| 1 | Two Sum | Easy | 
| 2 | Add Two Numbers | Medium | 
| 3 | Longest Substring Without Repeating Characters | Medium | 
| 4 | Median of Two Sorted Arrays | Hard | 
| 5 | Longest Palindromic Substring | Medium | 
| 6 | ZigZag Conversion | Medium | 
| 7 | Reverse Integer | Easy | 
| 8 | String to Integer (atoi) | Medium | 
| 9 | Palindrome Number | Easy | 
| 10 | Regular Expression Matching | Hard | 
| 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 | 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 | 
| 25 | Reverse Nodes in k-Group | Hard | 
| 26 | Remove Duplicates from Sorted Array | Easy | 
| 27 | Remove Element | Easy | 
| 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 | 
| 35 | Search Insert Position | Easy | 
| 36 | Valid Sudoku | Medium | 
| 37 | Sudoku Solver | Hard | 
| 38 | Count and Say | Easy | 
| 39 | Combination Sum | Medium | 
| 40 | Combination Sum II | Medium | 
| 41 | First Missing Positive | Hard | 
| 42 | Trapping Rain Water | Hard | 
| 43 | Multiply Strings | Medium | 
| 45 | Jump Game II | Hard | 
| 46 | Permutations | Medium | 
| 47 | Permutations II | Medium | 
| 48 | Rotate Image | Medium | 
| 49 | Group Anagrams | Medium | 
| 50 | Pow(x, n) | Medium | 
| 51 | N-Queens | Hard | 
| 52 | N-Queens II | Hard | 
| 53 | Maximum Subarray | Easy | 
| 54 | Spiral Matrix | Medium | 
| 55 | Jump Game | Medium | 
| 56 | Merge Intervals | Medium | 
| 57 | Insert Interval | Hard | 
| 58 | Length of Last Word | Easy | 
| 59 | Spiral Matrix II | Medium | 
| 60 | Permutation Sequence | Medium | 
| 61 | Rotate List | Medium | 
| 62 | Unique Paths | Medium | 
| 63 | Unique Paths II | Medium | 
| 64 | Minimum Path Sum | Medium | 
| 66 | Plus One | Easy | 
| 67 | Add Binary | Easy | 
| 68 | Text Justification | Hard | 
| 69 | Sqrt(x) | Easy | 
| 70 | Climbing Stairs | Easy | 
| 71 | Simplify Path | Medium | 
| 73 | Set Matrix Zeroes | Medium | 
| 75 | Sort Colors | Medium | 
| 77 | Combinations | Medium | 
| 78 | Subsets | Medium | 
| 79 | Word Search | Medium | 
| 82 | Remove Duplicates from Sorted List II | Medium | 
| 83 | Remove Duplicates from Sorted List | Easy | 
| 86 | Partition List | Medium | 
| 88 | Merge Sorted Array | Easy | 
| 89 | Gray Code | Medium | 
| 90 | Subsets II | Medium | 
| 92 | Reverse Linked List II | Medium | 
| 94 | Binary Tree Inorder Traversal | Medium | 
| 96 | Unique Binary Search Trees | Medium | 
| 100 | Same Tree | Easy | 
| 101 | Symmetric Tree | Easy | 
| 102 | Binary Tree Level Order Traversal | Medium | 
| 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 | Easy | 
| 109 | Convert Sorted List to Binary Search Tree | Medium | 
| 110 | Balanced Binary Tree | Easy | 
| 111 | Minimum Depth of Binary Tree | Easy | 
| 112 | Path Sum | Easy | 
| 113 | Path Sum II | Medium | 
| 114 | Flatten Binary Tree to Linked List | Medium | 
| 115 | Distinct Subsequences | Hard | 
| 116 | Populating Next Right Pointers in Each Node | Medium | 
| 117 | Populating Next Right Pointers in Each Node II | Medium | 
| 118 | Pascal's Triangle | Easy | 
