LeetCode 算法题目解答
为了督促自己能够每天刷一道算法题，特将LeetCode常见题目列出，之后每天一题，每完成一题都会总结解答并链接到该博客相应的题目上。
| Title | Difficulty | |
|---|---|---|
| Palindrome Number | Easy (2) | |
| ZigZag Conversion | Easy (3) | |
| Valid Sudoku | Easy (2) | |
| Add Binary | Easy (2) | |
| Valid Parentheses | Easy (2) | |
| Valid Palindrome | Easy (2) | |
| Balanced Binary Tree | Easy (1) | |
| Valid Number | Easy (2) | |
| Symmetric Tree | Easy (1) | |
| String to Integer (atoi) | Easy (2) | |
| Same Tree | Easy (1) | |
| Binary Tree Level Order Traversal | Easy (3) | |
| Binary Tree Level Order Traversal II | Easy (3) | |
| Roman to Integer | Easy (2) | |
| Reverse Integer | Easy (2) | |
| Remove Nth Node From End of List | Easy (2) | |
| Remove Element | Easy (1) | |
| Remove Duplicates from Sorted List | Easy (1) | |
| Climbing Stairs | Easy (2) | |
| Remove Duplicates from Sorted Array | Easy (1) | |
| Plus One | Easy (1) | |
| Path Sum | Easy (1) | |
| Pascal’s Triangle II | Easy (2) | |
| Pascal’s Triangle | Easy (2) | |
| Minimum Depth of Binary Tree | Easy (1) | |
| Merge Two Sorted Lists | Easy (2) | |
| Merge Sorted Array | Easy (2) | |
| Maximum Depth of Binary Tree | Easy (1) | |
| Longest Common Prefix | Easy (2) | |
| Count and Say | Easy (2) | |
| Length of Last Word | Easy (1) | |
| Implement strStr() | Easy (4) | |
| Divide Two Integers | Medium (4) | |
| 3Sum | Medium (3) | |
| Evaluate Reverse Polish Notation | Medium | |
| Find Minimum in Rotated Sorted Array | Medium | |
| Word Search | Medium (3) | |
| Word Ladder | Medium (3) | |
| Flatten Binary Tree to Linked List | Medium (3) | |
| Gas Station | Medium | |
| Generate Parentheses | Medium (3) | |
| Gray Code | Medium (4) | |
| Word Break | Medium | |
| Validate Binary Search Tree | Medium (3) | |
| Insertion Sort List | Medium | |
| Integer to Roman | Medium (3) | |
| 4Sum | Medium (3) | |
| Jump Game | Medium (3) | |
| Add Two Numbers | Medium (3) | |
| Anagrams | Medium (3) | |
| Decode Ways | Medium (3) | |
| Letter Combinations of a Phone Number | Medium (3) | |
| Linked List Cycle | Medium | |
| Linked List Cycle II | Medium | |
| Best Time to Buy and Sell Stock | Medium (2) | |
| Unique Paths II | Medium (3) | |
| Longest Palindromic Substring | Medium (4) | |
| Longest Substring Without Repeating Characters | Medium (3) | |
| Unique Paths | Medium (2) | |
| Unique Binary Search Trees II | Medium (4) | |
| Unique Binary Search Trees | Medium (3) | |
| Two Sum | Medium (2) | |
| Convert Sorted List to Binary Search Tree | Medium (4) | |
| Maximum Product Subarray | Medium | |
| Maximum Subarray | Medium (3) | |
| Triangle | Medium (3) | |
| Best Time to Buy and Sell Stock II | Medium (3) | |
| Swap Nodes in Pairs | Medium (2) | |
| Convert Sorted Array to Binary Search Tree | Medium (2) | |
| Container With Most Water | Medium (3) | |
| Minimum Path Sum | Medium (3) | |
| Surrounded Regions | Medium (4) | |
| Multiply Strings | Medium (4) | |
| Sum Root to Leaf Numbers | Medium (2) | |
| Subsets II | Medium (4) | |
| Next Permutation | Medium (5) | |
| 3Sum Closest | Medium (3) | |
| Palindrome Partitioning | Medium (3) | |
| Subsets | Medium (3) | |
| Partition List | Medium (3) | |
| Construct Binary Tree from Inorder and Postorder Traversal | Medium | |
| Construct Binary Tree from Preorder and Inorder Traversal | Medium | |
| Combinations | Medium (3) | |
| Combination Sum II | Medium (4) | |
| Path Sum II | Medium (2) | |
| Permutation Sequence | Medium (5) | |
| Permutations | Medium (3) | |
| Sqrt(x) | Medium (4) | |
| Combination Sum | Medium (3) | |
| Populating Next Right Pointers in Each Node | Medium (3) | |
| Spiral Matrix II | Medium (3) | |
| Pow(x, n) | Medium (3) | |
| Spiral Matrix | Medium (4) | |
| Sort List | Medium | |
| Clone Graph | Medium | |
| Remove Duplicates from Sorted Array II | Medium (2) | |
| Sort Colors | Medium (4) | |
| Remove Duplicates from Sorted List II | Medium (3) | |
| Binary Tree Zigzag Level Order Traversal | Medium (4) | |
| Binary Tree Preorder Traversal | Medium | |
| Reorder List | Medium | |
| Restore IP Addresses | Medium (3) | |
| Single Number II | Medium | |
