My LeetCode solutions with Chinese explanation. 我的LeetCode中文题解。
每个题目都保证击败超过80%的提交，并尽量给出多种解法并分析算法复杂度。
每日持续更新中，欢迎交流，欢迎star :D

另外，

# 题目 题解 难度  
1 Two Sum C++ Easy  
2 Add Two Numbers C++ Medium  
3 Longest Substring Without Repeating Characters C++ Medium  
4 Median of Two Sorted Arrays C++ Hard  
5 Longest Palindromic Substring C++ Medium  
6 ZigZag Conversion C++ Medium  
7 Reverse Integer C++ Easy  
8 String to Integer (atoi) C++ Medium  
9 Palindrome Number C++ Easy  
10 Regular Expression Matching C++ Hard  
11 Container With Most Water C++ Medium  
12 Integer to Roman C++ Medium  
13 Roman to Integer C++ Easy  
14 Longest Common Prefix C++ Easy  
15 3Sum C++ Medium  
16 3Sum Closest C++ Medium  
17 Letter Combinations of a Phone Number C++ Medium  
18 4Sum C++ Medium  
19 Remove Nth Node From End of List C++ Medium  
20 Valid Parentheses C++ Easy  
21 Merge Two Sorted Lists C++ Easy  
22 Generate Parentheses C++ Medium  
23 Merge k Sorted Lists C++ Hard  
24 Swap Nodes in Pairs C++ Medium  
26 Remove Duplicates from Sorted Array C++ Easy  
27 Remove Element C++ Easy  
28 Implement strStr() C++ Easy  
29 Divide Two Integers C++ Medium  
31 Next Permutation C++ Medium  
32 Longest Valid Parentheses C++ Hard  
33 Search in Rotated Sorted Array C++ Medium  
34 Find First and Last Position of Element in Sorted C++ Medium  
35 Search Insert Position C++ Easy  
36 Valid Sudoku C++ Medium  
38 Count and Say C++ Easy  
39 Combination Sum C++ Medium  
40 Combination Sum II C++ Medium  
41 First Missing Positive C++ Hard  
42 Trapping Rain Water C++ Hard  
43 Multiply Strings C++ Medium  
44 Wildcard Matching C++ Hard  
45 Jump Game II C++ Hard  
46 Permutations C++ Medium  
47 Permutations II C++ Medium  
48 Rotate Image C++ Medium  
49 Group Anagrams C++ Medium  
50 Pow(x, n) C++ Medium  
53 Maximum Subarray C++ Easy  
54 Spiral Matrix C++ Medium  
55 Jump Game C++ Medium  
56 Merge Intervals C++ Medium  
58 Length of Last Word C++ Easy  
59 Spiral Matrix II C++ Medium  
60 Permutation Sequence C++ Medium  
61 Rotate List C++ Medium  
62 Unique Paths C++ Medium  
63 Unique Paths II C++ Medium  
64 Minimum Path Sum C++ Medium  
65 Valid Number C++ Hard  
66 Plus One C++ Easy  
67 Add Binary C++ Easy  
69 Sqrt(x) C++ Easy  
70 Climbing Stairs C++ Easy  
71 Simplify Path C++ Medium  
72 Edit Distance C++ Hard  
73 Set Matrix Zeroes C++ Medium  
74 Search a 2D Matrix C++ Medium  
75 Sort Colors C++ Medium  
76 Minimum Window Substring C++ Hard  
77 Combinations C++ Medium  
78 Subsets C++ Medium  
79 Word Search C++ Medium  
80 Remove Duplicates from Sorted Array II C++ Medium  
81 Search in Rotated Sorted Array II C++ Medium  
82 Remove Duplicates from Sorted List II C++ Medium  
83 Remove Duplicates from Sorted List C++ Easy  
84 Largest Rectangle in Histogram C++ Hard  
85 Maximal Rectangle C++ Hard  
86 Partition List C++ Medium  
88 Merge Sorted Array C++ Easy  
89 Gray Code C++ Medium  
90 Subsets II C++ Medium  
91 Decode Ways C++ Medium  
92 Reverse Linked List II C++ Medium  
93 Restore IP Addresses C++ Medium  
94 Binary Tree Inorder Traversal C++ Medium  
95 Unique Binary Search Trees II C++ Medium  
96 Unique Binary Search Trees C++ Medium  
97 Interleaving String C++ Medium  
