LeetCode

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LeetCode Problems

序号	标题	代码	题解	难度	备注
1	1. Two Sum	Java	题解	Easy
2	2. Add Two Numbers	Java	题解	Medium
3	3. Longest Substring Without Repeating Characters	Java	题解	Medium
4	4. Median of Two Sorted Arrays	Java	题解	Hard
5	5. Longest Palindromic Substring	Java	题解	Medium
6	6. ZigZag Conversion	Java	题解	Medium
7	7. Reverse Integer	Java	题解	Easy
8	8. String to Integer (atoi)	Java	题解	Medium
9	9. Palindrome Number	Java	题解	Easy
10	11. Container With Most Water	Java	题解	Medium
11	12. Integer to Roman	Java	题解	Medium
12	13. Roman to Integer	Java	题解	Easy
13	14. Longest Common Prefix	Java	题解	Easy
14	15. 3Sum	Java	题解	Medium	双指针
15	16. 3Sum Closest	Java	题解	Medium
16	17. Letter Combinations of a Phone Number	Java	题解	Medium
17	18. 4Sum	Java	题解	Medium	双指针
18	19. Remove Nth Node From End of List	Java	题解	Medium
19	20. Valid Parentheses	Java	题解	Easy
20	21. Merge Two Sorted Lists	Java	题解	Easy
21	22. Generate Parentheses	Java	题解	Medium
22	23. Merge k Sorted Lists	Java	题解	Hard
23	24. Swap Nodes in Pairs	Java	题解	Medium
24	25. Reverse Nodes in k-Group	Java	题解	Hard
25	26. Remove Duplicates from Sorted Array	Java	题解	Easy
26	27. Remove Element	Java	题解	Easy
27	28. Implement strStr()	Java	题解	Easy
28	29. Divide Two Integers	Java	题解	Medium
29	31. Next Permutation	Java	题解	Medium
30	33. Search in Rotated Sorted Array	Java	题解	Medium
31	34. Find First and Last Position of Element in Sorted Array	Java	题解	Medium
32	35. Search Insert Position	Java	题解	Easy
33	36. Valid Sudoku	Java	题解	Medium
34	37. Sudoku Solver	Java	题解	Hard
35	38. Count and Say	Java	题解	Easy
36	39. Combination Sum	Java	题解	Medium
37	40. Combination Sum II	Java	题解	Medium
38	41. First Missing Positive	Java	题解	Hard
39	42. Trapping Rain Water	Java	题解	Hard	单调栈
40	43. Multiply Strings	Java	题解	Medium
41	45. Jump Game II	Java	题解	Hard
42	46. Permutations	Java	题解	Medium
43	47. Permutations II	Java	题解	Medium
44	48. Rotate Image	Java	题解	Medium
45	49. Group Anagrams	Java	题解	Medium
46	50. Pow(x, n)	Java	题解	Medium
47	51. N-Queens	Java	题解	Hard
48	52. N-Queens II	Java	题解	Hard
49	53. Maximum Subarray	Java	题解	Easy
50	54. Spiral Matrix	Java	题解	Medium
51	55. Jump Game	Java	题解	Medium
52	56. Merge Intervals	Java	题解	Medium
53	57. Insert Interval	Java	题解	Hard
54	58. Length of Last Word	Java	题解	Easy
55	59. Spiral Matrix II	Java	题解	Medium
56	60. Permutation Sequence	Java	题解	Medium
57	61. Rotate List	Java	题解	Medium
58	62. Unique Paths	Java	题解	Medium
59	63. Unique Paths II	Java	题解	Medium
60	64. Minimum Path Sum	Java	题解	Medium
61	66. Plus One	Java	题解	Easy
62	67. Add Binary	Java	题解	Easy
63	69. Sqrt(x)	Java	题解	Easy
64	70. Climbing Stairs	Java	题解	Easy
65	71. Simplify Path	Java	题解	Medium
66	72. Edit Distance	Java	题解	Hard
67	73. Set Matrix Zeroes	Java	题解	Medium
68	75. Sort Colors	Java	题解	Medium
69	76. Minimum Window Substring	Java	题解	Hard
70	77. Combinations	Java	题解	Medium
71	78. Subsets	Java	题解	Medium
72	79. Word Search	Java	题解	Medium
73	80. Remove Duplicates from Sorted Array II	Java	题解	Medium
74	81. Search in Rotated Sorted Array II	Java	题解	Medium
75	82. Remove Duplicates from Sorted List II	Java	题解	Medium
76	83. Remove Duplicates from Sorted List	Java	题解	Easy
77	86. Partition List	Java	题解	Medium
78	88. Merge Sorted Array	Java	题解	Easy
79	89. Gray Code	Java	题解	Medium
80	90. Subsets II	Java	题解	Medium
81	91. Decode Ways	Java	题解	Medium
82	92. Reverse Linked List II	Java	题解	Medium
83	93. Restore IP Addresses	Java	题解	Medium
84	94. Binary Tree Inorder Traversal	Java	题解	Medium
