1 |
Two Sum |
Solution |
Easy |
Two Pointer |
2 |
Add Two Numbers |
Solution |
Medium |
|
4 |
Median of Two Sorted Arrays |
Solution |
Hard |
|
5 |
Longest Palindromic Substring |
Solution |
Medium |
|
7 |
Reverse Integer |
Solution |
Easy |
|
9 |
Palindrome Number |
Solution |
Easy |
|
13 |
Roman to Integer |
Solution |
Easy |
|
14 |
Longest Common Prefix |
Solution |
Easy |
|
15 |
3sum |
Solution |
Medium |
|
16 |
3sum Closest |
Solution |
Medium |
|
17 |
Letter Combinations of a Phone Number |
Solution |
Medium |
|
19 |
Remove Nth Node From End of List |
Solution |
Medium |
|
20 |
Valid Parentheses |
Solution |
Easy |
|
21 |
Merge Two Sorted Lists |
Solution |
Easy |
|
22 |
Generate Parentheses |
Solution |
Medium |
|
23 |
Merge k Sorted Lists |
Solution |
Hard |
|
26 |
Remove Duplicates from Sorted Array |
Solution |
Easy |
|
27 |
Remove Element |
Solution |
Easy |
|
28 |
Implement strStr() |
Solution |
Easy |
|
33 |
Search in Rotated Sorted Array |
Solution |
Medium |
|
34 |
Find First and Last Position of Element in Sorted Array |
Solution |
Medium |
|
35 |
Search Insert Position |
Solution |
Easy |
|
38 |
Count and Say |
Solution |
Easy |
|
42 |
Trapping Rain Water |
Solution |
Hard |
|
46 |
Permutations |
Solution |
Medium |
|
47 |
Permutations II |
Solution |
Medium |
|
48 |
Rotate Image |
Solution |
Medium |
|
49 |
Group Anagrams |
Solution |
Medium |
|
51 |
N-Queens |
Solution |
Hard |
|
52 |
N-Queens II |
Solution |
Hard |
|
53 |
Maximum Subarray |
Solution |
Easy |
|
55 |
Jump Game |
Solution |
Medium |
|
58 |
Length of Last Word |
Solution |
Easy |
|
62 |
Unique Paths |
Solution |
Medium |
|
63 |
Unique Paths II |
Solution |
Medium |
|
66 |
Plus One |
Solution |
Easy |
|
67 |
Add Binary |
Solution |
Easy |
|
69 |
Sqrt(x) |
Solution |
Easy |
|
70 |
Climbing Stairs |
Solution |
Easy |
|
73 |
Set Matrix Zeroes |
Solution |
Medium |
|
78 |
Subsets |
Solution |
Medium |
|
80 |
Remove Duplicates from Sorted Array II |
Solution |
Medium |
|
81 |
Search in Rotated Sorted Array II |
Solution |
Medium |
|
82 |
Remove Duplicates from Sorted List II |
Solution |
Medium |
|
83 |
Remove Duplicates from Sorted List |
Solution |
Easy |
|
88 |
Merge Sorted Array |
Solution |
Easy |
|
90 |
Subsets II |
Solution |
Medium |
|
92 |
Reverse Linked List II |
Solution |
Medium |
|
94 |
Binary Tree Inorder Traversal |
Solution |
Medium |
|
98 |
Validate Binary Search Tree |
Solution |
Medium |
|
100 |
Same Tree |
Solution |
Easy |
|
101 |
Symmetric Tree |
Solution |
Easy |
|
102 |
Binary Tree Level Order Traversal |
Solution |
Medium |
|
104 |
Maximum Depth of Binary Tree |
Solution |
Easy |
|
107 |
Binary Tree Level Order Traversal II |
Solution |
Easy |
|
108 |
Convert Sorted Array to Binary Search Tree |
Solution |
Easy |
|
110 |
Balanced Binary Tree |
Solution |
Easy |
|
111 |
Minimum Depth of Binary Tree |
Solution |
Easy |
|
118 |
Pascal's Triangle |
Solution |
Easy |
|
119 |
Pascal's Triangle II |
Solution |
Easy |
|
121 |
Best Time to Buy and Sell Stock |
Solution |
Easy |
|
122 |
Best Time to Buy and Sell Stock II |
Solution |
Easy |
|
125 |
Valid Palindrome |
Solution |
Easy |
|
127 |
Word Ladder |
Solution |
Medium |
|
136 |
Single Number |
Solution |
Easy |
|
139 |
Word Break |
Solution |
Medium |
|
141 |
Linked List Cycle |
Solution |
Easy |
|
142 |
Linked List Cycle II |
Solution |
Medium |
|
143 |
Reorder List |
Solution |
Medium |
|
144 |
Binary Tree Preorder Traversal |