| 119 | Pascal's Triangle II | Easy | 
| 120 | Triangle | Medium | 
| 121 | Best Time to Buy and Sell Stock | Easy | 
| 122 | Best Time to Buy and Sell Stock II | Easy | 
| 136 | Single Number | Easy | 
| 141 | Linked List Cycle | Easy | 
| 143 | Reorder List | Medium | 
| 147 | Insertion Sort List | Medium | 
| 155 | Min Stack | Easy | 
| 160 | Intersection of Two Linked Lists | Easy | 
| 162 | Find Peak Element | Medium | 
| 167 | Two Sum II - Input array is sorted | Easy | 
| 168 | Excel Sheet Column Title | Easy | 
| 169 | Majority Element | Easy | 
| 171 | Excel Sheet Column Number | Easy | 
| 172 | Factorial Trailing Zeroes | Easy | 
| 189 | Rotate Array | Easy | 
| 190 | Reverse Bits | Easy | 
| 191 | Number of 1 Bits | Easy | 
| 198 | House Robber | Easy | 
| 202 | Happy Number | Easy | 
| 203 | Remove Linked List Elements | Easy | 
| 204 | Count Primes | Easy | 
| 205 | Isomorphic Strings | Easy | 
| 206 | Reverse Linked List | Easy | 
| 217 | Contains Duplicate | Easy | 
| 219 | Contains Duplicate II | Easy | 
| 225 | Implement Stack using Queues | Easy | 
| 226 | Invert Binary Tree | Easy | 
| 230 | Kth Smallest Element in a BST | Medium | 
| 231 | Power of Two | Easy | 
| 232 | Implement Queue using Stacks | Easy | 
| 234 | Palindrome Linked List | Easy | 
| 235 | Lowest Common Ancestor of a Binary Search Tree | Easy | 
| 237 | Delete Node in a Linked List | Easy | 
| 238 | Product of Array Except Self | Medium | 
| 242 | Valid Anagram | Easy | 
| 257 | Binary Tree Paths | Easy | 
| 258 | Add Digits | Easy | 
| 260 | Single Number III | Medium | 
| 263 | Ugly Number | Easy | 
| 268 | Missing Number | Easy | 
| 274 | H-Index | Medium | 
| 278 | First Bad Version | Easy | 
| 283 | Move Zeroes | Easy | 
| 290 | Word Pattern | Easy | 
| 292 | Nim Game | Easy | 
| 299 | Bulls and Cows | Easy | 
| 303 | Range Sum Query - Immutable | Easy | 
| 326 | Power of Three | Easy | 
| 338 | Counting Bits | Medium | 
| 342 | Power of Four | Easy | 
| 344 | Reverse String | Easy | 
| 345 | Reverse Vowels of a String | Easy | 
| 347 | Top K Frequent Elements | Medium | 
| 349 | Intersection of Two Arrays | Easy | 
| 350 | Intersection of Two Arrays II | Easy | 
| 367 | Valid Perfect Square | Easy | 
| 371 | Sum of Two Integers | Easy | 
| 374 | Guess Number Higher or Lower | Easy | 
| 383 | Ransom Note | Easy | 
| 387 | First Unique Character in a String | Easy | 
| 389 | Find the Difference | Easy | 
| 392 | Is Subsequence | Easy | 
| 398 | Random Pick Index | Medium | 
| 400 | Nth Digit | Medium | 
| 401 | Binary Watch | Easy | 
| 404 | Sum of Left Leaves | Easy | 
| 405 | Convert a Number to Hexadecimal | Easy | 
| 406 | Queue Reconstruction by Height | Medium | 
| 409 | Longest Palindrome | Easy | 
| 412 | Fizz Buzz | Easy | 
| 413 | Arithmetic Slices | Medium | 
| 414 | Third Maximum Number | Easy | 
| 415 | Add Strings | Easy | 
| 419 | Battleships in a Board | Medium | 
| 434 | Number of Segments in a String | Easy | 
| 437 | Path Sum III | Easy | 
| 438 | Find All Anagrams in a String | Medium | 