98 Validate Binary Search Tree C++ Medium  
99 Recover Binary Search Tree C++ Medium  
100 Same Tree C++ Easy  
101 Symmetric Tree C++ Easy  
102 Binary Tree Level Order Traversal C++ Medium  
103 Binary Tree Zigzag Level Order Traversal C++ Medium  
104 Maximum Depth of Binary Tree C++ Easy  
105 Construct Binary Tree from Preorder and Inorder Traversal C++ Medium  
106 Construct Binary Tree from Inorder and Postorder Traversal C++ Medium  
107 Binary Tree Level Order Traversal II C++ Easy  
108 Convert Sorted Array to Binary Search Tree C++ Easy  
109 Convert Sorted List to Binary Search Tree C++ Medium  
110 Balanced Binary Tree C++ Easy  
111 Minimum Depth of Binary Tree C++ Easy  
112 Path Sum C++ Easy  
113 Path Sum II C++ Medium  
114 Flatten Binary Tree to Linked List C++ Medium  
116 Populating Next Right Pointers in Each Node C++ Medium  
117 Populating Next Right Pointers in Each Node II C++ Medium  
118 Pascal’s Triangle C++ Easy  
119 Pascal’s Triangle II C++ Easy  
120 Triangle C++ Medium  
121 Best Time to Buy and Sell Stock C++ Easy  
122 Best Time to Buy and Sell Stock II C++ Easy  
123 Best Time to Buy and Sell Stock III C++ Hard  
124 Binary Tree Maximum Path Sum C++ Hard  
125 Valid Palindrome C++ Easy  
127 Word Ladder C++ Medium  
128 Longest Consecutive Sequence C++ Hard  
129 Sum Root to Leaf Numbers C++ Medium  
130 Surrounded Regions C++ Medium  
131 Palindrome Partitioning C++ Medium  
133 Clone Graph C++ Medium  
134 Gas Station C++ Medium  
136 Single Number C++ Easy  
137 Single Number II C++ Medium  
138 Copy List with Random Pointer C++ Medium  
139 Word Break C++ Medium  
140 Word Break II C++ Hard  
141 Linked List Cycle C++ Easy  
142 Linked List Cycle II C++ Medium  
143 Reorder List C++ Medium  
144 Binary Tree Preorder Traversal C++ Medium  
145 Binary Tree Postorder Traversal C++ Hard  
146 LRU Cache C++ Medium  
148 Sort List C++ Medium  
149 Max Points on a Line C++ Hard  
150 Evaluate Reverse Polish Notation C++ Medium  
151 Reverse Words in a String C++ Medium  
152 Maximum Product Subarray C++ Medium  
153 Find Minimum in Rotated Sorted Array C++ Medium  
155 Min Stack C++ Easy  
160 Intersection of Two Linked Lists C++ Easy  
162 Find Peak Element C++ Medium  
165 Compare Version Numbers C++ Medium  
166 Fraction to Recurring Decimal C++ Medium  
167 Two Sum II - Input array is sorted C++ Easy  
168 Excel Sheet Column Title C++ Easy  
169 Majority Element C++ Easy  
171 Excel Sheet Column Number C++ Easy  
172 Factorial Trailing Zeroes C++ Easy  
179 Largest Number C++ Medium  
187 Repeated DNA Sequences C++ Medium  
188 Best Time to Buy and Sell Stock IV C++ Hard  
189 Rotate Array C++ Easy  
190 Reverse Bits C++ Easy  
191 Number of 1 Bits C++ Easy  
198 House Robber C++ Easy  
199 Binary Tree Right Side View C++ Medium  
200 Number of Islands C++ Medium  
201 Bitwise AND of Numbers Range C++ Medium  
202 Happy Number C++ Easy  
203 Remove Linked List Elements C++ Easy  
204 Count Primes C++ Easy  
205 Isomorphic Strings C++ Easy  
206 Reverse Linked List C++ Easy  
207 Course Schedule C++ Medium  
208 Implement Trie (Prefix Tree) C++ Medium  
209 Minimum Size Subarray Sum C++ Medium  
210 Course Schedule II C++ Medium  