85	95. Unique Binary Search Trees II	Java	题解	Medium
86	96. Unique Binary Search Trees	Java	题解	Medium
87	98. Validate Binary Search Tree	Java	题解	Medium	树形DP套路或中序遍历
88	99. Recover Binary Search Tree	Java	题解	Medium	Morris遍历
89	100. Same Tree	Java	题解	Easy
90	101. Symmetric Tree	Java	题解	Easy
91	102. Binary Tree Level Order Traversal	Java	题解	Medium
92	103. Binary Tree Zigzag Level Order Traversal	Java	题解	Medium
93	104. Maximum Depth of Binary Tree	Java	题解	Easy
94	105. Construct Binary Tree from Preorder and Inorder Traversal	Java	题解	Medium	迭代如何实现？
95	106. Construct Binary Tree from Inorder and Postorder Traversal	Java	题解	Medium	迭代如何实现？
96	107. Binary Tree Level Order Traversal II	Java	题解	Easy
97	108. Convert Sorted Array to Binary Search Tree	Java	题解	Easy
98	109. Convert Sorted List to Binary Search Tree	Java	题解	Medium	分治+中序遍历
99	110. Balanced Binary Tree	Java	题解	Easy
100	111. Minimum Depth of Binary Tree	Java	题解	Easy	Morris解法需要深入研究
101	112. Path Sum	Java	题解	Easy
102	113. Path Sum II	Java	题解	Medium
103	114. Flatten Binary Tree to Linked List	Java	题解	Medium
104	116. Populating Next Right Pointers in Each Node	Java	题解	Medium
105	117. Populating Next Right Pointers in Each Node II	Java	题解	Medium
106	118. Pascal’s Triangle	Java	题解	Easy
107	119. Pascal’s Triangle II	Java	题解	Easy
108	120. Triangle	Java	题解	Medium
109	121. Best Time to Buy and Sell Stock	Java	题解	Easy
110	122. Best Time to Buy and Sell Stock II	Java	题解	Easy
111	123. Best Time to Buy and Sell Stock III	Java	题解	Hard
112	124. Binary Tree Maximum Path Sum	Java	题解	Hard
113	125. Valid Palindrome	Java	题解	Easy
114	127. Word Ladder	Java	题解	Medium
115	129. Sum Root to Leaf Numbers	Java	题解	Medium
116	130. Surrounded Regions	Java	题解	Medium
117	131. Palindrome Partitioning	Java	题解	Medium
118	133. Clone Graph	Java	题解	Medium
119	134. Gas Station	Java	题解	Medium
120	135. Candy	Java	题解	Hard
121	136. Single Number	Java	题解	Easy
122	137. Single Number II	Java	题解	Medium
123	138. Copy List with Random Pointer	Java	题解	Medium
124	139. Word Break	Java	题解	Medium
125	141. Linked List Cycle	Java	题解	Easy
126	142. Linked List Cycle II	Java	题解	Medium
127	144. Binary Tree Preorder Traversal	Java	题解	Medium
128	145. Binary Tree Postorder Traversal	Java	题解	Easy	强化迭代
129	146. LRU Cache	Java	题解	Medium
130	148. Sort List	Java	题解	Medium
131	150. Evaluate Reverse Polish Notation	Java	题解	Medium
132	151. Reverse Words in a String	Java	题解	Medium
133	152. Maximum Product Subarray	Java	题解	Medium
134	153. Find Minimum in Rotated Sorted Array	Java	题解	Medium
135	154. Find Minimum in Rotated Sorted Array II	Java	题解	Hard
136	155. Min Stack	Java	题解	Easy
137	160. Intersection of Two Linked Lists	Java	题解	Easy
138	162. Find Peak Element	Java	题解	Medium
139	166. Fraction to Recurring Decimal	Java	题解	Medium
140	167. Two Sum II - Input array is sorted	Java	题解	Easy
141	169. Majority Element	Java	题解	Easy
142	171. Excel Sheet Column Number	Java	题解	Easy
143	172. Factorial Trailing Zeroes	Java	题解	Easy
144	175. Combine Two Tables	SQL	题解	Easy
145	176. Second Highest Salary	SQL	题解	Easy
146	179. Largest Number	Java	题解	Medium
147	188. Best Time to Buy and Sell Stock IV	Java	题解	Hard
148	189. Rotate Array	Java	题解	Easy
149	190. Reverse Bits	Java	题解	Easy
150	191. Number of 1 Bits	Java	题解	Easy
151	198. House Robber	Java	题解	Easy
152	199. Binary Tree Right Side View	Java	题解	Medium	递归+DFS解法有意思
153	200. Number of Islands	Java	题解	Medium
154	202. Happy Number	Java	题解	Easy
155	204. Count Primes	Java	题解	Easy
