print Zero, Even and Odd Number II Medium
2091 Adding Foreign Key Constraints to Course Tables Easy
2092 Search for a lecturer number Easy
2093 Check the portfolio of courses and teachers Naive
2097 Find the sum of two parameters Naive
2098 Read the values in the file and sum them Naive
2105 Write Hello World! in the file Naive
2106 Create a file directory and write Hello World! Naive
2107 Copy files in bulk Medium
2123 Get yesterday's date Naive
2124 print hello Naive
2125 Call the methods in the file main Naive
2126 Import one of the files in a module folder Naive
2127 Implementing reverse sorting of numbers in a list Naive
2128 Use of list built-in methods Naive
2129 Modify the value of a specified subscript of a list Naive
2130 The subscript element of the specified list Naive
2131 Nesting of lists Naive
2132 Importing a module Naive
2133 Use list derivatives to filter elements in any range Naive
2134 General operation of the list Naive
2135 Import a module and alias it Naive
2136 Find out when a course was created and the nationality of the teacher Naive
2137 Print out SMS verification code Naive
2139 print format outputs course information Naive
2140 The number of the two numbers in the list whose sum is equal to n Naive
2141 Determine if a string is uppercase and the consecutive characters are not repeated Naive
2142 Replace the elements in a string Naive
2143 Implementing a shopping cart program Easy
2145 Exception Handling Naive
2146 Implement Decorator with Parameters Naive
2147 Implement an API to Access User Data Easy
2148 Implement User Login API Medium
2153 Implement an API to Check User's Login Status Easy
2155 Implement User Signup API Medium
2156 Implement User Logout API Easy
2157 Print Welcome to LintCode! Java Naive
2158 Custom Exceptions Easy
2159 Printing strings by splicing Java Naive
2160 Print "Hello Java" Java Naive
2161 Implement a Class Dog Inherit from Animal Medium
2162 Filter Users by Email Easy
2163 Realize age-based determination of adulthood Java Naive
2164 Pass or fail according to the score Java Naive
2165 Calculate the values of 1+2+3+... +n values Java Naive
2166 Simple addition, subtraction, multiplication and division Java Naive
2167 Get or Create a User Object Naive
2168 Printable Trigonometric NIne NIne Multiplication Table Java Naive
2169 Three by three generation of data Medium
2170 Read file contents Naive
2171 Django Rest Framework Setup (Bug Fix) Naive
2172 Implement User Login API (Bug Fix I) Easy
2173 Implement User Signup API (Bug Fix) Naive
2174 Query the number of 'your' words in the file Naive
2175 Rounding Java Naive
2176 Find the maximum value of an array Java Naive
2177 Implement User Login API (Bug Fix II) Easy
2178 Iterators and Fibonacci series Easy
2180 Comparing the size of two numbers Naive
2181 Iterator and an even series Easy
2182 Calculate the sum of all positive integers up to and including n that are divisible by 3 Java Naive
2183 Determine the student's achievement range based on the student's achievement level Java Naive
2184 Implement User Signup API (Bug Fix II) Easy
2185 Count the number of times an element appears in the list Naive
2186 Calculate the factorial of n Naive
2187 Combining and sorting lists (one) Naive
2188 Get the element with index 1 Java Naive
2189 Check the age of teachers and sort in ascending order Naive
2190 Select nationality from teacher between 20 and 25 who is not from China or UK Easy
2191 Query information about teachers over n years old Naive
2192 Query teacher information by email (Django) Naive
2193 Query the information of the teacher whose id is 1 Easy
2194 Query the first few data Naive
2195 Query teacher information whose specified field is empty Naive
2196 Query teacher information of a given nationality Naive
2197 Query information about teachers who are not older than the specified age and are not of the specified nationality Easy
2198 Query all the information of the teacher Naive
2199 Remove empty lines from files Naive
2200 Calculate all leap years from 1949 to n Java Naive
2201 Get the element whose index is the last digit Java Naive
2202 Calculate Sum (Python version) Naive
2203 Get the length of the string Java Naive
2204 The remainder of a partial function to divide two positive integers Easy
2205 Binary to decimal conversion Naive
2206 Get the sum of the lengths of all strings in the string array Java Naive
2207 Filter out all odd numbers Medium
2208 Create objects, assign values to object properties and print Java Naive
2209 Create subclass objects and print data using parent class methods Java Easy
2211 Judge the number of palindrome Naive
2212 Write assignment methods and print methods for object properties Java Naive
2216 String summing, repeated output, slicing Naive
2226 Determine if the specified character is present in the string Naive
2227 Bit arithmetic shift left by three bits (Java version) Java Naive
2228 Slicing and Splicing Naive
2229 Find the length, maximum value and minimum value of a tuple Naive
2231 Implementing the area calculation method Java Naive
2232 Print the food that cats and dogs like to eat Java Easy
2240 Update string Naive
2241 Get the millisecond value of the specified date Java Easy
2242 Print book information Java Easy
2244 Print work content Java Naive
2246 Polymorphic way to call drawing methods Java Naive
2247 decision odd or even Naive
2248 Calculate the number of days of a person's birth Java Easy
2249 Implement the methods of the Pig and Dog classes Java Easy
2250 The absolute value of an integer Naive
2251 Print the name and number information of three objects Java Naive
2252 Judgment Results Naive
2253 Print the characteristics of spring, summer, autumn and winter Java Naive
2254 Get the length of the string after removing spaces Java Naive
2256 Replace the contents of a string Java Easy
2257 Determining whether a number is prime or not Naive
2258 Find the largest prime number backwards Naive
2259 Calculate Sum (Java version) Java Naive
2260 List slicing with step Naive
2261 Delete elements in the list Naive
2262 Splicing and copying of lists Naive
2263 string splicing Naive
2264 Convert upper and lower case letters in a string Naive
2265 Find the maximum and minimum values of the elements in a tuple Naive
2266 Swap Two Integers (Java version) Java Naive
2267 Find The Maximum Of Three Numbers (Python version) Naive
2268 Get the attributes of a bull Java Naive
2269 Swap Two Integers (Python version) Naive
2270 Integer Arithmetic (Java version) Java Naive
2271 Integer Arithmetic (Python version) Naive
2272 Find The Maximum Of Three Numbers (Java version) Java Naive
2273 Sequential Output (Python version) Naive
2274 First Python Code: Print Hello World Naive
2275 Sequential Output (Java version) Java Naive
2276 Modify and delete elements in the dictionary Naive
2277 Calculate the sum of all values in the dictionary Naive
2278 Access to student information Java Naive
2279 Reverse Integer Order (Python version) Naive
2281 Merge dictionary Naive
2282 Circular Perimeter (Python version) Naive
2283 Circular Perimeter (Java version) Java Naive
2284 Judge The Multiple Of 3 And 5 (Python version) Naive
2286 Find the greatest common divisor (Python version) Naive
2287 Judge The Multiple Of 3 And 5 (Java version) Java Naive
2288 ASCII Code Of The Character (Python version) Naive
2289 ASCII Code Of The Character (Java version) Java Naive
2290 Find the greatest common divisor (Java version) Java Naive
2291 Splicing and copying of tuple Naive
2311 Rounding a string number Java Naive
2312 Combine the keys and values of the dictionary into a new list Easy
2313 Print the character represented by the Plum, Orchid and Bamboo Java Naive
2314 List modification, addition and deletion of elements Python Naive
2315 Judge the triangle (Python version) Naive
2316 Judgment Triangle (Java Edition) Java Naive
