Leetcode - Java

一、电子书(pdf)

Latex排版整理的电子书

• Backtracking
• Graph
• Tree
• DP
• Array
• List

二、文档列表

• 刷题要点总结
• Facebook面试总结
• Bitset技巧
• Map新接口

三、所有题目列表

#	Title	Solution	Score	Backup
1	Two Sum	Java	100
2	Add Two Numbers	Java	80
3	Longest Substring Without Repeating Characters	Java		这个系列的所有题都要多做几遍
4	Median of Two Sorted Arrays	Java	70	这题很经典，多做几遍
5	Longest Palindromic Substring	Java	85	这题对比动态规划和最优算法
6	ZigZag Conversion	Java
7	Reverse Integer	Java	95
8	String to Integer (atoi)	Java	90	很考代码能力，容易错
9	Palindrome Number	Java
10	Regular Expression Matching	Java	60	这题很经典，多做几遍，和#44一起
11	Container With Most Water	Java
12	Integer to Roman	Java
13	Roman to Integer	Java
14	Longest Common Prefix	Java
15	3Sum	Java	70
16	3Sum Closest	Java
17	Letter Combinations of a Phone Number	Java	85
18	4Sum	Java
19	Remove Nth Node From End of List	Java
20	Valid Parentheses	Java	100
21	Merge Two Sorted Lists	Java	90
22	Generate Parentheses	Java	80	这题看两遍
23	Merge k Sorted Lists	Java	70
24	Swap Nodes in Pairs	Java
25	Reverse Nodes in k-Group	Java	80
26	Remove Duplicates from Sorted Array	Java	80
27	Remove Element	Java
28	Implement strStr()	Java	70
29	Divide Two Integers	Java
30	Substring with Concatenation of All Words	Java
31	Next Permutation	Java
32	Longest Valid Parentheses	Java
33	Search in Rotated Sorted Array	Java	80
34	Search for a Range	Java
35	Search Insert Position	Java
36	Valid Sudoku	Java	80
37	Sudoku Solver	Java	70	这道题是典型的back tracking，多做几遍
38	Count and Say	Java	80
39	Combination Sum	Java	70	排列组合系列的题要多做几遍
40	Combination Sum II	Java	70
41	First Missing Positive	Java
42	Trapping Rain Water	Java	95
43	Multiply Strings	Java	80
44	Wildcard Matching	Java	60	和#10多做几遍
45	Jump Game II	Java
46	Permutations	Java
47	Permutations II	Java	70	多做几遍
48	Rotate Image	Java	100
49	Group Anagrams	Java	95
50	Pow(x, n)	Java	80
51	N-Queens	Java
52	N-Queens II	Java
53	Maximum Subarray	Java	95
54	Spiral Matrix	Java	85
55	Jump Game	Java
56	Merge Intervals	Java	70
57	Insert Interval	Java	75	这题要多做几遍
60	Permutation Sequence	Java	70	这题思路巧妙，多做两遍
61	Rotate List	Java	90
66	Plus One	Java	100	这题多看一遍
67	Add Binary	Java	100
68	Text Justification	Java
69	Sqrt(x)	Java	85
71	Simplify Path	Java	80
72	Edit Distance	Java	75
73	Set Matrix Zeroes	Java	90
74	Search a 2D Matrix	Java
75	Sort Colors	Java	65	这题多做几遍，很有意思
76	Minimum Window Substring	Java	50	这题以及类似的题一定要多做几遍，很经典，参见window
77	Combinations	Java
78	Subsets	Java	85
79	Word Search	Java	85
80	Remove Duplicates from Sorted Array II	Java	100
81	Search in Rotated Sorted Array II	Java	70
82	Remove Duplicates from Sorted List II	Java	75
83	Remove Duplicates from Sorted List	Java	100
84	Largest Rectangle in Histogram	Java	70
85	Maximal Rectangle	Java	75
86	Partition List	Java	90
88	Merge Sorted Array	Java	100
90	Subsets II	Java	80
91	Decode Ways	Java	75	这题多做几遍，包括#639
92	Reverse Linked List II	Java	80
93	Restore IP Addresses	Java	80	多看两遍
94	Binary Tree Inorder Traversal	Java	100
95	Unique Binary Search Trees II	Java	70	多做几遍，递归和DP
96	Unique Binary Search Trees	Java	80
98	Validate Binary Search Tree	Java	85	注意溢出
99	Recover Binary Search Tree	Java	60	这题很容易错，要多做几遍
100	Same Tree	Java	100
101	Symmetric Tree	Java	95
102	Binary Tree Level Order Traversal	Java	85
103	Binary Tree Zigzag Level Order Traversal	Java	80
104	Maximum Depth of Binary Tree	Java	100
105	Construct Binary Tree from Preorder and Inorder Traversal	Java	95
106	Construct Binary Tree from Inorder and Postorder Traversal	Java	90
107	Binary Tree Level Order Traversal II	Java	100