| Reverse Linked List II | Medium (3) | |
| Single Number | Medium | |
| Reverse Words in a String | Medium | |
| Simplify Path | Medium (3) | |
| Rotate Image | Medium (4) | |
| Rotate List | Medium (3) | |
| Binary Tree Inorder Traversal | Medium (4) | |
| Set Matrix Zeroes | Medium (3) | |
| Search a 2D Matrix | Medium (3) | |
| Search for a Range | Medium (4) | |
| Search Insert Position | Medium (2) | |
| Search in Rotated Sorted Array II | Medium (5) | |
| Text Justification | Hard (4) | |
| Search in Rotated Sorted Array | Hard (4) | |
| Binary Tree Maximum Path Sum | Hard (4) | |
| Reverse Nodes in k-Group | Hard (4) | |
| Binary Tree Postorder Traversal | Hard | |
| Candy | Hard | |
| Edit Distance | Hard (4) | |
| Recover Binary Search Tree | Hard (4) | |
| Populating Next Right Pointers in Each Node II | Hard (4) | |
| Permutations II | Hard (4) | |
| Best Time to Buy and Sell Stock III | Hard (4) | |
| Palindrome Partitioning II | Hard (4) | |
| N-Queens II | Hard (4) | |
| Substring with Concatenation of All Words | Hard (3) | |
| Sudoku Solver | Hard (4) | |
| N-Queens | Hard (4) | |
| Minimum Window Substring | Hard (4) | |
| Merge k Sorted Lists | Hard (3) | |
| Merge Intervals | Hard (4) | |
| Scramble String | Hard (5) | |
| Trapping Rain Water | Hard (4) | |
| Median of Two Sorted Arrays | Hard (5) | |
| Maximal Rectangle | Hard (5) | |
| Max Points on a Line | Hard | |
| LRU Cache | Hard | |
| Longest Valid Parentheses | Hard (4) | |
| Longest Consecutive Sequence | Hard (4) | |
| Copy List with Random Pointer | Hard | |
| Largest Rectangle in Histogram | Hard (5) | |
| Jump Game II | Hard (4) | |
| Interleaving String | Hard (5) | |
| Insert Interval | Hard (4) | |
| Wildcard Matching | Hard (5) | |
| Distinct Subsequences | Hard (4) | |
| Word Break II | Hard | |
| First Missing Positive | Hard (5) | |
| Word Ladder II | Hard (1) | |
| Find Minimum in Rotated Sorted Array II | Hard | |
| Regular Expression Matching | Hard (5) | |
| Invert Binary Tree | Easy | |
| Implement Stack using Queues | Medium | |
| Basic Calculator | Medium | |
| Rectangle Area | Easy | |
| Count Complete Tree Nodes | Medium | |
| Maximal Square | Medium | |
| Contains Duplicate III | Medium | |
| Contains Duplicate II | Easy | |
| The Skyline Problem | Hard | |
| Contains Duplicate | Easy | |
| Combination Sum III | Medium | |
| Kth Largest Element in an Array | Medium | |
| Shortest Palindrome | Hard | |
| House Robber II | Medium | |
| Word Search II | Hard | |
| Add and Search Word – Data structure design | Medium | |
| Course Schedule II | Medium | |
| Minimum Size Subarray Sum | Medium | |
| Implement Trie (Prefix Tree) | Medium | |
| Course Schedule | Medium | |
| Reverse Linked List | Easy | |
| Isomorphic Strings | Easy | |
| Count Primes | Easy | |
| Remove Linked List Elements | Easy | |
| Happy Number | Easy | |
| Bitwise AND of Numbers Range | Medium | |
| Number of Islands | Medium | |
| Binary Tree Right Side View | Medium | |
| House Robber | Easy | |
| Number of 1 Bits | Easy | |
| Reverse Bits | Easy | |
| Rotate Array | Easy | |
| Best Time to Buy and Sell Stock IV | Hard | |
| Repeated DNA Sequences | Medium | |
| Reverse Words in a String II | Medium | |
| Largest Number | Medium | |
| Dungeon Game | Hard | |
| Binary Search Tree Iterator | Medium | |
| Factorial Trailing Zeroes | Easy | |
| Excel Sheet Column Number | Easy | |
| Two Sum III – Data structure design | Easy | |
| Majority Element | Easy | |
| Excel Sheet Column Title | Easy | |
| Two Sum II – Input array is sorted | Medium | |
| Fraction to Recurring Decimal | Medium | |
| Compare Version Numbers | Easy | |
| Maximum Gap | Hard | |
| Missing Ranges | Medium | |
| Find Peak Element | Medium | |
| One Edit Distance | Medium | |
| Intersection of Two Linked Lists | Easy | |
| Longest Substring with At Most Two Distinct Characters | Hard | |
| Read N Characters Given Read4 II – Call multiple times | Hard | |
| Read N Characters Given Read4 | Easy | |
| Binary Tree Upside Down | Medium | |
| Min Stack | Easy | |
| Minimum Height Trees | Medium | |
| Best Time to Buy and Sell Stock with Cooldown | Medium | |