2317 Take A Square Root (Python version) Naive
2318 Using Anonymous Internal Classes Java Naive
2319 List nesting Naive
2320 Take A Square Root (Java version) Java Naive
2321 Hit rate rating (Python version) Naive
2322 Delete the content at the specified position in the string Java Easy
2323 Hit rate rating (Java version) Java Naive
2324 Output String In Reverse Order (Python version) Naive
2325 Output string in reverse order (Java version) Java Naive
2326 Determining whether an integer is a daffodil number Java Naive
2327 Finding The Distance Between Two Points In Rectangular Coordinate System (Python version) Naive
2328 Operations between sets Naive
2329 Finding The Distance Between Two Points In Rectangular Coordinate System (Java version) Java Naive
2330 Calculate the time after x seconds Naive
2331 Find the length, maximum value and minimum value of list Naive
2332 Calculate Factorial (Python Edition) Naive
2333 Print matrix (Python version) Naive
2334 Calculate factorial (Java Edition) Java Naive
2335 Find all the daffodils (Python version) Naive
2336 Case conversion of letters in strings Java Easy
2337 Set containment Naive
2338 Using custom exceptions Java Naive
2339 Judging Leap Year (Java version) Java Naive
2340 Count the number of lowercase letters (Python version) Naive
2341 Find the number of lowercase letters (Java version) Java Naive
2342 The sum of the main diagonal elements (Python version) Naive
2343 Judge Whether It Is A Complete Number (Python version) Naive
2344 Determine whether it is a perfect number (Java version) Java Naive
2345 Movement distance calculation (Python version) Naive
2346 Movement distance calculation (Java version) Java Naive
2347 Use of Static Code Blocks Java Naive
2348 Output Yanghui Triangle (Python version) Naive
2349 Count the number of different characters in a string Java Easy
2350 Judging Leap Year (Python version) Naive
2351 Splicing Two Strings (Python version) Naive
2352 Splicing Two Strings (Java version) Java Naive
2353 Generate a dictionary of perfect squares Naive
2354 Odd sum and even sum (Java Edition) Java Naive
2355 Odd Sum And Even Sum (Python Edition) Naive
2356 Print nine-nine multiplication table (Python version) Naive
2357 Exchange within an array (Python version) Naive
2358 Exporting prime numbers Java Naive
2359 Print nine-nine multiplication table (Java version) Java Naive
2360 Find all the daffodils (Java version) Java Naive
2361 The sum of the main diagonal elements (Java version) Java Naive
2362 Count the number of elements consisting of pure numbers and pure letters from the specified list separately Naive
2363 Split the string according to the line boundary character and find the longest line Easy
2364 Output the nth prime number Naive
2365 Calculate the sum of the array (Python version) Naive
2366 Calculate the sum of the array (Java version) Java Naive
2367 Array sort (Python version) Naive
2368 Array sort (Java version) Java Naive
2369 Using the final keyword Java Naive
2370 Dictionary key value swap Naive
2371 Converts a specified temperature from Fahrenheit to Celsius Naive
2372 break Out Of Loop (Python version) Naive
2373 break out of the loop (Java version) Java Naive
2374 Bug fix for final keyword Java Naive
2375 Judge the power of two(Java Edition) Java Naive
2376 Determine the number of echoes Java Naive
2377 Determine The Power Of 2 (Python version) Naive
2378 final variables are immutable Java Naive
2379 Connect list elements (Python version) Naive
2380 Create an ArrayList collection and add data Java Naive
2381 Exchange in an array (Java version) Java Naive
2382 Can drink at most a few bottles of wine (Python version) Naive
2383 Headerised strings Naive
2384 Bug fix for static keyword Java Naive
2385 Find a To The Power Of b (Python version) Naive
2386 Find a To The Power Of b (Java version) Java Naive
2387 Find the most expensive item Naive
2389 Removing duplicate numbers Java Naive
2390 Complete the string determination as required Naive
2391 Create a HashSet collection and add data Java Naive
2392 Iterate over the key-value pairs in the print dictionary Naive
2393 Iterating through an ArrayList collection Java Naive
2394 Print matrix (Java version) Java Naive
2395 Count the number of occurrences of a string Naive
2396 Generator matrix Naive
2397 List comprehension Naive
2398 Output integers in reverse order (Java version) Java Naive
2399 List merge and sort (two) Naive
2400 Create a HashMap set and add data Java Naive
2401 Letter transformation (Python version) Naive
2402 Letter Transformation (Java Edition) Java Naive
2403 Outputs the Key and Value of all data in the HashMap collection Java Naive
2404 Removing duplicate elements and sorting Java Naive
2405 String replacement Naive
2406 String de-duplication and order assurance Java Naive
2407 Calculate the value of a + aa + aaa + aaaa Naive
2408 String character sorting Java Naive
2409 Create a dictionary with the specified sequence and values Naive
2410 Delete the last key-value pair of the dictionary Naive
2411 Print the number of days contained in each month Java Naive
2412 continue To Continue The Loop (Python version) Naive
2413 continue To Continue The Loop (Java version) Java Naive
2414 Print prime numbers (Python version) Naive
2415 Looking for missing numbers (Java version) Java Naive
2416 N threads to achieve quick sort Hard
2417 Count how many numbers are in the string Java Naive
2418 Bit arithmetic shift left by three bits (Python version) Naive
2419 Output the elements of the set in reverse order Java Naive
2420 Looking for missing numbers (Python version) Naive
2422 Find the position index of a substring in a string Java Naive
2423 Calls to private variables Java Naive
2424 Output Yanghui Triangle (Java version) Java Naive
2425 Calculate the number of folds of paper Java Naive
2426 Print prime numbers (Java version) Naive
2427 Implement the Tweet Model Easy
2428 Start 2 threads to print interleavly 1-n Medium
2429 Calculate how long since the tweet was posted Easy
2430 Implement the Friendship Model Easy
2433 3 threads interleavly print decreasing numbers n - 1 Medium
2434 Define composite index and default ordering Easy
2435 Get User Posted Tweets Easy
2436 Two threads interleavly print numbers and letters Medium
2437 Implement API to create new tweet Easy
2438 n threads print 1-m Medium
2439 Start 2 threads to print "Hello" and "World" respectively Medium
2442 Print ABC interleavly Medium
2443 Get All following Users Easy
2444 3 threads to print n groups Medium
2445 Implement Follow User API Medium
2446 Get All followers Easy
2447 Implement an API to Unfollow a User Medium
2448 N threads to achieve merge sort Hard
2449 Sleep Sort Easy
2450 Start the thread to print hello world Naive
2451 Use 10 threads to calculate the sum of 1-n Medium
2452 Main thread and sub thread print interleavly Medium
2453 Use N threads to calculate the sum of the array Medium
2454 N threads to find the number with most factors Easy
2455 Define Comment Model Medium
2456 Implement an API to Created Comment Medium
2457 Implement an API to Update Comments Medium
2458 Implement an API to Delete Comment Medium
2459 Nth highest player height Medium
2460 Player Height Ranking1 Medium
2462 Design Bounded Blocking Queue Medium
2463 Define the NewsFeed Model Medium
2464 Implement an API to Get NewsFeeds Easy
2465 Data shuffle based on Sklearn Naive
2466 List deduplicate Naive
2467 Design Bounded Blocking Stack Medium
2468 Fanout New Tweets to NewsFeed Medium
2469 Implement an API to Get Comment List Medium
2470 Implement a single tweet API with comments Medium
2471 Design Thread Safe Linked List Medium
2472 Adding elements to a set Naive
2473 Design Thread Safe Hash Table Medium
2474 Define The Like Model Medium
2475 Implement an API to Create Like Hard
