✅ |
1 |
Two Sum |
Easy |
|
|
✅ |
2 |
Add Two Numbers |
Medium |
|
|
✅ |
3 |
Longest Substring Without Repeating Characters |
Medium |
|
|
✅ |
4 |
Median of Two Sorted Arrays |
Hard |
|
hot |
✅ |
5 |
Longest Palindromic Substring |
Medium |
|
|
✅ |
7 |
Reverse Integer |
Medium |
|
|
⬜ |
8 |
String to Integer (atoi) |
Medium |
|
|
✅ |
10 |
Regular Expression Matching |
Hard |
|
hot |
✅ |
11 |
Container With Most Water |
Medium |
|
|
✅ |
12 |
Integer to Roman |
Medium |
|
|
✅ |
13 |
Roman to Integer |
Easy |
|
|
✅ |
14 |
Longest Common Prefix |
Easy |
|
|
✅ |
15 |
3Sum |
Medium |
|
|
✅ |
16 |
3Sum Closest |
Medium |
|
|
✅ |
17 |
Letter Combinations of a Phone Number |
Medium |
|
|
✅ |
19 |
Remove Nth Node From End of List |
Easy |
|
|
✅ |
20 |
Valid Parentheses |
Easy |
|
|
✅ |
21 |
Merge Two Sorted Lists |
Easy |
|
|
✅ |
22 |
Generate Parentheses |
Medium |
|
|
✅ |
23 |
Merge k Sorted Lists |
Hard |
|
hot |
✅ |
24 |
Swap Nodes in Pairs |
Medium |
|
|
✅ |
25 |
Reverse Nodes in k-Group |
Hard |
|
hot |
✅ |
26 |
Remove Duplicates from Sorted Array |
Easy |
|
|
⬜ |
28 |
Implement strStr() |
Medium |
|
|
⬜ |
29 |
Divide Two Integers |
Medium |
|
|
✅ |
30 |
Substring with Concatenation of All Words |
Hard |
|
hot |
✅ |
31 |
Next Permutation |
Medium |
|
|
✅ |
32 |
Longest Valid Parentheses |
Hard |
|
hot |
✅ |
33 |
Search in Rotated Sorted Array |
Medium |
|
|
✅ |
34 |
Search for a Range |
Medium |
|
|
✅ |
35 |
Search Insert Position |
Medium |
|
|
✅ |
36 |
isValidSudoku |
Medium |
|
|
✅ |
37 |
Sudoku Solver |
Hard |
|
hot |
✅ |
39 |
Combination Sum |
Medium |
|
|
✅ |
40 |
Combination Sum II |
Medium |
|
|
✅ |
41 |
First Missing Positive |
Hard |
|
hot |
✅ |
42 |
Trapping Rain Water |
Hard |
|
hot |
✅ |
43 |
Multiply Strings |
Medium |
|
|
✅ |
44 |
Wildcard Matching |
Hard |
|
hot |
✅ |
45 |
Jump Game II |
Medium |
|
|
✅ |
46 |
Permutations |
Medium |
|
|
✅ |
47 |
Permutations II |
Medium |
|
|
✅ |
48 |
Rotate Image |
Medium |
|
|
⬜ |
50 |
Pow(x, n) |
Medium |
|
|
✅ |
51 |
N-Queens |
Hard |
|
hot |
✅ |
52 |
N-Queens II |
Hard |
|
hot |
✅ |
53 |
Maximum Subarray |
Medium |
|
|
✅ |
54 |
Spiral Matrix |
Medium |
|
|
✅ |
55 |
Jump Game |
Medium |
|
|
✅ |
56 |
Merge Intervals |
Medium |
|
|
✅ |
60 |
Permutation Sequence |
Hard |
|
hot |
✅ |
62 |
Unique Paths |
Medium |
|
|
✅ |
63 |
Unique Paths II |
Medium |
|
|
✅ |
64 |
Minimum Path Sum |
Medium |
|
|
✅ |
65 |
Valid Number |
Hard |
|
hot |
✅ |
66 |
Plus One |
Easy |
|
|
✅ |
68 |
Text Justification |
Hard |
|
hot |
⬜ |
69 |
Sqrt(x) |
Medium |
|
|
✅ |
70 |
Climbing Stairs |
Easy |
|
|
✅ |
72 |
Edit Distance |
Hard |
|
hot |
✅ |
74 |
Search a 2D Matrix |
Medium |
|
|
✅ |
76 |
Minimum Window Substring |
Hard |
|
hot |
✅ |
77 |
Combinations |
Medium |
|
|
✅ |
78 |
Subsets |
Medium |
|
|
✅ |
79 |
Word Search |
Medium |
|
|
✅ |