| Range Sum Query – Mutable | Medium | |
| Additive Number | Medium | |
| Range Sum Query 2D – Immutable | Medium | |
| Range Sum Query – Immutable | Easy | |
| Remove Invalid Parentheses | Hard | |
| Longest Increasing Subsequence | Medium | |
| Bulls and Cows | Easy | |
| Serialize and Deserialize Binary Tree | Medium | |
| Find Median from Data Stream | Hard | |
| Nim Game | Easy | |
| Word Pattern | Easy | |
| Game of Life | Medium | |
| Find the Duplicate Number | Hard | |
| Peeking Iterator | Medium | |
| Move Zeroes | Easy | |
| Expression Add Operators | Hard | |
| Perfect Squares | Medium | |
| First Bad Version | Easy | |
| H-Index II | Medium | |
| H-Index | Medium | |
| Integer to English Words | Medium | |
| Missing Number | Medium | |
| Ugly Number II | Medium | |
| Ugly Number | Easy | |
| Single Number III | Medium | |
| Add Digits | Easy | |
| Binary Tree Paths | Easy | |
| Valid Anagram | Easy | |
| Different Ways to Add Parentheses | Medium | |
| Search a 2D Matrix II | Medium | |
| Sliding Window Maximum | Hard | |
| Product of Array Except Self | Medium | |
| Delete Node in a Linked List | Easy | |
| Lowest Common Ancestor of a Binary Tree | Medium | |
| Lowest Common Ancestor of a Binary Search Tree | Easy | |
| Palindrome Linked List | Easy | |
| Number of Digit One | Medium | |
| Implement Queue using Stacks | Easy | |
| Power of Two | Easy | |
| Kth Smallest Element in a BST | Medium | |
| Majority Element II | Medium | |
| Summary Ranges | Easy | |
| Basic Calculator II | Medium | |
| Sum of Two Integers | Easy | |
| Largest Divisible Subset | Medium | |
| Valid Perfect Square | Medium | |
| Water and Jug Problem | Medium | |
| Max Sum of Rectangle No Larger Than K | Hard | |
| Count Numbers with Unique Digits | Medium | |
| Design Twitter | Medium | |
| Russian Doll Envelopes | Hard | |
| Data Stream as Disjoint Intervals | Hard | |
| Intersection of Two Arrays II | Easy | |
| Intersection of Two Arrays | Easy | |
| Top K Frequent Elements | Medium | |
| Reverse Vowels of a String | Easy | |
| Reverse String | Easy | |
| Integer Break | Medium | |
| Power of Four | Easy | |
| Flatten Nested List Iterator | Medium | |
| Counting Bits | Medium | |
| House Robber III | Medium | |
| Palindrome Pairs | Hard | |
| Self Crossing | Hard | |
| Increasing Triplet Subsequence | Medium | |
| Reconstruct Itinerary | Medium | |
| Verify Preorder Serialization of a Binary Three | Medium | |
| Patching Arrays | Hard | |
| Longest Increasing Path in a Matrix | Hard | |
| Odd Even Linked List | Medium | |
| Count of Range Sum | Hard | |
| Power of Three | Easy | |
| Wiggle Sort II | Medium | |
| Coin Change | Medium | |
| Create Maximum Number | Hard | |
| Bulb Switcher | Medium | |
| Maximum Product of Word Lengths | Medium | |
| Remove Duplicate Letters | Hard | |
| Count of Smaller Numbers After Self | Hard | |
| Super Ugly Number | Medium | |
| Burst Balloons | Hard |
其他题目总结
| Title |
|---|
| Binary Tree Upside Down |
| Read N Characters Given Read4 |
| Read N Characters Given Read4 II – Call multiple times |
| Longest Substring with At Most Two Distinct Characters |
| One Edit Distance |
| Missing Ranges |
| Two Sum III – Data structure design |
| Reverse Words in a String II |
| Shortest Word Distance |
| Shortest Word Distance II |
| Shortest Word Distance III |
| Strobogrammatic Number |
| Strobogrammatic Number II |
| Strobogrammatic Number III |
| Group Shifted Strings |
| Count Univalue Subtrees |
| Flatten 2D Vector |
| Meeting Rooms |
| Meeting Rooms II |
| Factor Combinations |
| Verify Preorder Sequence in Binary Search Tree |
| Paint House |
| 3Sum Smaller |
| Graph Valid Tree |
| Paint House II |
| Palindrome Permutation |
| Palindrome Permutation II |
| Alien Dictionary |
| Closest Binary Search Tree Value |
| Encode and Decode Strings |
| Closest Binary Search Tree Value II |
| Paint Fence |
| Find the Celebrity |
| Wiggle Sort |
| Zigzag Iterator |
| Inorder Successor in BST |
| Walls and Gates |
| Unique Word Abbreviation |
| Word Pattern II |
| Flip Game |
| Flip Game II |
| Best Meeting Point |
| Binary Tree Longest Consecutive Sequence |