LeetCode

LeetCode Problems

题号	标题	代码	题解	难度	备注
1	Two Sum	Java	题解	Easy
2	Add Two Numbers	Java	题解	Medium
3	Longest Substring Without Repeating Characters	Java	题解	Medium
4	Median of Two Sorted Arrays	Java	题解	Hard
5	Longest Palindromic Substring	Java	题解	Medium
6	ZigZag Conversion	Java	题解	Medium
7	Reverse Integer	Java	题解	Easy
8	String to Integer (atoi)	Java	题解	Medium
9	Palindrome Number	Java	题解	Easy
11	Container With Most Water	Java	题解	Medium
12	Integer to Roman	Java	题解	Medium
13	Roman to Integer	Java	题解	Easy
14	Longest Common Prefix	Java	题解	Easy
15	3Sum	Java	题解	Medium
16	3Sum Closest	Java	题解	Medium
17	Letter Combinations of a Phone Number	Java	题解	Medium
18	4Sum	Java	题解	Medium
19	Remove Nth Node From End of List	Java	题解	Medium
20	Valid Parentheses	Java	题解	Easy
21	Merge Two Sorted Lists	Java	题解	Easy
22	Generate Parentheses	Java	题解	Medium
23	Merge k Sorted Lists	Java	题解	Hard
24	Swap Nodes in Pairs	Java	题解	Medium
26	Remove Duplicates from Sorted Array	Java	题解	Easy
27	Remove Element	Java	题解	Easy
28	Implement strStr()	Java	题解	Easy
29	Divide Two Integers	Java	题解	Medium
31	Next Permutation	Java	题解	Medium
33	Search in Rotated Sorted Array	Java	题解	Medium
34	Find First and Last Position of Element in Sorted Array	Java	题解	Medium
35	Search Insert Position	Java	题解	Easy
36	Valid Sudoku	Java	题解	Medium
38	Count and Say	Java	题解	Easy
39	Combination Sum	Java	题解	Medium
40	Combination Sum II	Java	题解	Medium
41	First Missing Positive	Java	题解	Hard
42	Trapping Rain Water	Java	题解	Hard
43	Multiply Strings	Java	题解	Medium
45	Jump Game II	Java	题解	Hard
46	Permutations	Java	题解	Medium
47	Permutations II	Java	题解	Medium
48	Rotate Image	Java	题解	Medium
49	Group Anagrams	Java	题解	Medium
50	Pow(x, n)	Java	题解	Medium
51	N-Queens	Java	题解	Hard
52	N-Queens II	Java	题解	Hard
53	Maximum Subarray	Java	题解	Easy
54	Spiral Matrix	Java	题解	Medium
55	Jump Game	Java	题解	Medium
56	Merge Intervals	Java	题解	Medium
58	Length of Last Word	Java	题解	Easy
59	Spiral Matrix II	Java	题解	Medium
60	Permutation Sequence	Java	题解	Medium
61	Rotate List	Java	题解	Medium
62	Unique Paths	Java	题解	Medium
63	Unique Paths II	Java	题解	Medium
64	Minimum Path Sum	Java	题解	Medium
66	Plus One	Java	题解	Easy
67	Add Binary	Java	题解	Easy
69	Sqrt(x)	Java	题解	Easy
70	Climbing Stairs	Java	题解	Easy
71	Simplify Path	Java	题解	Medium
73	Set Matrix Zeroes	Java	题解	Medium
75	Sort Colors	Java	题解	Medium
76	Minimum Window Substring	Java	题解	Hard
77	Combinations	Java	题解	Medium
78	Subsets	Java	题解	Medium
79	Word Search	Java	题解	Medium
80	Remove Duplicates from Sorted Array II	Java	题解	Medium
81	Search in Rotated Sorted Array II	Java	题解	Medium
82	Remove Duplicates from Sorted List II	Java	题解	Medium
83	Remove Duplicates from Sorted List	Java	题解	Easy
86	Partition List	Java	题解	Medium
88	Merge Sorted Array	Java	题解	Easy
89	Gray Code	Java	题解	Medium
90	Subsets II	Java	题解	Medium
91	Decode Ways	Java	题解	Medium
92	Reverse Linked List II	Java	题解	Medium
93	Restore IP Addresses	Java	题解	Medium
94	Binary Tree Inorder Traversal	Java	题解	Medium
95	Unique Binary Search Trees II	Java	题解	Medium
96	Unique Binary Search Trees	Java	题解	Medium
98	Validate Binary Search Tree	Java	题解	Medium	树形DP套路或中序遍历
99	Recover Binary Search Tree	Java	题解	Medium	Morris遍历
100	Same Tree	Java	题解	Easy
101	Symmetric Tree	Java	题解	Easy