156	205. Isomorphic Strings	Java	题解	Easy
157	206. Reverse Linked List	Java	题解	Easy
158	207. Course Schedule	Java	题解	Medium
159	208. Implement Trie (Prefix Tree)	Java	题解	Medium
160	210. Course Schedule II	Java	题解	Medium
161	215. Kth Largest Element in an Array	Java	题解	Medium
162	217. Contains Duplicate	Java	题解	Easy
163	221. Maximal Square	Java	题解	Medium
164	222. Count Complete Tree Nodes	Java	题解	Medium
165	226. Invert Binary Tree	Java	题解	Easy
166	227. Basic Calculator II	Java	题解	Medium
167	230. Kth Smallest Element in a BST	Java	题解	Medium
168	231. Power of Two	Java	题解	Easy
169	232. Implement Queue using Stacks	Java	题解	Easy
170	234. Palindrome Linked List	Java	题解	Easy
171	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
172	236. Lowest Common Ancestor of a Binary Tree	Java	题解	Medium
173	237. Delete Node in a Linked List	Java	题解	Easy
174	238. Product of Array Except Self	Java	题解	Medium
175	239. Sliding Window Maximum	Java	题解	Hard
176	240. Search a 2D Matrix II	Java	题解	Medium
177	242. Valid Anagram	Java	题解	Easy
178	257. Binary Tree Paths	Java	题解	Easy
179	268. Missing Number	Java	题解	Easy
180	278. First Bad Version	Java	题解	Easy
181	279. Perfect Squares	Java	题解	Medium
182	283. Move Zeroes	Java	题解	Easy
183	287. Find the Duplicate Number	Java	题解	Medium
184	289. Game of Life	Java	题解	Medium
185	295. Find Median from Data Stream	Java	题解	Hard
186	297. Serialize and Deserialize Binary Tree	Java	题解	Hard	注意思维误区！
187	300. Longest Increasing Subsequence	Java	题解	Medium
188	303. Range Sum Query - Immutable	Java	题解	Easy
189	304. Range Sum Query 2D - Immutable	Java	题解	Medium
190	309. Best Time to Buy and Sell Stock with Cooldown	Java	题解	Medium
191	316. Remove Duplicate Letters	Java	题解	Hard
192	322. Coin Change	Java	题解	Medium
193	324. Wiggle Sort II	Java	题解	Medium
194	326. Power of Three	Java	题解	Easy
195	328. Odd Even Linked List	Java	题解	Medium
196	334. Increasing Triplet Subsequence	Java	题解	Medium
197	337. House Robber III	Java	题解	Medium
198	338. Counting Bits	Java	题解	Medium
199	341. Flatten Nested List Iterator	Java	题解	Medium
200	343. Integer Break	Java	题解	Medium
201	344. Reverse String	Java	题解	Easy
202	347. Top K Frequent Elements	Java	题解	Medium
203	350. Intersection of Two Arrays II	Java	题解	Easy
204	370. Range Addition	Java	题解	Medium	Plus专题
205	371. Sum of Two Integers	Java	题解	Easy
206	378. Kth Smallest Element in a Sorted Matrix	Java	题解	Medium
207	380. Insert Delete GetRandom O(1)	Java	题解	Medium
208	384. Shuffle an Array	Java	题解	Medium
209	387. First Unique Character in a String	Java	题解	Easy
210	392. Is Subsequence	Java	题解	Easy
211	394. Decode String	Java	题解	Medium
212	395. Longest Substring with At Least K Repeating Characters	Java	题解	Medium
213	400. Nth Digit	Java	题解	Medium
214	402. Remove K Digits	Java	题解	Medium
215	404. Sum of Left Leaves	Java	题解	Easy
216	406. Queue Reconstruction by Height	Java	题解	Medium
217	409. Longest Palindrome	Java	题解	Easy
218	412. Fizz Buzz	Java	题解	Easy
219	415. Add Strings	Java	题解	Easy
220	416. Partition Equal Subset Sum	Java	题解	Medium
221	429. N-ary Tree Level Order Traversal	Java	题解	Medium	广度优先
222	437. Path Sum III	Java	题解	Medium	前缀和解法还需要多思考！
223	438. Find All Anagrams in a String	Java	题解	Medium
224	448. Find All Numbers Disappeared in an Array	Java	题解	Easy
225	450. Delete Node in a BST	Java	题解	Medium
226	453. Minimum Moves to Equal Array Elements	Java	题解	Medium
227	454. 4Sum II	Java	题解	Medium
228	462. Minimum Moves to Equal Array Elements II	Java	题解	Medium	快速选择