108	Convert Sorted Array to Binary Search Tree	Java	100
109	Convert Sorted List to Binary Search Tree	Java	90
110	Balanced Binary Tree	Java	80
111	Minimum Depth of Binary Tree	Java	80
112	Path Sum	Java	85
113	Path Sum II	Java	65	错了好几次，得多做几遍
114	Flatten Binary Tree to Linked List	Java	80
116	Populating Next Right Pointers in Each Node	Java	80
117	Populating Next Right Pointers in Each Node II	Java	80
118	Pascal's Triangle	Java	80
119	Pascal's Triangle II	Java	80
121	Best Time to Buy and Sell Stock	Java	100
122	Best Time to Buy and Sell Stock II	Java	100
123	Best Time to Buy and Sell Stock III	Java	75
124	Binary Tree Maximum Path Sum	Java	60
125	Valid Palindrome	Java	100
126	Word Ladder II	Java
127	Word Ladder	Java	70	此题非常经典，务必连同ii多做几遍，将双端BFS吃透
128	Longest Consecutive Sequence	Java	60
129	Sum Root to Leaf Numbers	Java	60	这题错了几次，多做几遍
130	Surrounded Regions	Java	65
131	Palindrome Partitioning	Java
132	Palindrome Partitioning II	Java
133	Clone Graph	Java	70	这题不难，多看两遍，BFS方法再做两遍
138	Copy List with Random Pointer	Java	95	有一个易错点
139	Word Break	Java	80	多看两遍
140	Word Break II	Java	75	这题多做两遍，很典型
141	Linked List Cycle	Java	75
142	Linked List Cycle II	Java	90
143	Reorder List	Java	90
144	Binary Tree Preorder Traversal	Java	85
145	Binary Tree Postorder Traversal	Java	80
146	LRU Cache	Java	95	好题目，多做几遍
147	Insertion Sort List	Java	90
148	Sort List	Java	90
149	Max Points on a Line	Java	60
150	Evaluate Reverse Polish Notation	Java	70
151	Reverse Words in a String	Java	70	这题虽然不难，但是也错了几次
152	Maximum Product Subarray	Java
153	Find Minimum in Rotated Sorted Array	Java
154	Find Minimum in Rotated Sorted Array II	Java
155	Min Stack	Java	95
156	Binary Tree Upside Down	Java	70	这道题挺有意思，多做几遍
157	Read N Characters Given Read4	Java	80	这题多做几遍，结合#158
158	Read N Characters Given Read4 II - Call multiple times	Java	70
159	Longest Substring with At Most Two Distinct Characters	Java	100	多看两遍
160	Intersection of Two Linked Lists	Java	100
161	One Edit Distance	Java	85	和#72做两遍
162	Find Peak Element	Java	90
163	Missing Ranges	Java	65	多做几遍，太容易错了
164	Maximum Gap	Java	65
167	Two Sum II - Input array is sorted	Java	100
168	Excel Sheet Column Title	Java
169	Majority Element	Java	100
170	Two Sum III - Data structure design	Java	100	这道题再多做一遍
171	Excel Sheet Column Number	Java
172	Factorial Trailing Zeroes	Java	100
173	Binary Search Tree Iterator	Java	70	多留意一下
179	Largest Number	Java	90
186	Reverse Words in a String II	Java	90
188	Best Time to Buy and Sell Stock IV	Java
189	Rotate Array	Java	100
190	Reverse Bits	Java	85
198	House Robber	Java	80
199	Binary Tree Right Side View	Java	80
200	Number of Islands	Java	85	这道题很经典，而且方法不止一种，每种方法都多做几遍，包括UF，#305
203	Remove Linked List Elements	Java
204	Count Primes	Java	85
206	Reverse Linked List	Java	90
207	Course Schedule	Java	100	典型的拓扑排序
208	Implement Trie (Prefix Tree)	Java	80	和#211多留意，trie很典型
209	Minimum Size Subarray Sum	Java	85
210	Course Schedule II	Java	95
211	Add and Search Word - Data structure design	Java	85
212	Word Search II	Java
213	House Robber II	Java	80
214	Shortest Palindrome	Java
215	Kth Largest Element in an Array	Java	65	这题很经典，三种解法都要了然于胸
216	Combination Sum III	Java	65
217	Contains Duplicate	Java	100
218	The Skyline Problem	Java	60	这题多做两遍
219	Contains Duplicate II	Java	95
220	Contains Duplicate III	Java	65
221	Maximal Square	Java	80
222	Count Complete Tree Nodes	Java	70	一般的做法会超时
223	Rectangle Area	Java	95
224	Basic Calculator	Java	80
225	Implement Stack using Queues	Java	90