81 |
Search in Rotated Sorted Array II |
Medium |
|
|
✅ |
82 |
Remove Duplicates from Sorted List II |
Medium |
|
|
✅ |
83 |
Remove Duplicates from Sorted List |
Easy |
|
|
✅ |
84 |
Largest Rectangle in Histogram |
Hard |
|
hot |
✅ |
85 |
Maximal Rectangle |
Hard |
|
hot |
✅ |
86 |
Partition List |
Medium |
|
|
✅ |
87 |
Scramble String |
Hard |
|
hot |
✅ |
88 |
Merge Sorted Array |
Easy |
|
|
✅ |
90 |
Subsets II |
Medium |
|
|
✅ |
91 |
Decode Ways |
Medium |
|
|
✅ |
92 |
Reverse Linked List II |
Medium |
|
|
✅ |
93 |
Restore IP Addresses |
Medium |
|
|
✅ |
94 |
Binary Tree Inorder Traversal |
Medium |
|
|
✅ |
95 |
Unique Binary Search Trees II |
Medium |
|
|
✅ |
97 |
Interleaving String |
Medium |
|
|
✅ |
98 |
Validate Binary Search Tree |
Medium |
|
|
✅ |
99 |
Recover Binary Search Tree |
Medium |
|
|
✅ |
100 |
Same Tree |
Easy |
|
|
✅ |
101 |
Symmetric Tree |
Medium |
|
|
✅ |
102 |
Binary Tree Level Order Traversal |
Easy |
|
|
✅ |
103 |
Binary Tree Zigzag Level Order Traversal |
Medium |
|
|
✅ |
104 |
Maximum Depth of Binary Tree |
Easy |
|
|
✅ |
105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Medium |
|
|
✅ |
106 |
Construct Binary Tree from Inorder and Postorder Traversal |
Medium |
|
|
✅ |
107 |
Binary Tree Level Order Traversal II |
Easy |
|
|
✅ |
108 |
Convert Sorted Array to Binary Search Tree |
Medium |
|
|
✅ |
109 |
Convert Sorted List to Binary Search Tree |
Medium |
|
|
✅ |
110 |
Balanced Binary Tree |
Easy |
|
|
✅ |
111 |
Minimum Depth of Binary Tree |
Medium |
|
|
✅ |
112 |
Path Sum |
Easy |
|
|
✅ |
113 |
Path Sum II |
Medium |
|
|
✅ |
114 |
Flatten Binary Tree to Linked List |
Medium |
|
|
✅ |
115 |
Distinct Subsequences |
Hard |
|
hot |
✅ |
116 |
Populating Next Right Pointers in Each Node |
Medium |
|
|
✅ |
117 |
Populating Next Right Pointers in Each Node II |
Hard |
|
|
✅ |
118 |
Pascal's Triangle |
Medium |
|
|
✅ |
120 |
Triangle |
Medium |
|
|
✅ |
121 |
Best Time to Buy and Sell Stock |
Medium |
|
|
✅ |
122 |
Best Time to Buy and Sell Stock II |
Medium |
|
|
✅ |
123 |
Best Time to Buy and Sell Stock III |
Hard |
|
|
✅ |
124 |
Binary Tree Maximum Path Sum |
Hard |
|
hot |
✅ |
128 |
Longest Consecutive Sequence |
Medium |
|
|
✅ |
129 |
Sum Root to Leaf Numbers |
Medium |
|
|
✅ |
130 |
Surrounded Regions |
Medium |
|
|
✅ |
131 |
Palindrome Partitioning |
Medium |
|
|
✅ |
132 |
Palindrome Partitioning II |
Hard |
|
|
✅ |
133 |
Clone Graph |
Medium |
|
|
✅ |
135 |
Candy |
Hard |
|
hot |
✅ |
136 |
Single Number |
Medium |
|
|
✅ |
137 |
Single Number II |
Medium |
|
|
✅ |
138 |
Copy List with Random Pointer |
Hard |
|
|
✅ |
139 |
Word Break |
Medium |
|
|
✅ |
141 |
Linked List Cycle |
Medium |
|
|
✅ |
142 |
Linked List Cycle II |
Medium |
|
|
✅ |
143 |
Reorder List |
Medium |
|
|
✅ |
144 |
Binary Tree Preorder Traversal |
Easy |
|
|
✅ |