2476 Implement an API to Dislike Medium
2477 Inject like information into the comment API Medium
2478 Implement an API to Send Comment Notification Medium
2479 Implement an API to Send Like Notification Medium
2491 Implement an API to get the number of unread messages Easy
2492 Implement data normalization based on Sklearn Naive
2493 Implement data standardization based on Sklearn Naive
2494 Summation of a tuple at a specified position Naive
2495 Calculate F1 score of data based on Sklearn Naive
2496 4 threads modify the same variable Easy
2497 Deposit and Withdraw Money Easy
2498 Set update operation Naive
2499 Height of players appearing consecutively Medium
2500 Highest scoring player in the team Medium
2501 Implement the One Click Read API Easy
2502 Design Thread Safe Array List Medium
2503 Implement a thread-safe counter Easy
2504 Log recording with multithreading Easy
2505 Calculate accuracy score based on Sklearn Naive
2506 Remove the Invalid Parentheses JavaScript Easy
2507 Recognition hand writing digital images based on KNN algorithm Easy
2508 Recognition hand writing digital images based on Logistic Regression algorithm Easy
2509 Find a number that appears only once in the list Easy
2510 Recognition hand writing digital images based on Multi-layer Perceptron Easy
2511 Code constructor to initialize student class instance Easy
2513 Remove Folder Naive
2514 Copy folder Naive
2515 The only number that exists Java Naive
2518 Series Data Type Creation Naive
2519 DataFrame Data Type Creation Naive
2520 pandas index Naive
2521 pandas Hierarchical Index Naive
2522 pandas data merge Naive
2523 Hand writing digital image recognition based on MNIST dataset Medium
2524 Group Aggregation Easy
2525 basic_attribute_and_overall_situation_query Naive
2526 Pandas Data Read Naive
2527 Pandas Missing value handling Naive
2528 data_analysis_for_mean_value Naive
2529 Removing duplicate values from dataset using Pandas Naive
2530 Intercept even numbers from a given sequence Naive
2531 Index of matrix elements Easy
2532 numpy mathematical calculation method practice Easy
2533 Create an 8x8 chess board matrix Easy
2534 Create a dtype to represent the color (RGBA) Easy
2535 Calculate the matrix by subtracting the average of each row Naive
2536 Create a numpy array Naive
2538 Based on SimpleImputer class to do missing value processing Naive
2539 Fill missing values using KNN Easy
2540 Your First Git Commit Easy
2541 one-hot code Naive
2542 Update Linghu Chong's email Naive
2543 Implement dimensionality reduction based on sklearn Naive
2544 Insert information about Feng Qingyang Naive
2545 Implement K-means clusting algorithm based on sklearn Naive
2546 Find outliers in the data using the absolute median difference algorithm (MAD) Medium
2547 Query all information in the teachers table Naive
2548 Update Southern Emperor's email Naive
2549 Create a new folder Naive
2550 Find outliers in the data using density-based local outlier factor algorithm (LOF) Medium
2551 Normalizing data using z-score Easy
2552 Normalize the data using min-max standardization Easy
2553 Delete Linghu Chong's message Naive
2554 Insert information about Chong Xu Naive
2555 Create a new file Naive
2556 Update the age of Linghu Chong Naive
2557 Insert information about Xie Xun Naive
2558 H2O generation Medium
2559 Withdrawal of age update for Linghu Chong Naive
2560 Undo the insertion of Xie Xun's message Naive
2564 Create a Trigger "before_teachers_insert" Easy
2565 Create a Trigger "before_teachers_update" Easy
2566 Logistic regression doing dichotomous classification for cancer prediction Naive
2567 Delete the Trigger "before_teachers_insert" Easy
2568 Delete the Trigger "before_teachers_update" Easy
2569 Normative courses table data insert Medium
2570 New data processing of recruitment information statistics table Medium
2571 Text classification based on plain Bayesian algorithm Naive
2572 New data trigger message alert Medium
2573 Backup New Data Trigger Medium
2574 Copying documents Naive
2575 Normative courses table data update Medium
2576 Update data processing of recruitment information statistics table Medium
2577 Backup Update Data Trigger Medium
2578 Update data trigger message alert Hard
2579 Calling the sklearn API to implement linear regression to predict home prices in California Easy
2580 yh_Split dataset (do not move) Naive
2581 Automatic backup when deleting teacher information Medium
2582 Moving documents Naive
2583 Delete data trigger message alert Medium
2584 shows model loss in predicting boston house prices with cross-validation for ridge regression Easy
2585 Moving folders Naive
2586 Delete document Naive
2587 Associated processing when deleting teachers table information (I) Easy
2588 Calculate the mean square error loss of the linear regression model Easy
2589 Calculate precision score of data based on Sklearn Naive
2590 Calculate recall score of data based on Sklearn Naive
2591 Manual implementation of linear regression completes California home price forecasting model Medium
2592 Associated processing when deleting teachers table information (II) Medium
2593 Show current directory Naive
2594 Access to the specified directory Naive
2595 Implement SGD based on sklearn Naive
2596 compute binary cross-entropy with log_loss Naive
2597 List file directories and file names Naive
2598 Show all triggers for teachers table Easy
2599 Compare the differences between the two documents Naive
2600 Manual implementation of Principal Component Analysis (PCA) to complete data dimensionality reduction Medium
2601 Calculate R2 score for model based on sklearn Naive
2602 Handwritten KNN algorithm for digital image recognition Medium
2603 Checking disk usage Naive
2604 View the space occupied by a file Naive
2605 View username and group name Naive
2606 View user ID and group ID Naive
2607 Handwritten K-means algorithm for clustering of iris dataset Hard
2608 Compare the two documents Naive
2609 Manual implementation of Logistic Regression to complete the Binary Classification Problem Medium
2610 Implement SVM classifier based on sklearn Easy
2611 Determine if two arrays are equal Java Naive
2612 Build a decision tree for prediction based on sklearn API Easy
2613 Submit a document amendment Naive
2614 Find the perimeter and area of a rectangle Java Easy
2615 Print the student's personal information Java Easy
2616 Insert Kansas information into the teacher table Easy
2617 View the current transaction isolation level of the database Easy
2618 Convert characters in a string to ASCII code Java Easy
2619 Track and submit document changes Naive
2620 View the self-incrementing locking pattern for MySQL databases Easy
2621 Implementing an API to Update Notification Status Medium
2622 Print information about cows and horses Java Easy
2623 Find eligible files in a directory (i) Easy
2624 Birds eat worms Java Naive
2625 Whether two strings are equal Java Naive
2626 Add files to the stage Naive
2627 Troubleshoot the current database table locks and view the table lock analysis Easy
2628 Find eligible files in a directory (ii) Easy
2629 Manual implementation of decision tree algorithm - complete calculation of Gini index function Medium
2630 Find eligible files in a directory (iii) Medium
2631 Array string conversion Java Easy
2632 Intercept the string at the specified position Naive
2633 Troubleshoot the current database row locks and view row lock analysis Easy
2634 Defining the UserProfile model Easy
2635 The use of optimistic locks and pessimistic locks (I) Medium
2642 Get user configuration Medium
2643 Create file link (I) Naive
2644 Drinking milk for breakfast Java Naive
2645 Viewing the contents of a file using a different binary Naive
2646 Implement decision tree algorithm - complete information entropy calculation function Medium
2647 Implement the function of uploading user avatar Medium