| 441 | Arranging Coins | Easy | 
| 442 | Find All Duplicates in an Array | Medium | 
| 443 | String Compression | Easy | 
| 447 | Number of Boomerangs | Easy | 
| 448 | Find All Numbers Disappeared in an Array | Easy | 
| 451 | Sort Characters By Frequency | Medium | 
| 453 | Minimum Moves to Equal Array Elements | Easy | 
| 455 | Assign Cookies | Easy | 
| 458 | Poor Pigs | Hard | 
| 459 | Repeated Substring Pattern | Easy | 
| 462 | Minimum Moves to Equal Array Elements II | Medium | 
| 463 | Island Perimeter | Easy | 
| 467 | Unique Substrings in Wraparound String | Medium | 
| 475 | Heaters | Easy | 
| 476 | Number Complement | Easy | 
| 479 | Largest Palindrome Product | Hard | 
| 481 | Magical String | Medium | 
| 482 | License Key Formatting | Easy | 
| 485 | Max Consecutive Ones | Easy | 
| 492 | Construct the Rectangle | Easy | 
| 495 | Teemo Attacking | Medium | 
| 496 | Next Greater Element I | Easy | 
| 500 | Keyboard Row | Easy | 
| 501 | Find Mode in Binary Search Tree | Easy | 
| 504 | Base 7 | Easy | 
| 506 | Relative Ranks | Easy | 
| 507 | Perfect Number | Easy | 
| 508 | Most Frequent Subtree Sum | Medium | 
| 513 | Find Bottom Left Tree Value | Medium | 
| 515 | Find Largest Value in Each Tree Row | Medium | 
| 520 | Detect Capital | Easy | 
| 521 | Longest Uncommon Subsequence I | Easy | 
| 526 | Beautiful Arrangement | Medium | 
| 529 | Minesweeper | Medium | 
| 530 | Minimum Absolute Difference in BST | Easy | 
| 532 | K-diff Pairs in an Array | Easy | 
| 535 | Encode and Decode TinyURL | Medium | 
| 537 | Complex Number Multiplication | Medium | 
| 538 | Convert BST to Greater Tree | Easy | 
| 540 | Single Element in a Sorted Array | Medium | 
| 541 | Reverse String II | Easy | 
| 543 | Diameter of Binary Tree | Easy | 
| 547 | Friend Circles | Medium | 
| 551 | Student Attendance Record I | Easy | 
| 553 | Optimal Division | Medium | 
| 557 | Reverse Words in a String III | Easy | 
| 561 | Array Partition I | Easy | 
| 563 | Binary Tree Tilt | Easy | 
| 566 | Reshape the Matrix | Easy | 
| 567 | Permutation in String | Medium | 
| 572 | Subtree of Another Tree | Easy | 
| 575 | Distribute Candies | Easy | 
| 581 | Shortest Unsorted Continuous Subarray | Easy | 
| 594 | Longest Harmonious Subsequence | Easy | 
| 599 | Minimum Index Sum of Two Lists | Easy | 
| 605 | Can Place Flowers | Easy | 
| 606 | Construct String from Binary Tree | Easy | 
| 609 | Find Duplicate File in System | Medium | 
| 617 | Merge Two Binary Trees | Easy | 
| 628 | Maximum Product of Three Numbers | Easy | 
| 633 | Sum of Square Numbers | Easy | 
| 637 | Average of Levels in Binary Tree | Easy | 
| 643 | Maximum Average Subarray I | Easy | 
| 645 | Set Mismatch | Easy | 
| 647 | Palindromic Substrings | Medium | 
| 653 | Two Sum IV - Input is a BST | Easy | 
| 654 | Maximum Binary Tree | Medium | 
| 655 | Print Binary Tree | Medium | 
| 657 | Robot Return to Origin | Easy | 
| 661 | Image Smoother | Easy | 
| 665 | Non-decreasing Array | Easy | 
| 667 | Beautiful Arrangement II | Medium | 
