/LeetCode

Solutions and resources for Leetcode problems.

Primary LanguageC++GNU General Public License v3.0GPL-3.0

LeetCode

Solutions and resources for LeetCode problems from a C++ begginer.

Note

Symbol Meaning
♠ fundamental
♣ complexity
♦ regular pattern
¤ not seen yet

LeetCode Algorithm

No. Title Solution Difficulty Add Data
1 Two Sum C++ Easy 2017/03/02
2 Add Two Numbers C++ Medium 2017/03/02
3 Longest Substring Without Repeating Characters C++ Medium 2017/03/02
4 Median of Two Sorted Arrays C Hard 2017/03/02
5 Longest Palindromic Substring C++ Medium 2017/03/03
7 Reverse Integer C++ Easy 2017/03/02
8 String to Integer(atoi) C++ Medium 2017/03/04
10 Regular Expression Matching C++ Hard 2017/03/09
11 Container With Most Water C++ Medium 2017/03/09
13 Roman to Integer C++ Easy 2017/03/02
14 Longest Common Prefix C++ Easy 2017/03/09
15 3Sum C++ Medium 2017/03/10
17 Letter Combinations of a Phone Number C++ Medium 2017/03/11
19 Remove Nth Node From End of List C++ Medium 2017/03/11
20 Valid Parentheses C++ Easy 2017/03/11
21 Merge Two Sorted Lists C++ Easy 2017/03/11
22 Generate Parentheses C++ Medium 2017/03/11
23 Merge k Sorted Lists C++ Hard 2017/03/12
26 Remove Duplicates from Sorted Array C++ Easy 2017/03/12
28 Implement strStr C++ Easy 2017/03/12
29 Divide Two Integers C++ Medium 2017/03/14
33 Search in Rotated Sorted Array C++ Medium 2017/03/16
34 Search for a Range C++ Medium 2017/03/16
36 Valid Sudoku C++ Medium 2017/03/17
38 Count and Say C++ Easy 2017/03/17
41 First Missing Positive C++ Hard 2017/03/17
42 Trapping Rain Water C++ Hard 2017/03/18
44 Wildcard Matching C++ Hard 2017/03/19
46 Permutations C++ Medium 2017/03/20
48 Rotate Image C++ Medium 2017/03/20
49 Group Anagrams C++ Medium 2017/03/21
50 Pow(x, n) C++ Medium 2017/03/21
53 Maximum Subarray C++ Easy 2017/03/21
54 Spiral Matrix C++ Medium 2017/03/22
55 Jump Game C++ Medium 2017/03/22
56 Merge Intervals C++ Medium 2017/03/23
66 Plus One C++ Easy 2017/03/02
242 Valid Anagram C++ Easy 2017/03/21
268 Missing Number C++ Easy 2017/03/17
515 Find Largest Value in Each Tree Row C++ Medium 2017/03/05
62 Unique Paths C++ Medium 2017/03/25
69 Sqrt C++ Easy 2017/03/26
70 Climbing Stairs C++ Easy 2017/03/26
73 Set Matrix Zeroes C++ Medium 2017/03/27
75 Sort Colors C++ Medium 2017/03/27
76 Minimum Window Substring♣♠♠ C++ Hard 2017/03/27
78 Subsets C++ Medium 2017/03/29
79 Word Search C++ Medium 2017/03/29
88 Merge Sorted Array C++ Easy 2017/03/29
84 Largest Rectangle in Histogram C++ Hard 2017/03/30
101 Symmetric Tree♠ C++ Easy 2017/03/30
91 Decode Ways♣ C++ Medium 2017/03/31
94 Binary Tree Inorder Traversal♠ C++ Medium 2017/03/31
98 Validate Binary Search Tree♠ C++ Medium 2017/03/31
102 Binary Tree Level Order Traversal♠ C++ Medium 2017/03/31
103 Binary Tree Zigzag Level Order Traversal C++ Medium 2017/03/31
104 Maximum Depth of Binary Tree C++ Easy 2017/03/31
105 Construct Binary Tree from Preorder and Inorder Traversal♣ C++ Medium 2017/04/01
108 Convert Sorted Array to Binary Search Tree C++ Easy 2017/04/01
116 Populating Next Right Pointers in Each Node♠ C++ Medium 2017/04/01
118 Pascal's Triangle C++ Easy 2017/04/01