2648 View file contents using different decoding methods Naive
2649 Define the tweet picture model Medium
2650 Implement the Tweet API Medium
2651 Implement the function of determining whether you have followed or not Medium
2652 Implement friend relationship paging function Medium
2653 Display String (i) Naive
2654 Put a line lock on the data 'id = 3' Easy
2655 Array replacement Java Naive
2656 Create file link (II) Naive
2657 Zhang San's self-introduction Java Naive
2658 Display personalized information of users Medium
2659 Implement the function of modifying user nickname Medium
2660 git Branch Renaming Naive
2661 What day of the week is this Java Easy
2662 Merge files Naive
2663 Check Pet Information Java Naive
2664 Recognizing SQL Views (I) Naive
2665 Recognizing SQL Views (II) Easy
2666 Ridge regression based on sklearn to predict boston house prices Easy
2667 Plotting lines based on Matplotlib Naive
2668 Create and switch branches Naive
2669 Modify the last commit Easy
2670 I am Kang Kang Java Naive
2671 Backtrack and recommit commit Easy
2672 Image reading and saving based on Matplotlib Easy
2673 Subplotting based on Matplotlib Easy
2674 Creating a simple SQL View (I) Medium
2675 Date format conversion Java Naive
2676 Creating a simple SQL View (II) Medium
2677 Advanced plot() function - Customizing the output style Easy
2678 Split a large file into multiple small files Naive
2679 Display String (ii) Naive
2680 Predictive classification of iris dataset based on sklearn's stacking algorithm Easy
2681 Display String (iii) Naive
2682 The Nth day of the year Java Naive
2683 Zhang San's MySQL Learning Path (I) Hard
2684 Making a cup of coffee Java Easy
2685 Zhang San's MySQL Learning Path (II) Hard
2686 Bar plotting based on Matplotlib Easy
2687 Scatter plotting based on Matplotlib Easy
2689 Redefining the teachers view Easy
2690 Exception Capture I Java Naive
2691 View file details Naive
2692 Count the total number of students taught by each faculty member Easy
2693 File creation preset permissions Naive
2694 Print the upper and lower case alphabet Java Naive
2695 Retrieves the specified items of a document by different delimiters Naive
2696 Cache and restore across branches Naive
2697 Find a compliant document (i) Naive
2698 Find a compliant document (ii) Naive
2699 Exception Capture II Java Naive
2700 Update Linghu Chong's age by view Easy
2701 Remove documents Easy
2702 Delete Linghu Chong's teacher data by view Easy
2703 Decision making using adaboost algorithm based on sklearn API Naive
2704 Zhang San's MySQL Learning Path (III) Hard
2705 Show view in the current database Easy
2706 Renaming views (I) Easy
2707 Renaming views (II) Easy
2708 Drop View (I) Easy
2709 Drop View (II) Easy
2710 Copy Files (i) Naive
2711 Move documents Naive
2712 View the type of command Naive
2713 Find the location of the command Naive
2714 Implementation of gradient boosting decision tree (GBDT) for breast cancer disease prediction Medium
2715 View Processing Algorithm Merge Easy
2716 View Processing Algorithm TEMPTABLE Easy
2717 Serialized attention status Easy
2718 Define friend relationship pager Easy
2719 Execute expression Naive
2720 Creating a view that ensures consistency (I) Easy
2721 Creating a view that ensures consistency (II) Easy
2722 Implement Random Forest based on sklearn Easy
2723 Showing the definition of a view Easy
2724 Cascade checking of views Easy
2725 Local checking of views Easy
2726 File View Naive
2727 Compare document differences by column (ii) Naive
2728 Implement tweet paging function Medium
2729 Writing to a file Easy
2730 Delete file contents Easy
2731 Inject like information and comment information into the Tweet API Medium
2732 View submission history Naive
2733 Replacement and presentation of document content in rows Easy
2735 Realize the paging function of new things Medium
2736 Document content sorting(i) Naive
2737 Document content sorting(ii) Naive
2738 Document content sorting(iii) Naive
2739 Remove duplicate lines in the file Naive
2740 Expression evaluation (I) Naive
2741 Tagging Easy
2742 Expression evaluation (II) Naive
2743 Expression evaluation (III) Naive
2744 Cache people who are following Medium
2745 Use the cache to determine whether the function has been followed Medium
2746 Formatted view of historical submission records Naive
2747 Caching user information Medium
2748 Implement user cache invalidation function Medium
2750 Define a general cache helper Medium
2751 Convert a file from lowercase to uppercase Naive
2752 Word counts Naive
2753 Word counts(ii) Naive
2754 Set command aliases Naive
2755 View System Information Naive
2756 View itinerary Naive
2757 Setting up the shell Naive
2758 Input and output redirection Naive
2759 The range of Integer values Java Easy
2760 Understanding SQL Procedures (I) Easy
2761 Understanding SQL Procedures (II) Easy
2793 Execute the command in the variable Naive
2794 Execute the command in the variable(ii) Naive
2795 Set Environment Variables Naive
2796 Shell Resource Settings Naive
2797 Setting and deleting variables Naive
2798 Aop Simplify Log Easy
2799 Creating a procedure for inserting data in bulk Medium
2800 Zhang San's MySQL Learning Path (IV) Hard
2801 Delete Stored Procedure (I) Easy
2802 Delete Stored Procedure (II) Easy
2803 Compressed files Naive
2804 Unzip the file Naive
2805 Cache user personalized configuration information Easy
2806 MySQL Stored Procedure IN Parameters I Easy
2807 MySQL Stored Procedure IN Parameters II Easy
2808 MySQL Stored Procedure OUT Parameters I Easy
2809 MySQL Stored Procedure OUT Parameters II Easy
2810 MySQL Stored Procedure INOUT Parameters I Easy
2811 MySQL Stored Procedure INOUT Parameters II Easy
2812 MySQL Stored Procedure Variables I Easy
2813 Find the sum of even numbers 1 - 100 Java Naive
2814 ASCII code corresponding characters (Java version) Java Naive
2815 How long your savings will last Java Naive
2816 Han Xin points out the troops Java Naive
2817 Interconversion of doubles and strings Java Easy
2818 Find the sum of the inverse diagonals of an array Java Easy
2819 Determining prime numbers Java Easy
2820 Sum of small numbers Java Easy
2821 The disappearing number 6 Java Naive
2822 Truncate the character with subscript 5 Java Naive
2823 What Triangle is this Java Easy
2824 Encrypted love letters Java Easy
2825 Determine if strings are equal Java Naive
2826 Friends of Number 2 Java Easy
2827 Change string Java Naive
2828 Splice strings and change to uppercase Java Naive
2829 Simple cell phone number verification Java Naive
2830 Disappearing strings Java Naive
2831 Inverted strings Java Naive
2832 A simple check of the mailbox format Java Easy
2833 Compliant figures Java Naive
2834 Simple string splitting Java Easy
2835 Find the maximum and minimum values of two numbers Java Naive
2836 Find the maximum value Java Naive
2837 Copy the specified element Java Naive
2838 Randomly generated numbers Java Naive
2840 Simple string matching and replacement Java Easy
2841 Please connect the charger Java Naive
2842 The constructor without parameters (I) Java Naive
2843 The constructor without parameters (II) Java Naive
2844 Superfly Java Naive
2845 Custom Exceptions - Java Java Naive
2846 Reasonable permissions Java Easy
2847 Teachers giving lessons to students Java Easy
2848 Refining the right class Java Naive
2849 Inverted arrays Java Naive
2850 The constructor with parameters (I) Java Naive
2851 New friends at the zoo Java Naive
2852 Additional properties and methods of the Student class Java Naive
2853 Common singleton pattern Class Java Easy
2854 Custom annotations Easy
2855 The constructor with parameters (II) Java Easy
2856 Create Person abstract class Java Easy
2857 Abstract Factory Pattern Medium
2858 The wheels of the car Java Naive
2859 Student implement 2 interfaces Java Naive