| 669 | Trim a Binary Search Tree | Easy | 
| 671 | Second Minimum Node In a Binary Tree | Easy | 
| 674 | Longest Continuous Increasing Subsequence | Easy | 
| 677 | Map Sum Pairs | Medium | 
| 680 | Valid Palindrome II | Easy | 
| 682 | Baseball Game | Easy | 
| 686 | Repeated String Match | Easy | 
| 687 | Longest Univalue Path | Easy | 
| 690 | Employee Importance | Easy | 
| 693 | Binary Number with Alternating Bits | Easy | 
| 695 | Max Area of Island | Medium | 
| 696 | Count Binary Substrings | Easy | 
| 697 | Degree of an Array | Easy | 
| 713 | Subarray Product Less Than K | Medium | 
| 717 | 1-bit and 2-bit Characters | Easy | 
| 720 | Longest Word in Dictionary | Easy | 
| 724 | Find Pivot Index | Easy | 
| 725 | Split Linked List in Parts | Medium | 
| 728 | Self Dividing Numbers | Easy | 
| 732 | My Calendar III | Hard | 
| 733 | Flood Fill | Easy | 
| 739 | Daily Temperatures | Medium | 
| 709 | To Lower Case | Easy | 
| 744 | Find Smallest Letter Greater Than Target | Easy | 
| 746 | Min Cost Climbing Stairs | Easy | 
| 747 | Largest Number At Least Twice of Others | Easy | 
| 748 | Shortest Completing Word | Easy | 
| 762 | Prime Number of Set Bits in Binary Representation | Easy | 
| 559 | Maximum Depth of N-ary Tree | Easy | 
| 589 | N-ary Tree Preorder Traversal | Easy | 
| 590 | N-ary Tree Postorder Traversal | Easy | 
| 766 | Toeplitz Matrix | Easy | 
| 771 | Jewels and Stones | Easy | 
| 700 | Search in a Binary Search Tree | Easy | 
| 703 | Kth Largest Element in a Stream | Easy | 
| 704 | Binary Search | Easy | 
| 783 | Minimum Distance Between BST Nodes | Easy | 
| 784 | Letter Case Permutation | Easy | 
| 788 | Rotated Digits | Easy | 
| 796 | Rotate String | Easy | 
| 705 | Design HashSet | Easy | 
| 706 | Design HashMap | Easy | 
| 804 | Unique Morse Code Words | Easy | 
| 806 | Number of Lines To Write String | Easy | 
| 811 | Subdomain Visit Count | Easy | 
| 819 | Most Common Word | Easy | 
| 821 | Shortest Distance to a Character | Easy | 
| 824 | Goat Latin | Easy | 
| 830 | Positions of Large Groups | Easy | 
| 832 | Flipping an Image | Easy | 
| 833 | Find And Replace in String | Medium | 
| 836 | Rectangle Overlap | Easy | 
| 840 | Magic Squares In Grid | Easy | 
| 844 | Backspace String Compare | Easy | 
| 849 | Maximize Distance to Closest Person | Easy | 
| 852 | Peak Index in a Mountain Array | Easy | 
| 859 | Buddy Strings | Easy | 
| 860 | Lemonade Change | Easy | 
| 863 | All Nodes Distance K in Binary Tree | Medium | 
| 867 | Transpose Matrix | Easy | 
| 868 | Binary Gap | Easy | 
| 872 | Leaf-Similar Trees | Easy | 
| 874 | Walking Robot Simulation | Easy | 
| 876 | Middle of the Linked List | Easy | 
| 883 | Projection Area of 3D Shapes | Easy | 
| 884 | Uncommon Words from Two Sentences | Easy | 
| 885 | Spiral Matrix III | Medium | 
| 888 | Fair Candy Swap | Easy | 
| 889 | Construct Binary Tree from Preorder and Postorder Traversal | Medium | 
| 890 | Find and Replace Pattern | Medium | 
| 892 | Surface Area of 3D Shapes | Easy | 