121 Best Time to Buy and Sell Stock C++ Easy 2017/04/01
24 Swap Nodes in Pairs♠ C++ Medium 2017/04/03
95 Unique Binary Search Trees II♣ C++ Medium 2017/04/03
96 Unique Binary Search Trees C++ Medium 2017/04/03
100 Same Tree C++ Easy 2017/04/03
122 Best Time to Buy and Sell Stock II♣ C++ Easy 2017/04/03
125 Valid Palindrome C++ Easy 2017/04/03
63 Unique Paths II♠ C++ Medium 2017/04/03
64 Minimum Path Sum C++ Medium 2017/04/03
51 N Queens♠ C++ Hard 2017/04/04
52 N Queens II C++ Hard 2017/04/04
169 Majority Element C++ Easy 2017/04/04
215 [Kth Largest Element in an Array]&spade;215 C++ Medium 2017/04/04
240 Search a 2D Matrix II C++ Medium 2017/04/04
241 Different Ways to Add Parentheses♣ C++ Medium 2017/04/04
61 Rotate List C++ Medium 2017/04/05
82 Remove Duplicates from Sorted List II♠ C++ Medium 2017/04/05
83 Remove Duplicates from Sorted List C++ Easy 2017/04/05
86 Partition List♠ C++ Medium 2017/04/05
92 Reverse Linked List II♣ C++ Medium 2017/04/05
141 Linked List Cycle♠ C++ Easy 2017/04/05
142 Linked List Cycle II♠ C++ Medium 2017/04/05
206 Reverse Linked List C++ Easy 2017/04/05
203 Remove Linked List Elements♠ C++ Easy 2017/04/05
39 Combination Sum♠ C++ Medium 2017/04/06
40 Combination Sum II C++ Medium 2017/04/06
47 Permutations II♣ C++ Medium 2017/04/06
60 Permutation Sequence♦ C++ Medium 2017/04/06
77 Combinations C++ Medium 2017/04/06
90 Subsets II C++ Medium 2017/04/06
58 Length of Last Word C++ Easy 2017/04/07
67 Add Binary C++ Easy 2017/04/07
120 Triangle C++ Medium 2017/04/07
139 Word Break♣ C++ Medium 2017/04/07
152 Maximum Product Subarray♣ C++ Medium 2017/04/07
198 House Robber♠ C++ Easy 2017/04/09
213 House Robber II C++ Medium 2017/04/09
221 Maximal Square C++ Medium 2017/04/09
263 Ugly Number C++ Easy 2017/04/09
264 Ugly Number II♣ C++ Medium 2017/04/09
279 Perfect Squares♣ C++ Medium 2017/04/09
300 Longest Increasing Subsequence♦ C++ Medium 2017/04/09
303 Range Sum Query Immutable C++ Easy 2017/04/09
322 Coin Change C++ Medium 2017/04/09
304 Range Sum Query 2D Immutable C++ Medium 2017/04/10
309 Best Time to Buy and Sell Stock with Cooldown♠♣ C++ Medium 2017/04/10
136 Single Number♠ C++ Easy 2017/04/10
338 Counting Bits♦ C++ Medium 2017/04/11
343 Integer Break♦ C++ Medium 2017/04/11
357 Count Numbers with Unique Digits♦ C++ Medium 2017/04/11
368 Largest Divisible Subset♣ C++ Medium 2017/04/11
106 Construct Binary Tree from Inorder and Postorder Traversal C++ Medium 2017/04/12
107 Binary Tree Level Order Traversal II♠ C++ Easy 2017/04/12
110 Balanced Binary Tree♠ C++ Easy 2017/04/12
111 Minimum Depth of Binary Tree♠ C++ Easy 2017/04/12
112 Path Sum♣ C++ Easy 2017/04/12
113 Path Sum II C++ Medium 2017/04/12
109 Convert Sorted List to Binary Search Tree♠ C++ Medium 2017/04/13
138 Copy List with Random Pointer♠ C++ Medium 2017/04/13
89 Gray Code♣ C++ Medium 2017/04/18
93 Restore IP Addresses♣ C++ Medium 2017/04/18
131 Palindrome Partitioning C++ Medium 2017/04/18
216 Combination Sum III C++ Medium 2017/04/18
401 Binary Watch C++ Easy 2017/04/18
16 3Sum Closest C++ Medium 2017/04/20
18 4Sum♠ C++ Medium 2017/04/20
27 Remove Element C++ Easy 2017/04/20
208 Implement Trie♠ C++ Medium 2017/04/20