102	Binary Tree Level Order Traversal	Java	题解	Medium
103	Binary Tree Zigzag Level Order Traversal	Java	题解	Medium
104	Maximum Depth of Binary Tree	Java	题解	Easy
105	Construct Binary Tree from Preorder and Inorder Traversal	Java	题解	Medium	迭代如何实现？
106	Construct Binary Tree from Inorder and Postorder Traversal	Java	题解	Medium	迭代如何实现？
107	Binary Tree Level Order Traversal II	Java	题解	Easy
108	Convert Sorted Array to Binary Search Tree	Java	题解	Easy
109	Convert Sorted List to Binary Search Tree``	Java	题解	Medium	分治+中序遍历
110	Balanced Binary Tree	Java	题解	Easy
111	Minimum Depth of Binary Tree	Java	题解	Easy	Morris解法需要深入研究
112	Path Sum	Java	题解	Easy
113	Path Sum II	Java	题解	Medium
114	Flatten Binary Tree to Linked List	Java	题解	Medium
116	Populating Next Right Pointers in Each Node	Java	题解	Medium
117	Populating Next Right Pointers in Each Node II	Java	题解	Medium
118	Pascal’s Triangle	Java	题解	Easy
119	Pascal’s Triangle II	Java	题解	Easy
120	Triangle	Java	题解	Medium
121	Best Time to Buy and Sell Stock	Java	题解	Easy
122	Best Time to Buy and Sell Stock II	Java	题解	Easy
123	Best Time to Buy and Sell Stock III	Java	题解	Hard
125	Valid Palindrome	Java	题解	Easy
127	Word Ladder	Java	题解	Medium
129	Sum Root to Leaf Numbers	Java	题解	Medium
130	Surrounded Regions	Java	题解	Medium
131	Palindrome Partitioning	Java	题解	Medium
133	Clone Graph	Java	题解	Medium
134	Gas Station	Java	题解	Medium
136	Single Number	Java	题解	Easy
138	Copy List with Random Pointer	Java	题解	Medium
139	Word Break	Java	题解	Medium
141	Linked List Cycle	Java	题解	Easy
142	Linked List Cycle II	Java	题解	Medium
144	Binary Tree Preorder Traversal	Java	题解	Medium
145	Binary Tree Postorder Traversal	Java	题解	Easy	强化迭代
146	LRU Cache	Java	题解	Medium
148	Sort List	Java	题解	Medium
150	Evaluate Reverse Polish Notation	Java	题解	Medium
152	Maximum Product Subarray	Java	题解	Medium
153	Find Minimum in Rotated Sorted Array	Java	题解	Medium
154	Find Minimum in Rotated Sorted Array II	Java	题解	Hard
155	Min Stack	Java	题解	Easy
160	Intersection of Two Linked Lists	Java	题解	Easy
162	Find Peak Element	Java	题解	Medium
166	Fraction to Recurring Decimal	Java	题解	Medium
167	Two Sum II - Input array is sorted	Java	题解	Easy
169	Majority Element	Java	题解	Easy
171	Excel Sheet Column Number	Java	题解	Easy
172	Factorial Trailing Zeroes	Java	题解	Easy
175	Combine Two Tables	SQL	题解	Easy
176	Second Highest Salary	SQL	题解	Easy
179	Largest Number	Java	题解	Medium
188	Best Time to Buy and Sell Stock IV	Java	题解	Hard
189	Rotate Array	Java	题解	Easy
190	Reverse Bits	Java	题解	Easy
191	Number of 1 Bits	Java	题解	Easy
198	House Robber	Java	题解	Easy
199	Binary Tree Right Side View	Java	题解	Medium	递归+DFS解法有意思
200	Number of Islands	Java	题解	Medium
202	Happy Number	Java	题解	Easy
204	Count Primes	Java	题解	Easy
206	Reverse Linked List	Java	题解	Easy
207	Course Schedule	Java	题解	Medium
208	Implement Trie (Prefix Tree)	Java	题解	Medium
210	Course Schedule II	Java	题解	Medium
215	Kth Largest Element in an Array	Java	题解	Medium
217	Contains Duplicate	Java	题解	Easy
221	Maximal Square	Java	题解	Medium
222	Count Complete Tree Nodes	Java	题解	Medium
226	Invert Binary Tree	Java	题解	Easy
227	Basic Calculator II	Java	题解	Medium
230	Kth Smallest Element in a BST	Java	题解	Medium
234	Palindrome Linked List	Java	题解	Easy