226	Invert Binary Tree	Java	80
228	Summary Ranges	Java	70
229	Majority Element II	Java	70
230	Kth Smallest Element in a BST	Java	85	注意Follow Up
232	Implement Queue using Stacks	Java	95
233	Number of Digit One	Java
234	Palindrome Linked List	Java	75
235	Lowest Common Ancestor of a Binary Search Tree	Java	100
236	Lowest Common Ancestor of a Binary Tree	Java	50	这题很经典，多做几遍，留意节点不在树中的情况
237	Delete Node in a Linked List	Java	100
238	Product of Array Except Self	Java	85
239	Sliding Window Maximum	Java	75	这题非常经典，多做几遍，包括常规算法(优先队列，treemap)及优化算法双端队列
240	Search a 2D Matrix II	Java	100
241	Different Ways to Add Parentheses	Java
242	Valid Anagram	Java	100
243	Shortest Word Distance	Java	80
244	Shortest Word Distance II	Java	80
245	Shortest Word Distance III	Java	80
246	Strobogrammatic Number	Java	70	#247一个系列，多看两遍
247	Strobogrammatic Number II	Java	70	多看两遍
249	Group Shifted Strings	Java
250	Count Univalue Subtrees	Java	70	这题要多做几遍
251	Flatten 2D Vector	Java	100
252	Meeting Rooms	Java	100
253	Meeting Rooms II	Java	90
254	Factor Combinations	Java	80
255	Verify Preorder Sequence in Binary Search Tree	Java	85	很简单，粗心错了
256	Paint House	Java	95
257	Binary Tree Paths	Java	80
259	3Sum Smaller	Java	95	这题虽然简单，但是因为思维定式还是错了几次
261	Graph Valid Tree	Java	70	这题多做几遍
263	Ugly Number	Java	85
264	Ugly Number II	Java	70
265	Paint House II	Java	60
266	Palindrome Permutation	Java	100
267	Palindrome Permutation II	Java	80	典型，多看两遍
268	Missing Number	Java	100
269	Alien Dictionary	Java	70	这题要多做几遍
270	Closest Binary Search Tree Value	Java	90
271	Encode and Decode Strings	Java	65	思路巧妙，多看几遍
272	Closest Binary Search Tree Value II	Java	60	这题非常值得多做几遍，几种写法都试试
273	Integer to English Words	Java	75	多做几遍，做到bug free
274	H-Index	Java	80
275	H-Index II	Java	75
277	Find the Celebrity	Java	100
278	First Bad Version	Java	100
279	Perfect Squares	Java	95
280	Wiggle Sort	Java	80	思路巧妙，多看两遍
281	Zigzag Iterator	Java	85	多做三遍，考虑扩展到k的情况
282	Expression Add Operators	Java	50
283	Move Zeroes	Java	100
284	Peeking Iterator	Java	100
285	Inorder Successor in BST	Java	70	这道题有意思，要多做几遍
286	Walls and Gates	Java	70	多看两遍
287	Find the Duplicate Number	Java
288	Unique Word Abbreviation	Java	70	这题不难，多做两遍，题目意思容易理解错
289	Game of Life	Java	70
293	Flip Game	Java	90
294	Flip Game II	Java	90
295	Find Median from Data Stream	Java
297	Serialize and Deserialize Binary Tree	Java	80	好题目，多做做，递归的非递归的
298	Binary Tree Longest Consecutive Sequence	Java	70	多做三遍，尽可能简洁
300	Longest Increasing Subsequence	Java
301	Remove Invalid Parentheses	Java	70	比较难，多做几遍
302	Smallest Rectangle Enclosing Black Pixels	Java
303	Range Sum Query - Immutable	Java	100
304	Range Sum Query 2D - Immutable	Java	65
305	Number of Islands II	Java	70	这题多做几遍，经典的UF
307	Range Sum Query - Mutable	Java	70	和#303, #304, #308定要多做几遍，掌握BIT
308	Range Sum Query 2D - Mutable	Java	70
309	Best Time to Buy and Sell Stock with Cooldown	Java
310	Minimum Height Trees	Java	60	这题多做几遍
311	Sparse Matrix Multiplication	Java	80
312	Burst Balloons	Java	60
313	Super Ugly Number	Java
314	Binary Tree Vertical Order Traversal	Java	80
315	Count of Smaller Numbers After Self	Java	60
316	Remove Duplicate Letters	Java	70
317	Shortest Distance from All Buildings	Java	75	典型的bfs，多做两遍
319	Bulb Switcher	Java	90
320	Generalized Abbreviation	Java	70	这题是典型的back tracking，多做几遍
323	Number of Connected Components in an Undirected Graph	Java	90	典型的图，多看两遍
324	Wiggle Sort II	Java	60
325	Maximum Size Subarray Sum Equals k	Java	75	这题思路有意思，多做几遍
328	Odd Even Linked List	Java	90
329	Longest Increasing Path in a Matrix	Java	70	这题要多做几遍