Solution |
Medium |
|
145 |
Binary Tree Postorder Traversal |
Solution |
Hard |
|
146 |
LRU Cache |
Solution |
Medium |
|
148 |
Sort List |
Solution |
Medium |
|
149 |
Max Points on a Line |
Solution |
Hard |
|
151 |
Reverse Words in a String |
Solution |
Medium |
|
155 |
Min Stack |
Solution |
Easy |
|
160 |
Intersection of Two linked Lists |
Solution |
Easy |
|
162 |
Find Peak Element |
Solution |
Medium |
|
167 |
Two Sum II - Input array is sorted |
Solution |
Easy |
|
168 |
Excel Sheet Column Title |
Solution |
Easy |
|
169 |
Majority Element |
Solution |
Easy |
|
171 |
Excel Sheet Column Number |
Solution |
Easy |
|
172 |
Factorial Trailing Zeroes |
Solution |
Easy |
|
175 |
Combine Two Tables |
Solution |
Easy |
|
176 |
Second Highest Salary |
Solution |
Easy |
|
177 |
Nth Highest Salary |
Solution |
Medium |
|
178 |
Rank Scores |
Solution |
Medium |
|
180 |
Consecutive Numbers |
Solution |
Medium |
|
181 |
Employees Earning More Than Their Managers |
Solution |
Easy |
|
182 |
Duplicate Emails |
Solution |
Easy |
|
183 |
Customers Who Never Order |
Solution |
Easy |
|
184 |
Department Highest Salary |
Solution |
Medium |
|
185 |
Department Top Three Salaries |
Solution |
Hard |
|
189 |
Rotate Array |
Solution |
Easy |
|
190 |
Reverse Bits |
Solution |
Easy |
|
191 |
Number of 1 Bits |
Solution |
Easy |
|
196 |
Delete Duplicate Emails |
Solution |
Easy |
|
197 |
Rising Temperature |
Solution |
Easy |
|
198 |
House Robber |
Solution |
Easy |
|
200 |
Number of Islands |
Solution |
Medium |
|
202 |
Happy Number |
Solution |
Easy |
|
203 |
Remove Linked List Elements |
Solution |
Easy |
|
204 |
Count Primes |
Solution |
Easy |
|
206 |
Reverse Linked List |
Solution |
Easy |
|
207 |
Course Schedule |
Solution |
Medium |
|
208 |
Implement Trie (Prefix Tree) |
Solution |
Medium |
https://leetcode.com/articles/implement-trie-prefix-tree/ |
210 |
Course Schedule II |
Solution |
Medium |
|
217 |
Contains Duplicate |
Solution |
Easy |
|
226 |
Invert Binary Tree |
Solution |
Easy |
|
231 |
Power of Two |
Solution |
Easy |
|
232 |
Implement Queue using Stacks |
Solution |
Easy |
|
234 |
Palindrome Linked List |
Solution |
Easy |
|
235 |
Lowest Common Ancestor of a Binary Search Tree |
Solution |
Easy |
|
236 |
Lowest Common Ancestor of a Binary Tree |
Solution |
Medium |
|
237 |
Delete Node in a Linked List |
Solution |
Easy |
|
238 |
Product of Array Except Self |
Solution |
Medium |
|
239 |
Sliding Window Maximum |
Solution |
Hard |
|
240 |
Search a 2D Matrix II |
Solution |
Medium |
|
242 |
Valid Anagram |
Solution |
Easy |
|
262 |
Trips and Users |
Solution |
Hard |
|
263 |
Ugly Number |
Solution |
Easy |
|
264 |
Ugly Number II |
Solution |
Medium |
|
268 |
Missing Number |
Solution |
Easy |
|
273 |
Integer to English Words |
Solution |
Hard |
|
278 |
First Bad Version |
Solution |
Easy |
|
283 |
Move Zeroes |
Solution |
Easy |
|
290 |
Word Pattern |
Solution |
Easy |
|
292 |
Nim Game |
Solution |
Easy |
|
295 |
Find Median from Data Stream |
Solution |
Hard |
|
300 |
Longest Increasing Subsequence |
Solution |
Medium |
|
303 |
Range Sum Query - Immutable |
Solution |
Easy |
|
309 |
Best Time to Buy and Sell Stock with Cooldown |
Solution |
Medium |
|
326 |
Power of Three |
Solution |
Easy |
|
328 |
Odd Even Linked List |
Solution |
Medium |
|
342 |
Power of Four |
Solution |
Easy |
|
344 |
Reverse String |
Solution |
Easy |
|
347 |
Top K Frequent Elements |