2860 Implementing the interface Java Easy
2861 Ride payment prompt (Interpreter Pattern) Medium
2862 Calling internal classes Java Naive
2863 Are the two people with the same name Java Easy
2864 A week of rest day (I) Java Easy
2865 Anonymous internal classes Java Naive
2866 A week of rest day (II) Java Easy
2867 A week of rest day (III) Java Easy
2868 All objects Java Naive
2869 Managing Books Java Naive
2870 Variables of the interface Java Naive
2871 Initialize class properties Java Naive
2872 static Loaded code block Java Naive
2873 Check code (I) Java Easy
2874 Local Internal Classes Java Naive
2875 Program results Java Naive
2876 Sum of extreme differences Java Naive
2877 Delete the smallest value in the set Java Naive
2878 3 and multiples of 3 Java Naive
2879 Output all key-value pairs in a Map Java Naive
2880 AddData to a Map Java Easy
2881 The largest number Java Easy
2882 Honor roll for final exams Java Easy
2883 A general commodity class Java Medium
2884 A week of rest day (IV) Java Easy
2885 Roster of classes Java Naive
2886 Sorting a Map Java Naive
2887 Student set with double sort Java Easy
2888 Arrays merge Java Naive
2889 Summation of arrays Java Naive
2890 Alphabetical order Java Naive
2891 Filtering elements in a collection Java Naive
2892 Accessing elements Java Naive
2893 Arrays with duplicate numbers Java Easy
2894 Order by frequency Java Medium
2895 Sum of two numbers II Java Naive
2896 Use of generic classes Java Naive
2897 Intercepting data using Queue Java Easy
2898 Intercepting data using Stack Java Easy
2899 LinkedList implementation of string reversal output Java Naive
2900 LinkedList Removal of duplicate elements Java Naive
2901 Array Copy Java Naive
2902 Seating in order on the bus Java Medium
2903 Use of generalized arrays Java Easy
2904 Use of Generic Types Java Easy
2905 Upper and lower bounds for generic types Java Naive
2906 Thread-safe List Java Easy
2907 A week of rest day (V) Medium
2908 Replace Kth string Naive
2909 Reverse String in K-Group Easy
2910 Add a first level title Hello LintCode! HTML Naive
2911 Adding class names HTML Naive
2912 Production submission section HTML Naive
2913 Colours in HTML CSS Naive
2914 Writing an Ordered List HTML Naive
2915 Adding CSS Styles CSS Naive
2916 Writing an Unordered List HTML Naive
2917 [Exercise] Logical operations between two variables Naive
2918 Formatting Old Poems CSS Naive
2919 Integer Operations 2 Naive
2920 Get the input data and print it Naive
2921 Completing the Navigation Menu with Tab Nesting HTML Naive
2922 Make a Menu CSS HTML Easy
2923 Define a list Naive
2924 Define strings and numbers and print them Naive
2925 Define a tuple Naive
2926 Retrieve the month in the date string and add one(I) Naive
2927 Number Classification Naive
2928 Finding Common Multiples Naive
2929 Find the most expensive items (list version) Naive
2930 Writing a list to a file Naive
2931 Read the dictionary from the file and modify it Naive
2932 Print Student Grade Point Average Naive
2933 Print student grade point average (exception version) Easy
2934 Read csv file and modify Easy
2935 The Disappearing Box CSS Naive
2936 Handling Overflow Content CSS Naive
2937 The rightmost 1 of a binary number Medium
2938 Complete the chain table class (I) Medium
2939 Complete the chain table class (II) Easy
2940 Byte string and string interconversion Naive
2942 Blocking people on the blacklist Naive
2943 Making a Name Entry Box HTML Naive
2945 Modifying the Style of In-Line Phrases CSS Naive
2946 Positioning Sub-packagings CSS Naive
2947 Determine if it is in the list Naive
2948 Discounts for members Naive
2949 Find the number that appears an odd number of times Easy
2950 Check if it is the same object Naive
2951 Find a right-angled side of a right triangle Naive
2953 Implementing Button Styles Naive
2955 Getting to know python deep and shallow copies Naive
2956 Determine if a discount is available Naive
2957 Setting the Type of the Input Element Naive
2958 Fetch the numbers in the list for operation Naive
2959 Find the average of the maximum values in each list Easy
2960 Define a function Naive
2961 Formatting Ancient Poems II CSS Naive
2962 Initializing CSS CSS Naive
2963 Colourful Input Boxes CSS Naive
2965 Modifying the Mouse Cursor Style CSS Naive
2966 Adding Text and Box Shadows Naive
2967 Colourful Buttons CSS Naive
2968 Text Omitted if Out of Width CSS Easy
2971 Making of the Heart CSS Easy
2972 Modify Opacity Naive
2973 Relationship Selectors CSS Naive
2974 The Relationship Selector II CSS Naive
2975 Stylized Buttons CSS Easy
2976 Adding a Progress Bar CSS HTML Naive
2977 The Link Jump HTML Naive
2978 Modifying the Outer Shape of a Figure CSS Naive
2980 Setting the Margins of Boxes II CSS Naive
2981 Different Rounded Corners CSS Naive
2982 The Tenth Row that Never Goes CSS Naive
2983 The Cool Button CSS Naive
2984 Moving Black Blocks Naive
2986 Units in CSS CSS Naive
2987 Selecting dishes HTML Naive
2988 Units in CSS II Naive
2989 Choose a Favourite Course HTML Easy
2990 The Cool Box CSS Naive
2991 Adjusting Paragraph Size CSS Naive
2992 Revising the Outline of a Paragraph Naive
2993 Making a Christmas Tree CSS Naive
2994 Modifying the Alignment of Paragraphs CSS Naive
2995 Choose Your Favorite Animal Naive
2996 Making a Student Information Form CSS HTML Naive
2997 Modifying Case CSS Naive
2998 Making a Horizontal Navigation Bar CSS HTML Easy
2999 Making a Vertical Navigation Bar Easy
3000 Making a Horizontal Navigation Bar (II) CSS Naive
3001 Modifying Character Spacing Naive
3002 Modifying Paragraph Indentations CSS Naive
3003 The Dazzling Text CSS Naive
3004 Revising Poetry Row High CSS Naive
3005 Labels in Colour CSS Naive
3006 Making a Note CSS Naive
3007 Selecting Brother Headings and Paragraphs CSS Naive
3008 The Box That Got Bigger CSS Naive
3009 Crossing the Street CSS Naive
3010 Modifying the Boldness of Fonts Naive
3012 Making CSS Box Model Easy
3013 The Many Ways to Distribute Left and Right CSS Easy
3014 Making a Horizontal Navigation Bar III CSS Easy
3015 Changing the Point of Origin CSS Naive
3017 Modifying Text Size CSS Naive
3018 Setting the Background Pattern Style CSS Naive
3019 Modify Picture Style CSS HTML Naive
3020 The Cutting Box CSS Naive
3021 Choosing a Favourite Critter II HTML Easy
3022 Making the Dice CSS Easy
3023 The Extra Long Word CSS Naive
3026 Modifying Boxes Borders CSS Naive
3027 Tables for Colour Explosion CSS Naive
3029 Modifying the Background Origin CSS Naive
3044 Designing a Search Box CSS HTML Easy
3048 Making a Login Form CSS HTML Easy
3061 Basic structure of HTML HTML Naive
3062 Print Hello World! PHP Naive
3063 HTML Page Title Tag HTML Naive
3064 Data Portfolio PHP Naive
3065 Basic syntax of HTML HTML Naive
3067 Easy Calculator PHP Naive
3068 Exchange variables PHP Naive
3069 Custom text content tags span HTML Naive
3070 Progressive data PHP Naive
3071 Image tags img HTML Naive
3072 Horizontal line tag hr HTML Naive
3073 Hello world! Naive
3074 Parity judgment PHP Naive
3075 Determining leap years (PHP version) PHP Naive
3077 Paragraph tag p HTML Naive
3078 Write route and view Naive
3081 Standard input and output statements Naive
3082 Branching Statements Naive
3083 Custom Tag div HTML Naive
3084 Loop statements Naive
3085 Introduction to Functions Naive
3086 Month days judgment PHP Naive
3087 Frame tag iframe HTML Naive
3088 Score Leveling PHP Naive
3089 Variable definition exercise Naive
3090 Common Structured Element Tags HTML Easy
3091 Maximal Convention (php version) PHP Naive
3092 Summation (PHP version) PHP Naive
3093 Han Xin Points (PHP version) PHP Naive
3094 Calculate the area of a circle Easy
3095 Is it a letter? Easy
3096 Is it a leap year? Easy
3097 The sum of numbers that are not divisible by 7 PHP Naive
3098 Button tag button HTML Naive
3099 Implement Polls application Model Easy