332	Reconstruct Itinerary	Java
333	Largest BST Subtree	Java	50	这道题虽然不难，但是折腾了很久，一定要多做
334	Increasing Triplet Subsequence	Java	75
335	Self Crossing	Java	80
336	Palindrome Pairs	Java
337	House Robber III	Java	70	建议再做两遍
339	Nested List Weight Sum	Java
340	Longest Substring with At Most K Distinct Characters	Java	80	和#159类似
341	Flatten Nested List Iterator	Java	75	这题有点意思，多做两遍
344	Reverse String	Java	100
345	Reverse Vowels of a String	Java	100
346	Moving Average from Data Stream	Java	95
347	Top K Frequent Elements	Java	85
349	Intersection of Two Arrays	Java
350	Intersection of Two Arrays II	Java
351	Android Unlock Patterns	Java	70	这题多做几遍
357	Count Numbers with Unique Digits	Java
358	Rearrange String k Distance Apart	Java
359	Logger Rate Limiter	Java	100	这题如果不考虑空间消耗的话其实很简单
361	Bomb Enemy	Java	65	这题多做几遍，开始没思路
364	Nested List Weight Sum II	Java
366	Find Leaves of Binary Tree	Java	60	这道题刚开始还没思路
367	Valid Perfect Square	Java
369	Plus One Linked List	Java	100
370	Range Addition	Java	80
373	Find K Pairs with Smallest Sums	Java
374	Guess Number Higher or Lower	Java	100
375	Guess Number Higher or Lower II	Java	60
377	Combination Sum IV	Java	65
378	Kth Smallest Element in a Sorted Matrix	Java
380	Insert Delete GetRandom O(1)	Java	75	这道题很有意思，多做几遍
381	Insert Delete GetRandom O(1) - Duplicates allowed	Java
382	Linked List Random Node	Java
384	Shuffle an Array	Java	75
387	First Unique Character in a String	Java	100
388	Longest Absolute File Path	Java	65	其实不难，乍看没思路，多做几遍
391	Perfect Rectangle	Java	70	这题很trick，多做两遍
393	UTF-8 Validation	Java	60	错了很多次，多做几遍
394	Decode String	Java	75	这题容易错，多做四遍
395	Longest Substring with At Least K Repeating Characters	Java	65
398	Random Pick Index	Java	80
399	Evaluate Division	Java	60	这题多做几遍
401	Binary Watch	Java
404	Sum of Left Leaves	Java	80
406	Queue Reconstruction by Height	Java	60	这题开始没思路，多做几遍
407	Trapping Rain Water II	Java
408	Valid Word Abbreviation	Java	80	多做两遍
409	Longest Palindrome	Java
410	Split Array Largest Sum	Java
412	Fizz Buzz	Java	100
413	Third Maximum Number	Java	80
418	Sentence Screen Fitting	Java	65	这题思路巧妙，多做几遍，常规思路超时
422	Valid Word Square	Java	90
425	Word Squares	Java	70	这题很典型，多做几遍
436	Find Right Interval	Java
437	Path Sum III	Java	60	这道题错了很多遍，要重点关注
438	Find All Anagrams in a String	Java	75	这道题非常经典，最优解法需要多做几遍，保证once bug free
442	Find All Duplicates in an Array	Java	80
445	Add Two Numbers II	Java	80
448	Find All Numbers Disappeared in an Array	Java	80
449	Serialize and Deserialize BST	Java	90	和#297一样
450	Delete Node in a BST	Java	60	这题非常经典，值得多做十遍
451	Sort Characters By Frequency	Java
459	Repeated Substring Pattern	Java
477	Total Hamming Distance	Java
480	Sliding Window Median	Java	70
482	License Key Formatting	Java	90
483	Smallest Good Base	Java
485	Max Consecutive Ones	Java	100
487	Max Consecutive Ones II	Java	80
501	Find Mode in Binary Search Tree	Java	70	不难，容易错，多做两次
508	Most Frequent Subtree Sum	Java
513	Find Bottom Left Tree Value	Java	100
515	Find Largest Value in Each Tree Row	Java	100
524	Longest Word in Dictionary through Deleting	Java
526	Beautiful Arrangement	Java	80
535	Encode and Decode TinyURL	Java	100
541	Reverse String II	Java	100
557	Reverse Words in a String III	Java	100
560	Subarray Sum Equals K	Java	70
617	Merge Two Binary Trees	Java	100	很简单
637	Average of Levels in Binary Tree	Java	100
652	Find Duplicate Subtrees	Java	70	开始还没思路
653	Two Sum IV - Input is a BST	Java	90
669	Trim a Binary Search Tree	Java	100
684	Redundant Connection	Java