145 |
Binary Tree Postorder Traversal |
Easy |
|
|
✅ |
146 |
LRU Cache |
Medium |
|
hot |
✅ |
147 |
Insertion Sort List |
Medium |
|
|
✅ |
148 |
Sort List |
Medium |
|
|
✅ |
150 |
Evaluate Reverse Polish Notation |
Medium |
|
|
✅ |
152 |
Maximum Product Subarray |
Medium |
|
|
✅ |
153 |
Find Minimum in Rotated Sorted Array |
Medium |
|
|
✅ |
154 |
Find Minimum in Rotated Sorted Array II |
Hard |
|
|
✅ |
155 |
Min Stack |
Easy |
|
|
✅ |
160 |
Intersection of Two Linked Lists |
Easy |
|
|
⬜ |
162 |
Find Peak Element |
Medium |
|
|
✅ |
164 |
Maximum Gap |
Hard |
|
|
✅ |
169 |
Majority Element |
Easy |
|
|
✅ |
173 |
Binary Search Tree Iterator |
Medium |
|
|
✅ |
174 |
Dungeon Game |
Hard |
|
|
⬜ |
179 |
Largest Number |
Medium |
|
|
✅ |
188 |
Best Time to Buy and Sell Stock IV |
Hard |
|
hot |
✅ |
189 |
Rotate Array |
Medium |
|
|
✅ |
190 |
Reverse Bits |
Easy |
|
|
✅ |
191 |
Number of 1 Bits |
Easy |
|
|
✅ |
198 |
House Robber |
Easy |
|
|
✅ |
199 |
Binary Tree Right Side View |
Medium |
|
|
✅ |
200 |
Number of Islands |
Medium |
|
|
✅ |
206 |
Reverse Linked List |
Easy |
|
|
✅ |
208 |
Implement Trie (Prefix Tree) |
Medium |
|
|
✅ |
209 |
Minimum Size Subarray Sum |
Medium |
|
|
✅ |
211 |
Add and Search Word - Data structure design |
Medium |
|
|
✅ |
212 |
Word Search II |
Hard |
|
|
✅ |
213 |
House Robber II |
Medium |
|
|
⬜ |
214 |
Shortest Palindrome |
Hard |
|
|
✅ |
215 |
Kth Largest Element in an Array |
Medium |
|
|
✅ |
216 |
Combination Sum III |
Medium |
|
|
✅ |
217 |
Contains Duplicate |
Easy |
|
|
✅ |
218 |
The Skyline Problem |
Hard |
|
|
✅ |
221 |
Maximal Square |
Medium |
|
|
✅ |
222 |
Count Complete Tree Nodes |
Medium |
|
|
✅ |
224 |
Basic Calculator |
Medium |
|
hot |
✅ |
225 |
Implement Stack using Queues |
Medium |
|
|
✅ |
226 |
Invert Binary Tree |
Easy |
|
|
✅ |
232 |
Implement Queue using Stacks |
Easy |
|
|
⬜ |
233 |
Number of Digit One |
Hard |
|
|
✅ |
234 |
Palindrome Linked List |
Easy |
|
|
✅ |
235 |
Lowest Common Ancestor of a Binary Search Tree |
Medium |
|
|
✅ |
236 |
Lowest Common Ancestor of a Binary Tree |
Medium |
|
|
✅ |
237 |
Delete Node in a Linked List |
Easy |
|
|
✅ |
239 |
Sliding Window Maximum |
Hard |
|
|
✅ |
256 |
Paint House $ |
Medium |
|
|
✅ |
257 |
Binary Tree Paths |
Easy |
|
|
✅ |
260 |
Single Number III |
Medium |
|
|
✅ |
264 |
Ugly Number II |
Medium |
|
|
✅ |
265 |
Paint House II $ |
Hard |
|
|
✅ |
268 |
Missing Number |
Easy |
|
|
✅ |
278 |
First Bad Version |
Easy |
|
|
✅ |
279 |
Perfect Squares |
Medium |
|
|
✅ |
283 |
Move Zeroes |
Easy |
|
|
✅ |
285 |
Inorder Successor in BST $ |
Medium |
|
|
✅ |
295 |
Find Median from Data Stream |
Hard |
|
hot |
✅ |
297 |
Serialize and Deserialize Binary Tree |
Medium |
|
|
✅ |
300 |
Longest Increasing Subsequence |
Medium |
|
|
✅ |
303 |
Range Sum Query - Immutable |