3100 Text field tag textarea HTML Naive
3101 Make the model modifiable in admin Naive
3102 Binary digits of an integer Easy
3103 Write URLconf Easy
3104 Drop-down menu tag select HTML Naive
3105 Take absolute value Easy
3106 Label wrap input box label HTML Naive
3107 Write URLconf (Bug Fix) Naive
3108 Movie Rating Easy
3109 Customize background management Naive
3110 String Splicings PHP Naive
3111 String case conversion PHP Easy
3112 Printable Ninety-Nine Multiplication Table Easy
3113 HTML Character Entities HTML Naive
3114 Word Searchs PHP Naive
3115 Wrong echo string PHP Naive
3116 Invalid IP address PHP Naive
3118 HTML colors HTML Naive
3119 HTML & CSS HTML Naive
3120 Thread Control Logic Medium
3121 Adaptive Access between Company A and Company B Easy
3122 String escaping PHP Naive
3123 Normative words PHP Naive
3124 Knock Seven Easy
3125 Repeat Strings PHP Naive
3126 Guess the number Easy
3127 How many times is 2 squared? Easy
3132 Summation PHP Naive
3133 Remove empty folders Naive
3134 Is it a prime number? Easy
3135 CalculatorⅠ Easy
3136 CalculatorⅡ Easy
3137 Split tuple Naive
3138 Number of occurrences of the element in the tuple Naive
3139 The largest element in the set Naive
3140 Set Operations Naive
3141 The sum of the elements in the set whose absolute value is less than 10 Naive
3142 The number of different values in the dictionary Naive
3143 Dictionary size after merging Naive
3144 Replace list elements according to dictionary Naive
3145 Creating arrays PHP Naive
3146 First and last numbers PHP Naive
3147 Ordered arrays PHP Naive
3148 Using lambda function to construct quadratic polynomial with one variable Naive
3149 Add the two numbers together Naive
3150 Array length PHP Naive
3151 Most frequently occurring words PHP Naive
3152 String conversion PHP Naive
3153 Deck Generation Medium
3154 Discounted Travel with Transit Card Naive
3155 package file Naive
3156 Area of a circle (macro definition) Naive
3157 Unzip the zip file Naive
3158 Using lambda function to get sum of list Easy
3159 True or False Number PHP Naive
3160 Middle Numbers PHP Naive
3161 Summation of integer arrays PHP Naive
3162 Sort members by age Naive
3163 The maximum value of the array PHP Naive
3164 Rename the imported file with the same name Naive
3165 Pointer exercise Naive
3166 Sum the absolute values of two numbers (Python version) Naive
3167 Alternating sums (Python version) Naive
3168 Addition, subtraction, multiplication and division two numbers Naive
3169 Collatz conjecture (Python version) Naive
3170 Find the first integer whose square is greater than n Naive
3171 Find the number in 1 - n that can be divided by x Naive
3172 Sum of multiples of 7 with final number of 2 (Python version) Naive
3173 Adding two numbers (pointer and reference) Easy
3174 The number of elements whose value is a multiple of its index (Python version) Naive
3175 Number of tuples that form a triangle Naive
3176 Print the noon time point of the corresponding date Naive
3177 Definition of functions PHP Naive
3178 Exchange of numbers PHP Naive
3179 Parameter Printing PHP Naive
3180 String flipping PHP Naive
3181 Anonymous functions PHP Naive
3182 Callback functions PHP Naive
3183 Ten years later PHP Naive
3184 Date Formatting PHP Naive
3185 Get the timestamp of the date PHP Naive
3186 Definition of Class PHP Naive
3187 Student Information PHP Naive
3188 Create constructor PHP Naive
3189 Define a subclass PHP Naive
3190 Save student information PHP Easy
3191 Definition of abstract classes PHP Naive
3192 Implementation of the interface PHP Naive
3193 Delete message prompt PHP Naive
3194 Calling a method that does not exist PHP Naive
3195 Confirming the identity of the class PHP Naive
3196 Division operations PHP Naive
3197 Custom Exception Classes PHP Naive
3198 Invalid objects PHP Naive
3199 Customized error handling PHP Naive
3200 Accessing arrays Naive
3201 Accessing two-dimensional arrays Naive
3202 Array traversal Naive
3203 Accessing character arrays Easy
3204 Character arrays to size Easy
3205 String-to-Size Easy
3206 String Slicing Easy
3207 Adding elements Naive
3208 String splitting Easy
3209 Moving fruit Medium
3210 Train access Medium
3211 Queue Naive
3212 Is there this student? Naive
3213 Define the student structure Naive
3214 Read student information Easy
3215 Pointer traversal of arrays Easy
3220 Define The Student Model I Naive
3227 Define The Book Model II Naive
3228 Output ASCII values of input lowercase letters in sequence Naive
3229 Define The Book Model I Naive
3230 Find duplicate mailboxes Naive
3231 Define The Student Model II Naive
3232 Implement Class application Model Naive
3239 Update the table contents and output the updated table Naive
3240 Count the number of Letters of each type Java Easy
3241 Query the number of students for the web course Naive
3242 Print "LintCode" Java Naive
3243 Equivalent String Easy
3244 Implement Band application Model Easy
3247 Design Time Class Naive
3263 Sort Student models Naive
3267 Design Circle Related Methods Naive
3269 Set joint constraints on Student model Naive
3278 Format Book read count Naive
3279 Show book name and author Naive
3285 Print Encapsulated Student Information Naive
3298 Inherit and Print Student Information Naive
3300 Using the Transportation Method Naive
3324 Tree-shaped Relationships within the Company Easy
3327 Fast Food Ordering System Medium
3329 PC Peripheral Accessor (Java) Medium
3330 Fitness Course Builder (Java) Easy
3331 Contracting of Actors Easy
3332 Different Drinking Experience Naive
3333 Singleton Pattern Using Enumerations (Java) Easy
3334 Package Clone Naive
3336 Multimedia Playback Adapter (Java) Medium
3338 File System Design Medium
3340 Tool to Determine If String Is Empty Naive
3341 Restore Game Archive Easy
3344 Using the Shape Factory to Calculate the Area of Various Shapes OOD Easy
3345 Initialize the Person Class Naive
3349 Initialize the Animals Class (C++) Naive
3350 Abstract Factory for Making Milk Tea (Java) Medium
3354 Application of Synchronized - Alternate Printing Easy
3356 Equivalent String (Python) Easy
3357 Print Student Information Naive
3364 Application of Keyword Volatile - Printing Incremental Numbers Easy
3365 Rewrite the model save() method Easy
3366 Implement Restaurant application Model Easy
3367 Create Model - Custom Manager Easy
3368 Sorting String With Lambda Expression Java Easy
3369 Create Model - Add Model Method Easy
3370 Create a User Object Naive
3371 Modify all book information Easy
3372 Query the book information of the specified author name Easy
3373 Check the author of books and sort in descending order Easy
3374 Query the information of the first n books in the order of reading times Easy
3375 Query the student information according to the score range and sort it in ascending order Easy
3376 Check the information of students whose test score are greater than or equal to N times the general score Easy
3377 Wrapping of Animals Class (C++) Naive
3378 Sort student information in ascending order by total score Easy
3379 Designing the Person Class Naive
3380 Check the information of students whose general score and test score are greater than or equal to 60 Easy
3381 Check the information of students whose general score or test score are greater than or equal to a specific value Easy
3382 Update the course total score of all students Easy
3383 Update and query the student information of the specified conditions Medium
3384 Delete student information according to sno Easy
3385 Delete associated model objects according to keywords Hard
3386 Query the information of students passing the course Hard
3387 Query the information of n students who passed the course but whose scores are reciprocal Easy
3390 Custom Templates Easy
3392 Control Smart Curtains (Java) Easy
3395 Menu of Various Permissions OOD (Java) Medium
3398 Shared Website Templates (Java) Medium