Solution |
Medium |
|
349 |
Intersection of Two Arrays |
Solution |
Easy |
|
350 |
Intersection of Two Arrays II |
Solution |
Easy |
|
354 |
Russian Doll Envelopes |
Solution |
Hard |
|
367 |
Valid Perfect Square |
Solution |
Easy |
|
371 |
Sum of Two Integers |
Solution |
Easy |
|
380 |
Insert Delete GetRandom O(1) |
Solution |
Medium |
|
381 |
Insert Delete GetRandom O(1) - Duplicates allowed |
Solution |
Hard |
|
383 |
Ransom Note |
Solution |
Easy |
|
384 |
Shuffle an Array |
Solution |
Medium |
|
387 |
First Unique Character in a String |
Solution |
Easy |
|
389 |
Find the Difference |
Solution |
Easy |
|
412 |
Fizz Buzz |
Solution |
Easy |
|
414 |
Third Maximum Number |
Solution |
Easy |
|
429 |
N-ary Tree Level Order Traversal |
Solution |
Easy |
|
437 |
Path Sum III |
Solution |
Easy |
|
442 |
Find All Duplicates in an Array |
Solution |
Medium |
|
443 |
String Compression |
Solution |
Easy |
|
445 |
Add Two Numbers II |
Solution |
Medium |
|
448 |
Find All Numbers Disappeared in an Array |
Solution |
Easy |
|
454 |
4Sum II |
Solution |
Medium |
|
461 |
Hamming Distance |
Solution |
Easy |
|
470 |
Implement Rand10() Using Rand7() |
Solution |
Medium |
|
477 |
Total Hamming Distance |
Solution |
Medium |
|
480 |
Sliding Window Median |
Solution |
Hard |
|
500 |
Keyboard Row |
Solution |
Easy |
|
509 |
Fibonacci Number |
Solution |
Easy |
|
516 |
Longest Palindromic Subsequence |
Solution |
Medium |
|
518 |
Coin Change 2 |
Solution |
Medium |
|
520 |
Detect Capital |
Solution |
Easy |
|
525 |
Contiguous Array |
Solution |
Medium |
|
543 |
Diameter of Binary Tree |
Solution |
Easy |
|
559 |
Maximum Depth of N-ary Tree |
Solution |
Easy |
|
560 |
Subarray Sum Equals K |
Solution |
Medium |
|
572 |
Subtree of Another Tree |
Solution |
Easy |
|
581 |
Shortest Unsorted Continuous Subarray |
Solution |
Easy |
|
589 |
N-ary Tree Preorder Traversal |
Solution |
Easy |
|
590 |
N-ary Tree Postorder Traversal |
Solution |
Easy |
|
595 |
Big Countries |
Solution |
Easy |
|
596 |
Classes More Than 5 Students |
Solution |
Easy |
|
601 |
Human Traffic of Stadium |
Solution |
Hard |
|
617 |
Merge Two Binary Trees |
Solution |
Easy |
|
620 |
Not Boring Movies |
Solution |
Easy |
|
626 |
Exchange Seats |
Solution |
Medium |
|
627 |
Swap Salary |
Solution |
Easy |
|
692 |
Top K Frequent Words |
Solution |
Medium |
|
695 |
Max Area of Island |
Solution |
Medium |
|
703 |
Kth Largest Element in a Stream |
Solution |
Easy |
|
704 |
Binary Search |
Solution |
Easy |
|
706 |
Design HashMap |
Solution |
Easy |
|
707 |
Design Linked List |
Solution |
Easy |
|
709 |
To Lower Case |
Solution |
Easy |
|
733 |
Flood Fill |
Solution |
Easy |
|
771 |
Jewels and Stones |
Solution |
Easy |
|
895 |
Maximum Frequency Stack |
Solution |
Hard |
|
912 |
Sort an Array |
Solution |
Medium |
|
976 |
Largest Perimeter Triangle |
Solution |
Easy |
|
1010 |
Pairs of Songs With Total Durations Divisible by 60 |
Solution |
Easy |
|
1092 |
Shortest Common Supersequence |
Solution |
Hard |
|
1114 |
Print in Order |
Solution |
Easy |
|
1115 |
Print FooBar Alternately |
Solution |
Medium |
|
1116 |
Print Zero Even Odd |
Solution |
Medium |
|
1117 |
Building H2O |
Solution |
Medium |
|
1139 |
Largest 1-Bordered Square |
Solution |
Medium |
|
1179 |
Reformat Department Table |
Solution |
Easy |
|
1195 |
Fizz Buzz Multithreaded |
Solution |
Medium |
|
1207 |
Unique Number of Occurrences |
Solution |
Easy |
|