229	474. Ones and Zeroes	Java	题解	Medium
230	480. Sliding Window Median	Java	题解	Hard
231	494. Target Sum	Java	题解	Medium
232	496. Next Greater Element I	Java	题解	Easy
233	501. Find Mode in Binary Search Tree	Java	题解	Easy
234	503. Next Greater Element II	Java	题解	Medium
235	509. Fibonacci Number	Java	题解	Easy
236	513. Find Bottom Left Tree Value	Java	题解	Medium
237	515. Find Largest Value in Each Tree Row	Java	题解	Medium	层序遍历
238	523. Continuous Subarray Sum	Java	题解	Medium	前缀和
239	528. Random Pick with Weight	Java	题解	Medium
240	530. Minimum Absolute Difference in BST	Java	题解	Easy
241	538. Convert BST to Greater Tree	Java	题解	Easy
242	543. Diameter of Binary Tree	Java	题解	Easy
243	547. 省份数量	Java	题解	Medium
244	559. Maximum Depth of N-ary Tree	Java	题解	Easy
245	560. Subarray Sum Equals K	Java	题解	Medium	前缀和
246	567. Permutation in String	Java	题解	Medium
247	581. Shortest Unsorted Continuous Subarray	Java	题解	Easy
248	617. Merge Two Binary Trees	Java	题解	Easy
249	621. Task Scheduler	Java	题解	Medium
250	637. Average of Levels in Binary Tree	Java	题解	Easy
251	647. Palindromic Substrings	Java	题解	Medium
252	654. Maximum Binary Tree	Java	题解	Medium
253	669. Trim a Binary Search Tree	Java	题解	Easy
254	695. Max Area of Island	Java	题解	Medium
255	698. Partition to K Equal Sum Subsets	Java	题解	Medium
256	700. Search in a Binary Search Tree	Java	题解	Easy
257	701. Insert into a Binary Search Tree	Java	题解	Medium
258	704. Binary Search	Java	题解	Easy
259	710. Random Pick with Blacklist	Java	题解	Hard
260	713. Subarray Product Less Than K	Java	题解	Medium	滑动窗口
261	714. Best Time to Buy and Sell Stock with Transaction Fee	Java	题解	Medium
262	718. Maximum Length of Repeated Subarray	Java	题解	Medium
263	724. Find Pivot Index	Java	题解	Easy
264	739. Daily Temperatures	Java	题解	Medium
265	744. Find Smallest Letter Greater Than Target	Java	题解	Easy
266	746. Min Cost Climbing Stairs	Java	题解	Easy
267	752. Open the Lock	Java	题解	Medium
268	768. Max Chunks To Make Sorted II	Java	题解	Hard
269	796. Rotate String	Java	题解	Easy
270	869. Reordered Power of 2	Java	题解	Medium
271	870. Advantage Shuffle	Java	题解	Medium
272	875. Koko Eating Bananas	Java	题解	Medium	二分查找
273	876. Middle of the Linked List	Java	题解	Easy
274	881. Boats to Save People	Java	题解	Medium
275	892. Surface Area of 3D Shapes	Java	题解	Easy
276	904. Fruit Into Baskets	Java	题解	Medium
277	912. Sort an Array	Java	题解	Medium	归并，快排
278	926. Flip String to Monotone Increasing	Java	题解	Medium
279	931. Minimum Falling Path Sum	Java	题解	Medium
280	946. Validate Stack Sequences	Java	题解	Medium
281	992. Subarrays with K Different Integers	Java	题解	Hard
282	1011. Capacity To Ship Packages Within D Days	Java	题解	Medium
283	1041. Robot Bounded In Circle	Java	题解	Medium
284	1090. Largest Values From Labels	Java	题解	Medium	排序规则跟 179、870 题类似：保存下标，使用其他数组的值对下标数组进行排序。
285	1094. Car Pooling	Java	题解	Medium
286	1109. Corporate Flight Bookings	Java	题解	Medium
287	1110. Delete Nodes And Return Forest	Java	题解	Medium
288	1253. Reconstruct a 2-Row Binary Matrix	Java	题解	Medium
289	1480. Running Sum of 1d Array	Java	题解	Easy
290	1644. Lowest Common Ancestor of a Binary Tree II	Java	题解	Medium	树形DP套路，没有验证答案！
291	1650. Lowest Common Ancestor of a Binary Tree III	Java	题解	Medium	链表相交
292	1823. Find the Winner of the Circular Game	Java	题解	Medium
293	1864. Minimum Number of Swaps to Make the Binary String Alternating	Java	题解	Medium
294	1905. Count Sub Islands	Java	题解	Medium
295	2507. Smallest Value After Replacing With Sum of Prime Factors	Java	题解	Medium

截止目前，一共完成 295 道题。