211 Add and Search Word Data structure design♠ C++ Medium 2017/04/20
374 Guess Number Higher or Lower C++ Easy 2017/04/20
375 Guess Number Higher or Lower II♣ C++ Medium 2017/04/20
421 Maximum XOR of Two Numbers in an Array♣ C++ Medium 2017/04/20
526 Beautiful Arrangement C++ Medium 2017/04/20
31 Next Permutation♦ C++ Medium 2017/04/20
35 Search Insert Position♠ C++ Easy 2017/04/20
59 Spiral Matrix II♠ C++ Medium 2017/04/20
74 Search a 2D Matrix♣ C++ Medium 2017/04/20
167 Two Sum II Input array is sorted C++ Easy 2017/04/20
376 Wiggle Subsequence♣ C++ Medium 2017/04/24
377 Combination Sum IV♣ C++ Medium 2017/04/24
392 Is Subsequence C++ Medium 2017/04/24
413 Arithmetic Slices C++ Medium 2017/04/24
416 Partition Equal Subset Sum♠♣ C++ Medium 2017/04/24
467 Unique Substrings in Wraparound String♦♣ C++ Medium 2017/04/24
486 Predict the Winner♠♣ C++ Medium 2017/04/24
494 Target Sum♠ C++ Medium 2017/04/24
516 Longest Palindromic Subsequence C++ Medium 2017/04/24
80 Remove Duplicates from Sorted Array II♣ C++ Medium 2017/04/26
119 Pascals Triangle II♠ C++ Easy 2017/04/26
153 Find Minimum in Rotated Sorted Array♠♣ C++ Medium 2017/04/26
217 Contains Duplicate C++ Easy 2017/04/26
219 Contains Duplicate II♦ C++ Easy 2017/04/26
523 Continuous Subarray Sum♦ C++ Medium 2017/04/26
530 Minimum Absolute Difference in BST C++ Easy 2017/04/26
06 ZigZag Conversion C++ Medium 2017/05/02
81 Search in Rotated Sorted Array II♠ C++ Medium 2017/05/02
143 Reorder List C++ Medium 2017/05/02
151 Reverse Words in a String C++ Medium 2017/05/02
160 Intersection of Two Linked Lists♠ C++ Easy 2017/05/02
162 Find Peak Element C++ Medium 2017/05/02
234 Palindrome Linked List C++ Easy 2017/05/02
344 Reverse String C++ Easy 2017/05/02
345 Reverse Vowels of a String C++ Easy 2017/05/02
383 Ransom Note C++ Easy 2017/05/02
434 Number of Segments in a String C++ Easy 2017/05/02
09 Palindrome Number♠ C++ Easy 2017/05/04
189 Rotate Array♠ C++ Easy 2017/05/04
202 Happy Number♠ C++ Easy 2017/05/04
204 Count Primes♠♠ C++ Easy 2017/05/04
205 Isomorphic Strings♠ C++ Easy 2017/05/04
237 Delete Node in a Linked List♠ C++ Easy 2017/05/04
328 Odd Even Linked List C++ Medium 2017/05/04
445 Add Two Numbers II♠ C++ Medium 2017/05/04
464 Can I Win♣♣ C++ Medium 2017/05/04
474 Ones and Zeroes♣ C++ Medium 2017/05/04
43 Multiply Strings♣ C++ Medium 2017/05/07
114 Flatten Binary Tree to Linked List♠ C++ Medium 2017/05/07
117 Populating Next Right Pointers in Each Node II♣ C++ Medium 2017/05/07
129 Sum Root to Leaf Numbers♠ C++ Medium 2017/05/07
144 Binary Tree Preorder Traversal♠ C++ Medium 2017/05/07
145 Binary Tree Postorder Traversal♠ C++ Hard 2017/05/07
209 Minimum Size Subarray Sum♣ C++ Medium 2017/05/07
415 Add Strings♠ C++ Easy 2017/05/07
71 Simplify Path♠ C++ Medium 2017/05/17
127 Word Ladder♠♣ C++ Medium 2017/05/17
147 Insertion Sort List♠ C++ Medium 2017/05/17
148 Sort List♠ C++ Medium 2017/05/17
228 Summary Ranges C++ Medium 2017/05/17
230 Kth Smallest Element in a BST♠ C++ Medium 2017/05/17
290 Word Pattern♠ C++ Easy 2017/05/17
349 Intersection of Two Arrays C++ Easy 2017/05/17
350 Intersection of Two Arrays II♠ C++ Easy 2017/05/17
441 Arranging Coins♦ C++ Easy 2017/05/17