211 Add and Search Word - Data structure design C++ Medium  
212 Word Search II C++ Hard  
213 House Robber II C++ Medium  
215 Kth Largest Element in an Array C++ Medium  
216 Combination Sum III C++ Medium  
217 Contains Duplicate C++ Easy  
218 The Skyline Problem C++ Hard  
219 Contains Duplicate II C++ Easy  
220 Contains Duplicate III C++ Medium  
221 Maximal Square C++ Medium  
222 Count Complete Tree Nodes C++ Medium  
223 Rectangle Area C++ Medium  
225 Implement Stack using Queues C++ Easy  
226 Invert Binary Tree C++ Easy  
227 Basic Calculator II C++ Medium  
228 Summary Ranges C++ Medium  
229 Majority Element II C++ Medium  
230 Kth Smallest Element in a BST C++ Medium  
231 Power of Two C++ Easy  
232 Implement Queue using Stacks C++ Easy  
233 Number of Digit One C++ Hard  
234 Palindrome Linked List C++ Easy  
235 Lowest Common Ancestor of a Binary Search Tree C++ Easy  
236 Lowest Common Ancestor of a Binary Tree C++ Medium  
237 Delete Node in a Linked List C++ Easy  
238 Product of Array Except Self C++ Medium  
239 Sliding Window Maximum C++ Hard  
240 Search a 2D Matrix II C++ Medium  
241 Different Ways to Add Parentheses C++ Medium  
242 Valid Anagram C++ Easy  
257 Binary Tree Paths C++ Easy  
258 Add Digits C++ Easy  
260 Single Number III C++ Medium  
263 Ugly Number C++ Easy  
264 Ugly Number II C++ Medium  
268 Missing Number C++ Easy  
274 H-Index C++ Medium  
275 H-Index II C++ Medium  
278 First Bad Version C++ Easy  
279 Perfect Squares C++ Medium  
283 Move Zeroes C++ Easy  
284 Peeking Iterator C++ Medium  
287 Find the Duplicate Number C++ Medium  
289 Game of Life C++ Medium  
290 Word Pattern C++ Easy  
292 Nim Game C++ Easy  
295 Find Median from Data Stream C++ Hard  
297 Serialize and Deserialize Binary Tree C++ Hard  
299 Bulls and Cows C++ Medium  
300 Longest Increasing Subsequence C++ Medium  
301 Remove Invalid Parentheses C++ Hard  
303 Range Sum Query - Immutable C++ Easy  
304 Range Sum Query 2D - Immutable C++ Medium  
306 Additive Number C++ Medium  
307 Range Sum Query - Mutable C++ Medium  
309 Best Time to Buy and Sell Stock with Cooldown C++ Medium  
310 Minimum Height Trees C++ Medium  
312 Burst Balloons C++ Hard  
313 Super Ugly Number C++ Medium  
315 Count of Smaller Numbers After Self C++ Hard  
316 Remove Duplicate Letters C++ Medium  
318 Maximum Product of Word Lengths C++ Medium  
319 Bulb Switcher C++ Medium  
322 Coin Change C++ Medium  
324 Wiggle Sort II C++ Medium  
326 Power of Three C++ Easy  
328 Odd Even Linked List C++ Medium  
329 Longest Increasing Path in a Matrix C++ Hard  
331 Verify Preorder Serialization of a Binary Tree C++ Medium  
332 Reconstruct Itinerary C++ Medium  
334 Increasing Triplet Subsequence C++ Medium  
337 House Robber III C++ Medium  
338 Counting Bits C++ Medium  
341 Flatten Nested List Iterator C++ Medium  
342 Power of Four C++ Easy  
343 Integer Break C++ Medium  
344 Reverse String C++ Easy  
345 Reverse Vowels of a String C++ Easy  
347 Top K Frequent Elements C++ Medium  
349 Intersection of Two Arrays C++ Easy  
350 Intersection of Two Arrays II C++ Easy  
357 Count Numbers with Unique Digits C++ Medium  
365 Water and Jug Problem C++ Medium  
367 Valid Perfect Square C++ Easy  