235	Lowest Common Ancestor of a Binary Search Tree	Java	题解	Easy	二叉搜索树左大右小的特性
236	Lowest Common Ancestor of a Binary Tree	Java	题解	Medium
237	Delete Node in a Linked List	Java	题解	Easy
238	Product of Array Except Self	Java	题解	Medium
239	Sliding Window Maximum	Java	题解	Hard
240	Search a 2D Matrix II	Java	题解	Medium
242	Valid Anagram	Java	题解	Easy
257	Binary Tree Paths	Java	题解	Easy
268	Missing Number	Java	题解	Easy
279	Perfect Squares	Java	题解	Medium
283	Move Zeroes	Java	题解	Easy
287	Find the Duplicate Number	Java	题解	Medium
289	Game of Life	Java	题解	Medium
297	Serialize and Deserialize Binary Tree	Java	题解	Hard	注意思维误区！
300	Longest Increasing Subsequence	Java	题解	Medium
309	Best Time to Buy and Sell Stock with Cooldown	Java	题解	Medium
322	Coin Change	Java	题解	Medium
324	Wiggle Sort II	Java	题解	Medium
326	Power of Three	Java	题解	Easy
328	Odd Even Linked List	Java	题解	Medium
334	Increasing Triplet Subsequence	Java	题解	Medium
337	House Robber III	Java	题解	Medium
338	Counting Bits	Java	题解	Medium
341	Flatten Nested List Iterator	Java	题解	Medium
343	Integer Break	Java	题解	Medium
344	Reverse String	Java	题解	Easy
347	Top K Frequent Elements	Java	题解	Medium
350	Intersection of Two Arrays II	Java	题解	Easy
371	Sum of Two Integers	Java	题解	Easy
378	Kth Smallest Element in a Sorted Matrix	Java	题解	Medium
380	Insert Delete GetRandom O(1)	Java	题解	Medium
384	Shuffle an Array	Java	题解	Medium
387	First Unique Character in a String	Java	题解	Easy
394	Decode String	Java	题解	Medium
395	Longest Substring with At Least K Repeating Characters	Java	题解	Medium
406	Queue Reconstruction by Height	Java	题解	Medium
412	Fizz Buzz	Java	题解	Easy
416	Partition Equal Subset Sum	Java	题解	Medium
429	N-ary Tree Level Order Traversal	Java	题解	Medium	广度优先
437	Path Sum III	Java	题解	Medium	前缀和解法还需要多思考！
438	Find All Anagrams in a String	Java	题解	Medium
444	Sequence Reconstruction	Java	题解	Medium
448	Find All Numbers Disappeared in an Array	Java	题解	Easy
450	Delete Node in a BST	Java	题解	Medium
453	Minimum Moves to Equal Array Elements	Java	题解	Medium
454	4Sum II	Java	题解	Medium
462	Minimum Moves to Equal Array Elements II	Java	题解	Medium	快速选择
494	Target Sum	Java	题解	Medium
501	Find Mode in Binary Search Tree	Java	题解	Easy
509	Fibonacci Number	Java	题解	Easy
513	Find Bottom Left Tree Value	Java	题解	Medium
515	Find Largest Value in Each Tree Row	Java	题解	Medium	层序遍历
523	Continuous Subarray Sum	Java	题解	Medium	前缀和
530	Minimum Absolute Difference in BST	Java	题解	Easy
538	Convert BST to Greater Tree	Java	题解	Easy
543	Diameter of Binary Tree	Java	题解	Easy
560	Subarray Sum Equals K	Java	题解	Medium	前缀和
567	Permutation in String	Java	题解	Medium
581	Shortest Unsorted Continuous Subarray	Java	题解	Easy
617	Merge Two Binary Trees	Java	题解	Easy
621	Task Scheduler	Java	题解	Medium
647	Palindromic Substrings	Java	题解	Medium
654	Maximum Binary Tree	Java	题解	Medium
669	Trim a Binary Search Tree	Java	题解	Easy
700	Search in a Binary Search Tree	Java	题解	Easy
701	Insert into a Binary Search Tree	Java	题解	Medium
704	Binary Search	Java	题解	Easy
713	Subarray Product Less Than K	Java	题解	Medium	滑动窗口
714	Best Time to Buy and Sell Stock with Transaction Fee	Java	题解	Medium
752	Open the Lock	Java	题解	Medium
876	Middle of the Linked List	Java	题解	Easy
992	Subarrays with K Different Integers	Java	题解	Hard