130 Surrounded Regions♠ C++ Medium 2017/06/02
133 Clone Graph♠♠ C++ Medium 2017/06/02
137 Single Number II♠ C++ Medium 2017/06/02
155 Min Stack♠ C++ Easy 2017/06/02
165 Compare Version Numbers♦ C++ Medium 2017/06/02
168 Excel Sheet Column Title♠ C++ Easy 2017/06/02
171 Excel Sheet Column Number♠ C++ Easy 2017/06/02
190 Reverse Bits C++ Easy 2017/06/02
191 Number of 1 Bits♠ C++ Easy 2017/06/02
207 Course Schedule♠♦ C++ Medium 2017/06/02
260 Single Number III♠♠ C++ Medium 2017/06/02
475 Heaters♠&sapdes; C++ Easy 2017/06/02
521 Longest Uncommon Subsequence I C++ Easy 2017/06/02
522 Longest Uncommon Subsequence II♦ C++ Medium 2017/06/02
12 Integer to Roman♦ C++ Medium 2017/06/29
97 Interleaving String♠♠ C++ Hard 2017/06/29
134 Gas Station♣ C++ Medium 2017/06/29
150 Evaluate Reverse Polish Notation C++ Medium 2017/06/29
166 Fraction to Recurring Decimal♣ C++ Medium 2017/06/29
172 Factorial Trailing Zeroes♦ C++ Easy 2017/06/29
173 Binary Search Tree Iterator C++ Medium 2017/06/29
179 Largest Number♠ C++ Medium 2017/06/29
187 Repeated DNA Sequences♠♠ C++ Medium 2017/06/29
199 Binary Tree Right Side View C++ Medium 2017/06/29
200 Number of Islands♠♠ C++ Medium 2017/06/29
201 Bitwise AND of Numbers Range♣ C++ Medium 2017/06/29
210 Course Schedule II♠♣ C++ Medium 2017/06/29
220 Contains Duplicate III♣ C++ Medium 2017/06/29
222 Count Complete Tree Nodes♠ C++ Medium 2017/06/29
223 Rectangle Area C++ Medium 2017/06/29
225 Implement Stack using Queues♠♠ C++ Easy 2017/06/29
226 Invert Binary Tree C++ Easy 2017/06/29
231 Power of Two C++ Easy 2017/06/29
326 Power of Three♠ C++ Easy 2017/06/29
342 Power of Four♠ C++ Easy 2017/06/29
400 Nth Digit♣ C++ Easy 2017/06/29
581 Shortest Unsorted Continuous Subarray♣ C++ Easy 2017/06/29
295 Find Median From Data Stream♠♣ C++ Hard 2017/07/01
480 Sliding Window Median♠♣ C++ Hard 2017/07/01
72 Edit Distance♠♠ C++ Hard 2017/07/06
233 Number of Digit One♣ C++ Hard 2017/07/06
30 Substring with Concatenation of All Words♣♠♠ C++ Hard 2017/07/07
438 Find All Anagrams in a String♠♠ C++ Easy 2017/07/07
212 Word Search II♣♣ C++ Hard 2017/07/14
493 Reverse Pairs♣♣ C++ Hard 2017/07/14
32 Longest Valid Parentheses♠♣ C++ Hard 2017/07/15
572 Subtree of Another Tree♣ C++ Easy 2017/07/15
146 LRU Cache♠♣ C++ Hard 2017/07/20
229 Majority Element II♠♠ C++ Medium 2017/07/20
347 Top K Frequent Elements♠♣ C++ Medium 2017/07/20
460 LFU Cache♣♣ C++ Hard 2017/07/20
123 Best Time to Buy and Sell Stock III C++ Hard 2017/08/30
124 Binary Tree Maximum Path Sum C++ Hard 2017/08/30
149 Max Points on a Line C++ Hard 2017/08/30
235 Lowest Common Ancestor of a Binary Search Tree C++ Easy 2017/08/30
236 Lowest Common Ancestor of a Binary Tree C++ Medium 2017/08/30
315 Count of Smaller Numbers After Self C++ Hard 2017/08/30
327 Count of Range Sum C++ Hard 2017/08/30
402 Remove K Digits C++ Medium 2017/08/30
459 Repeated Substring Pattern C++ Easy 2017/08/30
541 Reverse String II C++ Easy 2017/08/30
542 01 Matrix C++ Medium 2017/08/30
557 Reverse Words in a String III C++ Easy 2017/08/30
561 Array Partition I C++ Easy 2017/08/30
567 Permutation in String C++ Medium 2017/08/30
628 Maximum Product of Three Numbers C++ Easy 2017/08/30