| 893 | Groups of Special-Equivalent Strings | Easy | 
| 894 | All Possible Full Binary Trees | Medium | 
| 896 | Monotonic Array | Easy | 
| 897 | Increasing Order Search Tree | Easy | 
| 905 | Sort Array By Parity | Easy | 
| 908 | Smallest Range I | Easy | 
| 912 | Sort an Array | Medium | 
| 914 | X of a Kind in a Deck of Cards | Easy | 
| 921 | Minimum Add to Make Parentheses Valid | Medium | 
| 922 | Sort Array By Parity II | Easy | 
| 925 | Long Pressed Name | Easy | 
| 929 | Unique Email Addresses | Easy | 
| 931 | Minimum Falling Path Sum | Medium | 
| 933 | Number of Recent Calls | Easy | 
| 937 | Reorder Data in Log Files | Easy | 
| 938 | Range Sum of BST | Easy | 
| 941 | Valid Mountain Array | Easy | 
| 942 | DI String Match | Easy | 
| 944 | Delete Columns to Make Sorted | Easy | 
| 946 | Validate Stack Sequences | Medium | 
| 949 | Largest Time for Given Digits | Easy | 
| 950 | Reveal Cards In Increasing Order | Medium | 
| 951 | Flip Equivalent Binary Trees | Medium | 
| 953 | Verifying an Alien Dictionary | Easy | 
| 959 | Regions Cut By Slashes | Medium | 
| 965 | Univalued Binary Tree | Easy | 
| 969 | Pancake Sorting | Medium | 
| 970 | Powerful Integers | Easy | 
| 509 | Fibonacci Number | Easy | 
| 976 | Largest Perimeter Triangle | Easy | 
| 977 | Squares of a Sorted Array | Easy | 
| 979 | Distribute Coins in Binary Tree | Medium | 
| 985 | Sum of Even Numbers After Queries | Easy | 
| 986 | Interval List Intersections | Medium | 
| 989 | Add to Array-Form of Integer | Easy | 
| 993 | Cousins in Binary Tree | Easy | 
| 994 | Rotting Oranges | Medium | 
| 997 | Find the Town Judge | Easy | 
| 998 | Maximum Binary Tree II | Medium | 
| 999 | Available Captures for Rook | Easy | 
| 1002 | Find Common Characters | Easy | 
| 1005 | Maximize Sum Of Array After K Negations | Easy | 
| 1009 | Complement of Base 10 Integer | Easy | 
| 1010 | Pairs of Songs With Total Durations Divisible by 60 | Easy | 
| 1013 | Partition Array Into Three Parts With Equal Sum | Easy | 
| 1018 | Binary Prefix Divisible By 5 | Easy | 
| 1022 | Sum of Root To Leaf Binary Numbers | Easy | 
| 1025 | Divisor Game | Easy | 
| 1030 | Matrix Cells in Distance Order | Easy | 
| 1029 | Two City Scheduling | Easy | 
| 1033 | Moving Stones Until Consecutive | Easy | 
| 1160 | Find Words That Can Be Formed by Characters | Easy | 
| 1037 | Valid Boomerang | Easy | 
| 1042 | Flower Planting With No Adjacent | Easy | 
| 1046 | Last Stone Weight | Easy | 
| 1047 | Remove All Adjacent Duplicates In String | Easy | 
| 1051 | Height Checker | Easy | 
| 1071 | Greatest Common Divisor of Strings | Easy | 
| 1078 | Occurrences After Bigram | Easy | 
| 1089 | Duplicate Zeros | Easy | 
| 1103 | Distribute Candies to People | Easy | 
| 1108 | Defanging an IP Address | Easy | 
| 1122 | Relative Sort Array | Easy | 
| 1287 | Element Appearing More Than 25% In Sorted Array | Easy | 
| 1128 | Number of Equivalent Domino Pairs | Easy | 
| 1299 | Replace Elements with Greatest Element on Right Side | Easy | 
| 1137 | N-th Tribonacci Number | Easy | 
