| 1 |
Two Sum |
  |
Easy |
| 3 |
Longest Substring Without Repeating Characters |
 |
Medium |
| 5 |
Longest Palindromic Substring |
 |
Medium |
| 8 |
String to Integer (atoi) |
 |
Medium |
| 11 |
Container With Most Water |
 |
Medium |
| 15 |
3Sum |
 |
Medium |
| 17 |
Letter Combinations of a Phone Number |
 |
Medium |
| 19 |
Remove Nth Node From End of List |
 |
Medium |
| 20 |
Valid Parentheses |
 |
Easy |
| 21 |
Merge Two Sorted Lists |
 |
Easy |
| 22 |
Generate Parentheses |
 |
Medium |
| 23 |
Merge k Sorted Lists |
 |
Hard |
| 24 |
Swap Nodes in Pairs |
 |
Medium |
| 28 |
Implement strStr() |
 |
Easy |
| 31 |
Next Permutation |
 |
Medium |
| 32 |
Longest Valid Parentheses |
 |
Hard |
| 33 |
Search in Rotated Sorted Array |
 |
Medium |
| 34 |
Find First and Last Position of Element in Sorted Array |
 |
Medium |
| 36 |
Valid Sudoku |
 |
Medium |
| 38 |
Count and Say |
 |
Medium |
| 39 |
Combination Sum |
 |
Medium |
| 41 |
First Missing Positive |
 |
Hard |
| 42 |
Trapping Rain Water |
 |
Hard |
| 45 |
Jump Game II |
 |
Medium |
| 49 |
Group Anagrams |
 |
Medium |
| 54 |
Spiral Matrix |
 |
Medium |
| 55 |
Jump Game |
 |
Medium |
| 56 |
Merge Intervals |
  |
Medium |
| 61 |
Rotate List |
 |
Medium |
| 62 |
Unique Paths |
 |
Medium |
| 67 |
Add Binary |
 |
Easy |
| 68 |
Text Justification |
 |
Hard |
| 71 |
Simplify Path |
 |
Medium |
| 75 |
Sort Colors |
 |
Medium |
| 80 |
Remove Duplicates from Sorted Array II |
 |
Medium |
| 93 |
Restore IP Addresses |
 |
Medium |
| 94 |
Binary Tree Inorder Traversal |
 |
Easy |
| 98 |
Validate Binary Search Tree |
 |
Medium |
| 102 |
Binary Tree Level Order Traversal |
 |
Medium |
| 107 |
Binary Tree Level Order Traversal II |
 |
Medium |
| 121 |
Best Time to Buy and Sell Stock |
 |
Easy |
| 122 |
Best Time to Buy and Sell Stock II |
 |
Medium |
| 127 |
Word Ladder |
 |
Hard |
| 128 |
Longest Consecutive Sequence |
 |
Medium |
| 131 |
Palindrome Partitioning |
 |
Medium |
| 136 |
Single Number |
 |
Easy |
| 141 |
Linked List Cycle |
 |
Easy |
| 142 |
Linked List Cycle II |
 |
Medium |
| 144 |
Binary Tree Preorder Traversal |
 |
Easy |
| 145 |
Binary Tree Postorder Traversal |
 |
Easy |
| 150 |
Evaluate Reverse Polish Notation |
 |
Medium |
| 159 |
Longest Substring with At Most Two Distinct Characters |
 |
Medium |
| 160 |
Intersection of Two Linked Lists |
 |
Easy |
| 169 |
Majority Element |
 |
Easy |
| 171 |
Excel Sheet Column Number |
 |
Easy |
| 173 |
Binary Search Tree Iterator |
 |
Medium |
| 198 |
House Robber |
 |
Medium |
| 200 |
Number of Islands |
  |
Medium |
| 206 |
Reverse Linked List |
 |
Easy |
| 209 |
Minimum Size Subarray Sum |
 |
Medium |
| 211 |
Design Add and Search Words Data Structure |
 |
Medium |
| 213 |
House Robber II |
 |
Medium |
| 223 |
Rectangle Area |
 |
Medium |
| 224 |
Basic Calculator |
 |
Hard |
| 233 |
Number of Digit One |
 |
Hard |
| 236 |
Lowest Common Ancestor of a Binary Tree |
 |
Medium |
| 238 |
Product of Array Except Self |
 |
Medium |
| 247 |
Strobogrammatic Number II |
 |
Medium |
| 249 |
Group Shifted Strings |
 |
Medium |
| 252 |
Meeting Rooms |
 |
Easy |
| 253 |
Meeting Rooms II |
  |
Medium |
| 259 |
3Sum Smaller |
 |
Medium |
| 263 |
Ugly Number |
  |
Easy |
| 286 |
Walls and Gates |
  |
Medium |
| 290 |
Word Pattern |
 |
Easy |
| 301 |
Remove Invalid Parentheses |
 |
Hard |
| 311 |
Sparse Matrix Multiplication |
 |
Medium |
| 314 |
Binary Tree Vertical Order Traversal |
 |
Medium |
| 322 |
Coin Change |
 |
Medium |
| 326 |
Power of Three |