368 Largest Divisible Subset C++ Medium  
371 Sum of Two Integers C++ Easy  
372 Super Pow C++ Medium  
373 Find K Pairs with Smallest Sums C++ Medium  
374 Guess Number Higher or Lower C++ Easy  
375 Guess Number Higher or Lower II C++ Medium  
376 Wiggle Subsequence C++ Medium  
377 Combination Sum IV C++ Medium  
378 Kth Smallest Element in a Sorted Matrix C++ Medium  
380 Insert Delete GetRandom O(1) C++ Medium  
381 Insert Delete GetRandom O(1) - Duplicates allowed C++ Hard  
382 Linked List Random Node C++ Medium  
383 Ransom Note C++ Easy  
384 Shuffle an Array C++ Medium  
385 Mini Parser C++ Medium  
386 Lexicographical Numbers C++ Medium  
387 First Unique Character in a String C++ Easy  
388 Longest Absolute File Path C++ Medium  
389 Find the Difference C++ Easy  
390 Elimination Game C++ Medium  
392 Is Subsequence C++ Easy  
393 UTF-8 Validation C++ Medium  
394 Decode String C++ Medium  
395 Longest Substring with At Least K Repeating Characters C++ Medium  
396 Rotate Function C++ Medium  
397 Integer Replacement C++ Medium  
398 Random Pick Index C++ Medium  
400 Nth Digit C++ Medium  
401 Binary Watch C++ Easy  
402 Remove K Digits C++ Medium  
404 Sum of Left Leaves C++ Easy  
405 Convert a Number to Hexadecimal C++ Easy  
406 Queue Reconstruction by Height C++ Medium  
409 Longest Palindrome C++ Easy  
412 Fizz Buzz C++ Easy  
413 Arithmetic Slices C++ Medium  
414 Third Maximum Number C++ Easy  
415 Add Strings C++ Easy  
416 Partition Equal Subset Sum C++ Medium  
429 N-ary Tree Level Order Traversal C++ Easy  
434 Number of Segments in a String C++ Easy  
437 Path Sum III C++ Easy  
438 Find All Anagrams in a String C++ Easy  
441 Arranging Coins C++ Easy  
443 String Compression C++ Easy  
447 Number of Boomerangs C++ Easy  
448 Find All Numbers Disappeared in an Array C++ Easy  
453 Minimum Moves to Equal Array Elements C++ Easy  
454 4Sum II C++ Medium  
455 Assign Cookies C++ Easy  
459 Repeated Substring Pattern C++ Easy  
461 Hamming Distance C++ Easy  
463 Island Perimeter C++ Easy  
474 Ones and Zeroes C++ Medium  
475 Heaters C++ Easy  
476 Number Complement C++ Easy  
485 Max Consecutive Ones C++ Easy  
493 Reverse Pairs C++ Hard  
494 Target Sum C++ Medium  
496 Next Greater Element I C++ Easy  
500 Keyboard Row C++ Easy  
509 Fibonacci Number C++ Easy  
532 K-diff Pairs in an Array C++ Easy  
543 Diameter of Binary Tree C++ Easy  
560 Subarray Sum Equals K C++ Medium  
561 Array Partition I C++ Easy  
566 Reshape the Matrix C++ Easy  
572 Subtree of Another Tree C++ Easy  
581 Shortest Unsorted Continuous Subarray C++ Easy  
605 Can Place Flowers C++ Easy  
617 Merge Two Binary Trees C++ Easy  
621 Task Scheduler C++ Medium  
628 Maximum Product of Three Numbers C++ Easy  
643 Maximum Average Subarray I C++ Easy  
647 Palindromic Substrings C++ Medium  
661 Image Smoother C++ Easy  
665 Non-decreasing Array C++ Easy  
714 Best Time to Buy and Sell Stock with Transaction Fee C++ Medium  
739 Daily Temperatures C++ Medium  
829 Consecutive Numbers Sum C++ Hard  
846 Hand of Straights C++ Medium  
905 Sort Array By Parity C++ Easy  
946 Validate Stack Sequences C++ Medium  
1155 Number of Dice Rolls With Target Sum C++ Medium