| 1313 | Decompress Run-Length Encoded List | Easy | 
| 1331 | Rank Transform of an Array | Easy | 
| 1154 | Day of the Year | Easy | 
| 1171 | Remove Zero Sum Consecutive Nodes from Linked List | Medium | 
| 1170 | Compare Strings by Frequency of the Smallest Character | Easy | 
| 1360 | Number of Days Between Two Dates | Easy | 
| 1175 | Prime Arrangements | Easy | 
| 1184 | Distance Between Bus Stops | Easy | 
| 1185 | Day of the Week | Easy | 
| 1189 | Maximum Number of Balloons | Easy | 
| 1200 | Minimum Absolute Difference | Easy | 
| 1207 | Unique Number of Occurrences | Easy | 
| 1217 | Play with Chips | Easy | 
| 1221 | Split a String in Balanced Strings | Easy | 
| 1232 | Check If It Is a Straight Line | Easy | 
| 1237 | Find Positive Integer Solution for a Given Equation | Easy | 
| 1252 | Cells with Odd Values in a Matrix | Easy | 
| 1260 | Shift 2D Grid | Easy | 
| 1266 | Minimum Time Visiting All Points | Easy | 
| 1275 | Find Winner on a Tic Tac Toe Game | Easy | 
| 1281 | Subtract the Product and Sum of Digits of an Integer | Easy | 
| 1290 | Convert Binary Number in a Linked List to Integer | Easy | 
| 1295 | Find Numbers with Even Number of Digits | Easy | 
| 1304 | Find N Unique Integers Sum up to Zero | Easy | 
| 1309 | Decrypt String from Alphabet to Integer Mapping | Easy | 
| 1317 | Convert Integer to the Sum of Two No-Zero Integers | Easy | 
| 1342 | Number of Steps to Reduce a Number to Zero | Easy | 
| 1323 | Maximum 69 Number | Easy | 
| 1356 | Sort Integers by The Number of 1 Bits | Easy | 
| 1337 | The K Weakest Rows in a Matrix | Easy | 
| 1346 | Check If N and Its Double Exist | Easy | 
| 1370 | Increasing Decreasing String | Easy | 
| 1351 | Count Negative Numbers in a Sorted Matrix | Easy | 
| 1365 | How Many Numbers Are Smaller Than the Current Number | Easy | 
| 1385 | Find the Distance Value Between Two Arrays | Easy | 
| 1374 | Generate a String With Characters That Have Odd Counts | Easy | 
| 1380 | Lucky Numbers in a Matrix | Easy | 
| 1399 | Count Largest Group | Easy | 
| 1389 | Create Target Array in the Given Order | Easy | 
| 1394 | Find Lucky Integer in an Array | Easy | 
| 1413 | Minimum Value to Get Positive Step by Step Sum | Easy | 
| 1403 | Minimum Subsequence in Non-Increasing Order | Easy | 
| 1408 | String Matching in an Array | Easy | 
| 1431 | Kids With the Greatest Number of Candies | Easy | 
| 1417 | Reformat The String | Easy | 
| 1422 | Maximum Score After Splitting a String | Easy | 
| 1446 | Consecutive Characters | Easy | 
| 1436 | Destination City | Easy | 
| 1441 | Build an Array With Stack Operations | Easy | 
| 1460 | Make Two Arrays Equal by Reversing Sub-arrays | Easy | 
| 1450 | Number of Students Doing Homework at a Given Time | Easy | 
| 1455 | Check If a Word Occurs As a Prefix of Any Word in a Sentence | Easy | 
| 1475 | Final Prices With a Special Discount in a Shop | Easy | 
| 1464 | Maximum Product of Two Elements in an Array | Easy | 
| 1470 | Shuffle the Array | Easy | 
| 1480 | Running Sum of 1d Array | Easy |