leetcode 题目目录 # Title Difficulty 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 18 4Sum 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 29 Divide Two Integers Medium 30 Substring with Concatenation of All Words Hard 31 Next Permutation Medium 32 Longest Valid Parentheses Hard 33 Search in Rotated Sorted Array Medium 34 Search for a Range 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 44 Wildcard Matching Hard 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 65 Valid Number Hard 66 Plus One Easy 67 Add Binary Easy 68 Text Justification Hard 69 Sqrt(x) Easy 70 Climbing Stairs Easy 71 Simplify Path Medium 72 Edit Distance Hard 73 Set Matrix Zeroes Medium 74 Search a 2D Matrix Medium 75 Sort Colors Medium 76 Minimum Window Substring Hard 77 Combinations Medium 78 Subsets Medium 79 Word Search Medium 80 Remove Duplicates from Sorted Array II 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 85 Maximal Rectangle Hard 86 Partition List Medium 87 Scramble String Hard 88 Merge Sorted Array Easy 89 Gray Code Medium 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 96 Unique Binary Search Trees Medium 97 Interleaving String Hard 98 Validate Binary Search Tree Medium 99 Recover Binary Search Tree Hard 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 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 123 Best Time to Buy and Sell Stock III Hard 124 Binary Tree Maximum Path Sum Hard 125 Valid Palindrome Easy 126 Word Ladder II Hard 127 Word Ladder Medium 128 Longest Consecutive Sequence Hard 129 Sum Root to Leaf Numbers Medium 130 Surrounded Regions Medium 131 Palindrome Partitioning Medium 132 Palindrome Partitioning II Hard 134 Gas Station Medium 135 Candy Hard 136 Single Number Easy 137 Single Number II Medium 139 Word Break Medium 140 Word Break II Hard 141 Linked List Cycle Easy 142 Linked List Cycle II Medium 143 Reorder List Medium 144 Binary Tree Preorder Traversal Medium 145 Binary Tree Postorder Traversal Hard 146 LRU Cache Medium 147 Insertion Sort List Medium 148 Sort List Medium 149 Max Points on a Line Hard 150 Evaluate Reverse Polish Notation Medium 151 Reverse Words in a String 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 165 Compare Version Numbers Medium 166 Fraction to Recurring Decimal 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 173 Binary Search Tree Iterator Medium 174 Dungeon Game Hard 179 Largest Number Medium 187 Repeated DNA Sequences Medium 188 Best Time to Buy and Sell Stock IV Hard 189 Rotate Array Easy 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 201 Bitwise AND of Numbers Range Medium 202 Happy Number Easy 203 Remove Linked List Elements Easy 204 Count Primes Easy 205 Isomorphic Strings Easy 206 Reverse Linked List Easy 207 Course Schedule Medium 208 Implement Trie (Prefix Tree) Medium 209 Minimum Size Subarray Sum Medium 210 Course Schedule II 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 219 Contains Duplicate II Easy 220 Contains Duplicate III Medium 221 Maximal Square Medium 222 Count Complete Tree Nodes Medium 223 Rectangle Area Medium 225 Implement Stack using Queues Easy 226 Invert Binary Tree Easy 227 Basic Calculator II Medium 228 Summary Ranges Medium 229 Majority Element II Medium 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 236 Lowest Common Ancestor of a Binary Tree Medium 237 Delete Node in a Linked List Easy 238 Product of Array Except Self Medium 240 Search a 2D Matrix II Medium 241 Different Ways to Add Parentheses Medium 242 Valid Anagram Easy 257 Binary Tree Paths Easy 258 Add Digits Easy 260 Single Number III Medium 263 Ugly Number Easy 264 Ugly Number II Medium 268 Missing Number Easy 274 H-Index Medium 275 H-Index II Medium 279 Perfect Squares Medium 283 Move Zeroes Easy 287 Find the Duplicate Number Medium 289 Game of Life Medium 290 Word Pattern Easy 292 Nim Game Easy 299 Bulls and Cows Medium 300 Longest Increasing Subsequence Medium 303 Range Sum Query - Immutable Easy 304 Range Sum Query 2D - Immutable Medium 306 Additive Number Medium 307 Range Sum Query - Mutable Medium 322 Coin Change Medium 324 Wiggle Sort II Medium 326 Power of Three Easy 328 Odd Even Linked List Medium 332 Reconstruct Itinerary Medium 334 Increasing Triplet Subsequence 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 378 Kth Smallest Element in a Sorted Matrix Medium 380 Insert Delete GetRandom O(1) Medium 383 Ransom Note Easy 384 Shuffle an Array Medium 387 First Unique Character in a String Easy 389 Find the Difference Easy 392 Is Subsequence Easy 395 Longest Substring with At Least K Repeating Characters Medium 400 Nth Digit Easy 401 Binary Watch Easy 403 Frog Jump Hard 