Easy |
|
|
✅ |
304 |
Range Sum Query 2D - Immutable |
Medium |
|
|
✅ |
309 |
Best Time to Buy and Sell Stock with Cooldown |
Medium |
|
|
⬜ |
312 |
Burst Balloons |
Hard |
|
|
✅ |
316 |
Remove Duplicate Letters |
Medium |
|
|
✅ |
322 |
Coin Change |
Medium |
|
|
✅ |
329 |
Longest Increasing Path in a Matrix |
Medium |
|
hot |
✅ |
337 |
House Robber III |
Medium |
|
|
✅ |
338 |
Counting Bits |
Medium |
|
|
✅ |
340 |
Longest Substring with At Most K Distinct Characters $ |
Hard |
|
|
✅ |
343 |
Integer Break |
Medium |
|
|
✅ |
344 |
Reverse String |
Easy |
|
|
✅ |
347 |
Top K Frequent Elements |
Medium |
|
|
✅ |
349 |
Intersection of Two Arrays |
Easy |
|
|
✅ |
354 |
Russian Doll Envelopes |
Hard |
|
|
✅ |
363 |
Max Sum of Rectangle No Larger Than K |
Hard |
|
|
✅ |
368 |
Largest Divisible Subset |
Medium |
|
|
✅ |
370 |
Range Addition $ |
Medium |
|
|
✅ |
377 |
Combination Sum IV |
Medium |
|
|
✅ |
394 |
Decode String |
Medium |
|
|
✅ |
401 |
Binary Watch |
Easy |
|
|
✅ |
402 |
Remove K Digits |
Medium |
|
|
✅ |
403 |
Frog Jump |
Hard |
|
|
✅ |
404 |
Sum of Left Leaves |
Easy |
|
|
⬜ |
407 |
Trapping Rain Water II |
Hard |
|
|
✅ |
410 |
Split Array Largest Sum |
Hard |
|
hot |
✅ |
413 |
Arithmetic Slices |
Medium |
|
|
✅ |
416 |
Partition Equal Subset Sum |
Medium |
|
|
✅ |
426 |
Convert Binary Search Tree to Sorted Doubly Linked List |
Medium |
|
|
✅ |
437 |
Path Sum III |
Easy |
|
|
✅ |
438 |
Find All Anagrams in a String |
Easy |
|
|
✅ |
440 |
K-th Smallest in Lexicographical Order |
Hard |
|
hot |
✅ |
448 |
Find All Numbers Disappeared in an Array |
Easy |
|
|
✅ |
449 |
Serialize and Deserialize BST |
Medium |
|
|
✅ |
450 |
Delete Node in a BST |
Medium |
|
|
✅ |
451 |
Sort Characters By Frequency |
Medium |
|
|
⬜ |
459 |
Repeated Substring Pattern |
Easy |
|
|
✅ |
460 |
LFU Cache |
Hard |
|
hot |
✅ |
461 |
Hamming Distance |
Easy |
|
|
✅ |
474 |
Ones and Zeroes |
Medium |
|
|
✅ |
475 |
Heaters |
Medium |
|
|
⬜ |
488 |
Zuma Game |
Hard |
|
|
✅ |
494 |
Target Sum |
Medium |
|
|
✅ |
496 |
Next Greater Element I |
Easy |
|
|
✅ |
501 |
Find Mode in Binary Search Tree |
Easy |
|
|
✅ |
503 |
Next Greater Element II |
Medium |
|
|
✅ |
509 |
Fibonacci Number |
Easy |
|
|
✅ |
510 |
Inorder Successor in BST II $ |
Medium |
|
|
✅ |
518 |
Coin Change 2 |
Medium |
|
|
✅ |
529 |
Minesweeper |
Medium |
|
|
✅ |
538 |
Convert BST to Greater Tree |
Medium |
|
|
✅ |
542 |
01 Matrix |
Medium |
|
|
✅ |
543 |
Diameter of Binary Tree |
Easy |
|
|
✅ |
545 |
Boundary of Binary Tree |
Medium |
|
|
✅ |
560 |
Subarray Sum Equals K |
Medium |
|
|
✅ |
567 |
Permutation in String |
Medium |
|
|
✅ |
572 |
Subtree of Another Tree |
Easy |
|
|
✅ |
581 |
Shortest Unsorted Continuous Subarray |
Medium |
|
|
✅ |
583 |
Delete Operation for Two Strings |
Medium |
|
|
✅ |
617 |
Merge Two Binary Trees |