 |
Easy |
| 329 |
Longest Increasing Path in a Matrix |
 |
Hard |
| 338 |
Counting Bits |
 |
Easy |
| 340 |
Longest Substring with At Most K Distinct Characters |
 |
Medium |
| 347 |
Top K Frequent Elements |
 |
Medium |
| 366 |
Find Leaves of Binary Tree |
 |
Medium |
| 387 |
First Unique Character in a String |
 |
Easy |
| 424 |
Longest Repeating Character Replacement |
 |
Medium |
| 429 |
N-ary Tree Level Order Traversal |
 |
Medium |
| 436 |
Find Right Interval |
 |
Medium |
| 438 |
Find All Anagrams in a String |
 |
Medium |
| 445 |
Add Two Numbers II |
 |
Medium |
| 449 |
Serialize and Deserialize BST |
 |
Medium |
| 452 |
Minimum Number of Arrows to Burst Balloons |
 |
Medium |
| 520 |
Detect Capital |
 |
Easy |
| 529 |
Minesweeper |
 |
Medium |
| 560 |
Subarray Sum Equals K |
 |
Medium |
| 567 |
Permutation in String |
 |
Medium |
| 605 |
Can Place Flowers |
 |
Easy |
| 621 |
Task Scheduler |
 |
Medium |
| 647 |
Palindromic Substrings |
 |
Medium |
| 657 |
Robot Return to Origin |
 |
Easy |
| 660 |
Remove 9 |
 |
Hard |
| 692 |
Top K Frequent Words |
 |
Medium |
| 694 |
Number of Distinct Islands |
 |
Medium |
| 695 |
Max Area of Island |
 |
Medium |
| 701 |
Insert into a Binary Search Tree |
   |
Medium |
| 706 |
Design HashMap |
 |
Easy |
| 728 |
Self Dividing Numbers |
 |
Easy |
| 735 |
Asteroid Collision |
 |
Medium |
| 739 |
Daily Temperatures |
 |
Medium |
| 763 |
Partition Labels |
 |
Medium |
| 849 |
Maximize Distance to Closest Person |
 |
Medium |
| 856 |
Score of Parentheses |
 |
Medium |
| 862 |
Shortest Subarray with Sum at Least K |
 |
Hard |
| 875 |
Koko Eating Bananas |
 |
Medium |
| 877 |
Stone Game |
 |
Medium |
| 881 |
Boats to Save People |
 |
Medium |
| 895 |
Maximum Frequency Stack |
 |
Hard |
| 921 |
Minimum Add to Make Parentheses Valid |
 |
Medium |
| 946 |
Validate Stack Sequences |
  |
Medium |
| 987 |
Vertical Order Traversal of a Binary Tree |
 |
Hard |
| 992 |
Subarrays with K Different Integers |
 |
Hard |
| 997 |
Find the Town Judge |
  |
Easy |
| 1004 |
Max Consecutive Ones III |
 |
Medium |
| 1007 |
Minimum Domino Rotations For Equal Row |
 |
Medium |
| 1011 |
Capacity To Ship Packages Within D Days |
 |
Medium |
| 1015 |
Smallest Integer Divisible by K |
 |
Medium |
| 1022 |
Sum of Root To Leaf Binary Numbers |
  |
Easy |
| 1026 |
Maximum Difference Between Node and Ancestor |
   |
Medium |
| 1029 |
Two City Scheduling |
 |
Medium |
| 1041 |
Robot Bounded In Circle |
 |
Medium |
| 1044 |
Longest Duplicate Substring |
 |
Hard |
| 1091 |
Shortest Path in Binary Matrix |
 |
Medium |
| 1094 |
Car Pooling |
 |
Medium |
| 1100 |
Find K-Length Substrings With No Repeated Characters |
 |
Medium |
| 1143 |
Longest Common Subsequence |
 |
Medium |
| 1244 |
Design A Leaderboard |
 |
Medium |
| 1249 |
Minimum Remove to Make Valid Parentheses |
 |
Medium |
| 1288 |
Remove Covered Intervals |
 |
Medium |
| 1291 |
Sequential Digits |
 |
Medium |
| 1448 |
Count Good Nodes in Binary Tree |
 |
Medium |
| 1472 |
Design Browser History |
 |
Medium |
| 1602 |
Find Nearest Right Node in Binary Tree |
 |
Medium |
| 1695 |
Maximum Erasure Value |
 |
Medium |
| 1721 |
Swapping Nodes in a Linked List |
 |
Medium |
| 1763 |
Longest Nice Substring |
 |
Easy |
| 1838 |
Frequency of the Most Frequent Element |
 |
Medium |
| 1884 |
Egg Drop With 2 Eggs and N Floors |
 |
Medium |
| 1887 |
Reduction Operations to Make the Array Elements Equal |
 |
Medium |
| 2024 |
Maximize the Confusion of an Exam |
 |
Medium |