3400 Perimeter and Area of a Square Naive
3402 Linked List Instantiation Easy
3404 Online Coffee Shopping Platform Medium
3405 Web Server Configuration Whitelist Easy
3407 Fire Alarm Easy
3408 Queue Instantiation Easy
3410 Game Progress Saving (Python) Easy
3411 Mediator of Housing Rental (Java) Medium
3412 Approval Chain for Leave Requests (Java) Medium
3413 Digital Wallet Medium
3414 Issuance and Execution of Tasks Medium
3417 Analog Guitar Easy
3418 Pharmacy Business System Medium
3419 Elevator Controller Easy
3421 A Design of Student Course Selection System (Java) Hard
3422 Brush and Shape Medium
3423 Beverage Refilling Business Easy
3424 Python Implementation Stack Naive
3425 Multi-person Self-introduction Easy
3426 Output of The Number of Objects Naive
3427 Furniture Placement Problem Easy
3428 Company Leave Request System Medium
3429 Recommended Merchants (Java) Hard
3430 A Design of Unmanned Vending Supermarket (Java) Hard
3431 Designing Company Organization Structure Medium
3432 Restaurant Ordering System Hard
3433 Stock Inquiry Client Easy
3435 Determining the Relationship between Circle and Point Easy
3436 The Magician Exchanges the Poker in both Hands Easy
3437 Performance of Multiple Instruments Naive
3438 Warehouse Management System Hard
3439 Serialized User Model and Group Model Naive
3440 Implementation of User Model and Group Model ViewSet Naive
3441 Registered User and Group ViewSet Routing Naive
3442 Serialized Blog Model Easy
3443 Serialized Blog Model II Easy
3444 Implement Blog View Function Easy
3445 Implement Blog View Function II Easy
3446 Automatic Coffee Maker Easy
3447 Implement Blog View Class Easy
3448 Implement Blog View Class II Easy
3449 Automatic Coffee Maker II Easy
3450 Implement Blog application view class Medium
3451 Stock of Vending Machines Easy
3452 Add Blog Application View Class Permissions Hard
3453 Create Hyperlink Path Medium
3454 Fruit Packaging Factory Easy
3455 Iterator for Linked List Easy
3456 Receptionist at Pet Store Easy
3457 Create a Thread to Splice Words Naive
3458 Print Hello LintCode in Thread Naive
3459 Stop a Running Thread Naive
3460 Determine If a Thread Is Stopped Naive
3461 Creation of Multitasking Threads Easy
3462 Thread’s Working Ways Naive
3463 Putting Thread to Sleep Naive
3464 Custom Thread Wrapper Easy
3465 Force a New Thread to Execute Naive
3466 Changing the Priority of a Thread Naive
3467 Create a Daemon Thread Naive
3468 Thread Passing Parameters Naive
3469 Transfer Thread Ownership Naive
3470 Swap Thread Naive
3471 Data Concurrent Modification Protection Naive
3472 Remove the Deadlock Relationship Naive
3473 Timeout Attempt on Mutex Naive
3474 Box for Storing Data from Different Threads Easy
3475 Incrementing and Modifying Values in an Array at the Same Time Easy
3476 Print Values in Two Arrays Alternately Easy
3477 1 Producer and 1 Consumer Easy
3478 Create a Thread Pool to Perform a Specified Amount of Tasks Easy
3479 Shutdown the Thread Pool Naive
3480 Complete Array Python Easy
3481 Find the Index of the Maximum Value Easy
3482 The Only Thread-safe Call Naive
3483 Create an Asynchronous Task Naive
3484 Create a Custom Thread Pool to Execute Tasks Easy
3485 Asynchronous Result Sharing Naive
3486 Customizing Thread Pool Rejection Policy Easy
3487 Custom Asynchronous Results Naive
3488 Print in Order Easy
3489 Convert Asynchronous Tasks Naive
3490 Synchronization of Workers' Tasks Easy
3491 Synchronization of Workers' Tasks II Easy
3492 Design of the Spinlock Naive
3493 Longest Subarray Medium
3494 Simulation of Station Gates Easy
3495 Family Fruit Medium
3496 Family Fruit II Hard
3497 Print Values of Two Arrays Alternately II Easy
3498 Supply Products Medium
3499 Supply Products II Medium
3500 Dividing Line Easy
3501 The best sales Easy
3502 Implementation of CountDownLatch Easy
3503 Supply Products III Medium
3504 Implementation of Semaphore Easy
3505 Product Combination Medium
3506 Implementation of Barrier Easy
3507 Compute and Remove Spaces from a String Naive
3508 First-Come First-Served Easy
3509 Implementation of CyclicBarrier Medium
3510 Display Full Name Synchronously Easy
3511 Implementing a Message Pop-Up Component Easy
3512 Implementation of the TODO List Medium
3513 Implementation of the TODO List II Hard
3514 Shortest Job First Medium
3515 Highest Response Ratio Next Medium
3516 Shortest Remaining Time Next Hard
3517 Implementation of Parallel Search Algorithm Medium
3518 Solving for roots and powers of positive integers Naive
3519 Average Salary Naive
3520 Implementation of Parallel Bubble Sort Algorithm Easy
3521 Control Style Scopes Naive
3522 Hello Vue Naive
3523 Vue Class Bindings Naive
3524 Render All List Elements Naive
3525 Vue Style Bindings Naive
3526 Dependency Injection (Provide) Easy
3527 Dependency Injection (Injection) Easy
3528 Transition Effect Medium
3530 Process List And Render Naive
3531 Vue Conditional Rendering Naive
3532 Vue Conditional Rendering II Naive
3533 Design Data Self-Increment And Self-Decrement Buttons Naive
3534 Teleport Medium
3535 Use of Text Interpolation Naive
3536 Insert Raw HTML Code Naive
3537 Make Form Text Box Naive
3538 Sort and Filter Grid Component Implementation Hard
3539 Make Form Selection Box Naive
3540 Bind Click Event to Buttons Naive
3541 Tree View Component Implementation Hard
3542 Non-Negative Prefix Sum Easy
3543 Dynamically Bind Class Names for Paragraphs Naive
3544 Exam Progress TypeScript Easy
3545 Vue Props Easy
3546 Dynamically Bind Styles for Paragraphs Naive
3547 Matrix Override Medium
3548 Vue Slots Naive
3549 Vue Emits Easy
3550 Vue Dynamic Components Easy
3551 Vue Global Component Registration Easy
3552 Interesting Triples Medium
3553 Importing Components Naive
3554 Default & Named Slots Easy
3555 Defining and Using Components Naive
3556 Scoped Slots Easy
3557 Counting Button Clicks Easy
3558 Vue Local Component Registration Easy
3559 Customized Subcomponents Easy
3560 Bind Keyboard Events to Input Boxes Naive
3561 Form Input Bindings Naive
3562 Single-File Component Naive
3563 Component Two-Way Binding Naive
3564 List and Object Traversal Naive
3565 Polling Display Title Naive
3566 Local Registration of Components Naive
3567 Global Registration of Components Naive
3568 Provide Naive
3569 Inject Naive
3570 Computed Naive
3571 Named Slot Naive
3572 Slot Naive
3573 Transition Style Binding Naive
3574 List Transition Animation Naive
3575 Dynamic Components Naive
3576 Add Data to Button Component Naive
3577 Define Properties of the Component Naive
3578 KeepAlive Naive
3579 Caching Components and Switching Between Them Easy
3580 Implementing Content Polling Button Naive
3581 External Teleport Naive
3582 A Fake Counter Naive
3583 Watch Property Naive
3584 Observing the Impact of Quantity Changes in the Shopping Cart Easy
3585 Calculate Average and Array Sum Naive
3586 Virtual DOM Naive
3587 Render Functions Naive
3588 Priority of Rendering Options Naive
3589 Use ref(), toRef(), and unref() to Manage Data Easy
3590 Count the Number of Characters Naive
3591 Basic Use of Mixins Easy
3592 Customized Commands Naive
3593 Record List Element Log Easy
3594 Implementation of Multiple Delete Function in Table Easy
3595 Deserialize Binary Tree Medium
3596 Order Volume for Each Time Period Medium
3597 Lowest Common Ancestor IV Hard
3598 Sum of Two Linked Lists TypeScript Easy
3599 Remove Repeated Letters Medium
3600 Fix Binary Search Tree Medium
3601 Cumulative Number TypeScript Medium
3602 The Largest Sum Divisible by Three TypeScript Medium
3603 Longest Nice Subarray Medium
3604 The Minimum String After Swapping Medium
3605 Shift 2D Grid Easy
3606 Query the Middle Node ID Medium
3607 Number of Students Passing the Exam Easy
3608 Overall Approval Rate of Friend Requests Medium
3609 Who Has the Most Friends Medium
3610 Courses Taken by All Students Easy