404 Sum of Left Leaves Easy 405 Convert a Number to Hexadecimal Easy 409 Longest Palindrome Easy 412 Fizz Buzz Easy 414 Third Maximum Number Easy 415 Add Strings Easy 434 Number of Segments in a String Easy 437 Path Sum III Easy 438 Find All Anagrams in a String Easy 441 Arranging Coins Easy 443 String Compression Easy 445 Add Two Numbers II Medium 447 Number of Boomerangs Easy 448 Find All Numbers Disappeared in an Array Easy 453 Minimum Moves to Equal Array Elements Easy 454 4Sum II Medium 455 Assign Cookies Easy 458 Poor Pigs Easy 459 Repeated Substring Pattern Easy 461 Hamming Distance Easy 463 Island Perimeter Easy 475 Heaters Easy 476 Number Complement Easy 479 Largest Palindrome Product Easy 482 License Key Formatting Easy 485 Max Consecutive Ones Easy 492 Construct the Rectangle Easy 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 509 Fibonacci Number Easy 520 Detect Capital Easy 521 Longest Uncommon Subsequence I Easy 530 Minimum Absolute Difference in BST Easy 532 K-diff Pairs in an Array Easy 538 Convert BST to Greater Tree Easy 541 Reverse String II Easy 543 Diameter of Binary Tree Easy 551 Student Attendance Record I Easy 557 Reverse Words in a String III Easy 561 Array Partition I Easy 563 Binary Tree Tilt Easy 566 Reshape the Matrix Easy 572 Subtree of Another Tree Easy 575 Distribute Candies Easy 581 Shortest Unsorted Continuous Subarray Easy 590 N-ary Tree Postorder Traversal Easy 594 Longest Harmonious Subsequence Easy 598 Range Addition II Easy 599 Minimum Index Sum of Two Lists Easy 604 Design Compressed String Iterator Easy 605 Can Place Flowers Easy 606 Construct String from Binary Tree Easy 617 Merge Two Binary Trees Easy 624 Maximum Distance in Arrays 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 644 Maximum Average Subarray II Hard 645 Set Mismatch Easy 646 Maximum Length of Pair Chain Medium 647 Palindromic Substrings Medium 648 Replace Words Medium 653 Two Sum IV - Input is a BST Easy 654 Maximum Binary Tree Medium 655 Print Binary Tree Medium 657 Judge Route Circle Easy 658 Find K Closest Elements Medium 661 Image Smoother Easy 662 Maximum Width of Binary Tree Medium 665 Non-decreasing Array Easy 669 Trim a Binary Search Tree Easy 670 Maximum Swap Medium 671 Second Minimum Node In a Binary Tree Easy 674 Longest Continuous Increasing Subsequence Easy 680 Valid Palindrome II Easy 682 Baseball Game Easy 686 Repeated String Match Easy 687 Longest Univalue Path Easy 693 Binary Number with Alternating Bits Easy 695 Max Area of Island Easy 696 Count Binary Substrings Easy 697 Degree of an Array Easy 700 Search in a Binary Search Tree Easy 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 709 To Lower Case Easy 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 733 Flood Fill Easy 734 Sentence Similarity Easy 737 Sentence Similarity II Medium 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 760 Find Anagram Mappings Easy 762 Prime Number of Set Bits in Binary Representation Easy 766 Toeplitz Matrix Easy 771 Jewels and Stones Easy 783 Minimum Distance Between BST Nodes Easy 784 Letter Case Permutation Easy 788 Rotated Digits Easy 804 Unique Morse Code Words Easy 806 Number of Lines To Write String Easy 811 Subdomain Visit Count Easy 812 Largest Triangle Area Easy 817 Linked List Components Medium 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 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 867 Transpose Matrix Easy 872 Leaf-Similar Trees Easy 876 Middle of the Linked List Easy 883 Projection Area of 3D Shapes Easy 884 Uncommon Words from Two Sentences Easy 888 Fair Candy Swap Easy 892 Surface Area of 3D Shapes Easy 893 Groups of Special-Equivalent Strings Easy 896 Monotonic Array Easy 897 Increasing Order Search Tree Easy 905 Sort Array By Parity Easy 908 Smallest Range I Easy 914 X of a Kind in a Deck of Cards Easy 917 Reverse Only Letters Easy 922 Sort Array By Parity II Easy 925 Long Pressed Name Easy 929 Unique Email Addresses Easy 937 Reorder Log Files Easy 941 Valid Mountain Array Easy 942 DI String Match Easy 944 Delete Columns to Make Sorted Easy 949 Largest Time for Given Digits Easy 953 Verifying an Alien Dictionary Easy 961 N-Repeated Element in Size 2N Array Easy 965 Univalued Binary Tree Easy 970 Powerful Integers Easy 973 K Closest Points to Origin Easy 976 Largest Perimeter Triangle Easy 977 Squares of a Sorted Array Easy 984 String Without AAA or BBB Easy 985 Sum of Even Numbers After Queries Easy 989 Add to Array-Form of Integer Easy 993 Cousins in Binary Tree Easy 994 Rotting Oranges Easy 997 Find the Town Judge Easy 999 Available Captures for Rook Easy 1002 Find Common Characters Easy 1025 Divisor Game Easy