Easy |
|
|
✅ |
622 |
Design Circular Queue |
Medium |
|
|
✅ |
641 |
Design Circular Deque |
Medium |
|
|
⬜ |
647 |
24 Game |
Hard |
|
|
✅ |
650 |
2 Keys Keyboard |
Medium |
|
|
✅ |
652 |
Find Duplicate Subtrees |
Medium |
|
|
✅ |
671 |
Second Minimum Node In a Binary Tree |
Easy |
|
|
✅ |
673 |
Number of Longest Increasing Subsequence |
Medium |
|
|
✅ |
701 |
Insert into a Binary Search Tree |
Medium |
|
|
✅ |
703 |
Kth Largest Element in a Stream |
Easy |
|
|
✅ |
704 |
Binary Search |
Easy |
|
|
✅ |
705 |
Design HashSet |
Easy |
|
|
✅ |
706 |
Design HashMap |
Easy |
|
|
✅ |
707 |
Design Linked List |
Easy |
|
|
✅ |
712 |
Minimum ASCII Delete Sum for Two Strings |
Medium |
|
|
✅ |
714 |
Best Time to Buy and Sell Stock with Transaction Fee |
Medium |
|
|
✅ |
716 |
Max Stack $ |
Hard |
|
|
✅ |
718 |
Maximum Length of Repeated Subarray |
Medium |
|
|
✅ |
733 |
Flood Fill |
Easy |
|
|
✅ |
739 |
Daily Temperatures |
Medium |
|
|
✅ |
740 |
Delete and Earn |
Medium |
|
|
✅ |
784 |
Letter Case Permutation |
Easy |
|
|
✅ |
801 |
Minimum Swaps To Make Sequences Increasing |
Medium |
|
|
✅ |
813 |
Largest Sum of Averages |
Medium |
|
|
✅ |
862 |
Shortest Subarray with Sum at Least K |
Hard |
|
|
✅ |
863 |
All Nodes Distance K in Binary Tree |
Medium |
|
|
✅ |
871 |
Minimum Number of Refueling Stops |
Hard |
|
|
✅ |
873 |
Length of Longest Fibonacci Subsequence |
Medium |
|
|
✅ |
879 |
Profitable Schemes |
Hard |
|
|
✅ |
889 |
Construct Binary Tree from Preorder and Postorder Traversal |
Medium |
|
|
✅ |
912 |
Sort an Array |
Medium |
|
|
✅ |
918 |
Maximum Sum Circular Subarray |
Medium |
|
|
✅ |
931 |
Minimum Falling Path Sum |
Medium |
|
|
✅ |
1008 |
Construct Binary Search Tree from Preorder Traversal |
Medium |
|
|
✅ |
1013 |
Partition Array Into Three Parts With Equal Sum |
Easy |
|
|
✅ |
1027 |
Longest Arithmetic Subsequence |
Medium |
|
|
✅ |
1028 |
Recover a Tree From Preorder Traversal |
Hard |
|
|
✅ |
1038 |
Binary Search Tree to Greater Sum Tree |
Medium |
|
|
⬜ |
1044 |
Longest Duplicate Substring |
Hard |
|
|
✅ |
1049 |
Last Stone Weight II |
Medium |
|
|
✅ |
1055 |
Shortest Way to Form String $ |
Medium |
|
|
✅ |
1081 |
Smallest Subsequence of Distinct Characters |
Medium |
|
|
✅ |
1108 |
Defanging an IP Address |
Easy |
|
|
✅ |
1143 |
Longest Common Subsequence |
Medium |
|
|
✅ |
1155 |
Number of Dice Rolls With Target Sum |
Medium |
|
|
✅ |
1206 |
Design Skiplist |
Hard |
|
|
✅ |
1277 |
Count Square Submatrices with All Ones |
Medium |
|
|
✅ |
1372 |
Longest ZigZag Path in a Binary Tree |
Medium |
|
|
✅ |
1388 |
Pizza With 3n Slices |
Hard |
|
|
✅ |
1473 |
Paint House III |
Hard |
|
|
✅ |
1670 |
Design Front Middle Back Queue |
Medium |
|
|
✅ |
1804 |
Implement Trie II (Prefix Tree) |
Medium |
|
|
✅ |
1863 |
Sum of All Subset XOR Totals |
Easy |
|
|