3611 My Best Friend Medium
3612 Product Prices for the Specified Date Medium
3613 Search For Students Ranked Second to Fifth Easy
3614 Check the Referrals of Customers Easy
3615 Data Median Medium
3616 Combined Course Transcripts Easy
3617 Replacement of Seats for Two Consecutive Persons Medium
3618 Time-Consuming Top Three Tasks Easy
3619 Project Subtask Hard
3620 Logger Rate Limiter Easy
3621 Fixed Point TypeScript Easy
3622 Read N Characters Given Read4 Easy
3623 Sum of Digits in the Minimum Number TypeScript Easy
3624 Count Substrings with Only One Distinct Letter TypeScript Easy
3625 Index Pairs of a String Medium
3626 How Many Apples Can You Put into the Basket TypeScript Easy
3627 Find All The Lonely Nodes TypeScript Easy
3628 Highest Five Subject Average TypeScript Easy
3629 Intersection of Three Sorted Arrays TypeScript Easy
3630 Two Sum Less Than Target TypeScript Easy
3631 Remove Vowels From String TypeScript Easy
3632 Delete n Nodes After m Nodes of a Linked List TypeScript Easy
3633 Missing Number In Arithmetic Progression TypeScript Easy
3634 Largest Unique Number TypeScript Easy
3635 Largest Subarray Length k TypeScript Easy
3636 Array Transformation TypeScript Easy
3637 Problematic Sensor Easy
3638 Single-Row Keyboard TypeScript Easy
3639 Check If a String Be Split into Value-Equal Substrings TypeScript Easy
3640 Hexspeak TypeScript Easy
3641 Sport Plan Performance TypeScript Easy
3642 Counting Elements TypeScript Easy
3643 Whether the Array Is a Consecutive Array TypeScript Easy
3644 Check If a Number is Majority Element in an Array TypeScript Easy
3645 Perform String Shifts TypeScript Easy
3646 Count Houses on a Circular Street Easy
3647 Design Compressed String Iterator Java Easy
3648 Reverse Words in a String IV Medium
3649 Find the Sum of Two Nodes of Two BST TypeScript Medium
3650 Absolutely Continuous Numbers TypeScript Medium
3651 Number of Connected Components in an Undirected Graph TypeScript Medium
3652 Shortest Way to Form String TypeScript Medium
3653 Meeting Scheduler Medium
3654 Toss Coins Medium
3655 Minimize Rounding Error to Meet Target Medium
3656 Design Snake Game Medium
3657 All Paths Can Pass from Start to End Medium
3658 Website Crawler Medium
3659 Design Phone Directory Java Easy
3660 Competition Leaderboard Medium
3661 Missing Element in Sorted Array Medium
3662 Design Hit Counter Java Easy
3663 Diameter of an Undirected Tree Medium
3664 Longest Repeating Substring Medium
3665 Inorder Successor in BST II Medium
3666 Campus Bikes II Hard
3667 Encode Number TypeScript Medium
3668 Bracket Expansion TypeScript Medium
3669 Smallest Common Region Medium
3670 The Earliest Moment When Everyone Become Friends Medium
3671 Replace the Synonyms in the Sentence Medium
3672 Connecting Cities With Minimum Cost Medium
3673 Parallel Courses Medium
3674 Printing Immutable Linked List in Reverse Order Python Medium
3675 Minimum Swaps to Group All 1's Together TypeScript Medium
3676 Analyze User Website Visit Pattern Medium
3677 Design File System Medium
3678 Delete Interval Medium
3679 Shortest Distance to Target Color TypeScript Medium
3680 Before and After Puzzle TypeScript Medium
3681 Delete Nodes of Tree Medium
3682 Knight Shortest Path IV Medium
3683 Columns with at Least a One on the Leftmost Side Medium
3684 Find Smallest Common Element in All Rows TypeScript Medium
3685 First Unique Integer Medium
3686 Diameter of N-Ary Tree Medium
3687 Check If an Array Is a Valid Sequence TypeScript Medium
3688 Strings Differ by One Character TypeScript Medium
3689 Put Boxes Into the Warehouse Medium
3690 Clone Binary Tree II Medium
3691 Dot Product of Two Sparse Vectors Python Easy
3692 Put Boxes Into the Warehouse II Medium
3693 Clone N-branch Tree Medium
3694 Nonnegative Subarray TypeScript Easy
3695 Nonnegative Subarray II TypeScript Medium
3696 Inverse Subarray TypeScript Easy
3697 Find Subscripts TypeScript Easy
3698 The Leftmost Smaller Number TypeScript Easy
3699 Clear the String Medium
3701 Find Nearest Right Node in Binary Tree Python Medium
3702 Maximum Sum Queries Hard
3703 Count Number of Rectangles Containing Each Point Medium
3704 Count Good Triplets in Array Hard
3705 Minimum Moves to Make Array Complementary Medium
3706 Number of Pairs That Satisfy the Condition TypeScript Hard
3707 Corporate Flight Bookings TypeScript Medium
3708 Minimum Number of Increments on Subarrays to Form a Target Array Hard
3709 Minimum Number of Visited Lattices in a Matrix Hard
3710 Design Most Recently Used Queue Medium
3711 Delete the Problem Node in a Binary Tree Medium
3712 Maximum Subarray Sum After Squaring An Element TypeScript Medium
3713 Change the Root of a Binary Tree Medium
3714 Buildings With an Ocean View TypeScript Easy
3715 Lowest Common Ancestor V Medium
3716 Longest Perfect Palindromic Subsequence Medium
3717 The Number of Distinct Substrings Medium
3718 Sort Features by Popularity TypeScript Medium
3719 Shortest Path to Get Bubble Tea TypeScript Medium
3720 Count Pairs of Equal Substrings With Minimum Difference Medium
3721 Maximum Number of Study Groups Medium
3722 Calculate the Distance Between Two Nodes in a Binary Tree TypeScript Medium
3723 Remove Duplicates from Unsorted List II TypeScript Medium
3724 Distinct Numbers in Each Subarray TypeScript Medium
3725 Calculate the Depth of BST Based on the Order of Insertions Medium
3726 Rotting Oranges TypeScript Medium
3727 Shortest Path in the Maze Medium
3728 Longest Word With All Prefixed Medium
3729 Implement Trie II Python Medium
3730 Product of Two Run-Length Encoded Arrays TypeScript Medium
3731 Minimize Product Sum of Two Arrays TypeScript Medium
3732 Minimum Path Cost in a Maze Medium
3733 Count Pairs in Two Arrays TypeScript Medium
3734 Cutting Ribbons TypeScript Medium
3735 Bash Game II Medium
3736 Kth Smallest Subarray Sum Medium
3737 Find Maximum Values Among All Minimum Values of Subarrays Medium
3738 Longest Common Subsequence Between Sorted Arrays Medium
3739 Binary Searchable Numbers in an Unsorted Array Medium
3740 Calculate the Number of Nodes Equal to Sum of Child Nodes TypeScript Medium
3741 Widest Pair of Indices With Equal Range Sum TypeScript Medium
3742 Maximum Number of People Can Be Caught in a Game TypeScript Easy
3743 Smallest Greater Multiple Made of Two Digits TypeScript Medium
3744 Calculate the Average Height of Buildings in Each Region Medium
3745 Brightest Position on Street TypeScript Medium
3746 Count the Number of Subarrays Where 1 Appears More than 0 TypeScript Medium
3747 Maximum Alternating Subarray Sum Medium
3748 Number of Spaces the Robot Can Clean Medium
3749 Reorder Absolute Value Linked List TypeScript Medium
3750 Minimum Cost of Dividing the Sentence into Lines Medium
3751 Number of Equal Count Substrings TypeScript Medium
3752 Number of Substrings That Start and End with the Same Letter Easy
3753 Maze of Confusion Medium
3754 Largest Even Sum of Subsequences with Length K Medium
3755 Minimum Cost to Reach City With Discounts Medium
3756 Number of Unique Flavors Remaining After Sharing K Candies Medium
3762 First C Code: Print Hello World Naive
3763 C Variable Definition Exercise Naive
3764 C Variable Definition Exercise II Naive
3765 Print "Hello World" with Quotation Mark Naive
3766 A+B in Different Binaries Naive
3767 Print File Path Naive
3768 Determine Odd or Even Number Naive
3769 Judging Leap Year (C version) Naive
3770 Processing Data Naive
3771 Reverse Integer (C version) Easy
3772 Find all the daffodils (C version) Naive
3773 Print nine-nine multiplication table (C version) Easy
3774 Determining Prime Number Easy
3775 Find the Greatest Common Divisor (C version) Easy
3776 Finding the Least Common Multiples (C version) Easy
3777 Output Data by Format Naive
3778 First String Containing Only Letters Easy
3780 Output The Month According to The Number Naive
3781 Read Data on Demand Easy