leetcode练习题

所有题目列表

solution	#	题目	难度	解答	备注
	1	Two Sum	100
	2	Add Two Numbers	80
	3	Longest Substring Without Repeating Characters	-		这个系列的所有题都要多做几遍
	4	Median of Two Sorted Arrays	70		这题很经典，多做几遍
	5	Longest Palindromic Substring	85		这题对比动态规划和最优算法
	6	ZigZag Conversion
	7	Reverse Integer	95
	8	String to Integer (atoi)	90		很考代码能力，容易错
	9	Palindrome Number
通过	10	正则表达式匹配	60	递归法	这题很经典，多做几遍，和#44一起
	11	Container With Most Water
	12	Integer to Roman
	13	Roman to Integer
	14	Longest Common Prefix	双指针
通过	15	3Sum	70
	16	3Sum Closest
通过	17	Letter Combinations of a Phone Number	85	递归/回溯：最后一次递归才加入结果列表
	18	4Sum
两次遍历法待做	19	删除链表的倒数第N个节点	medium	两次遍历法/一次遍历算法	两次遍历法和一次遍历法
	20	有效的括号	100
	21	Merge Two Sorted Lists	90
	22	Generate Parentheses	80		这题看两遍
	23	Merge k Sorted Lists	70
	24	Swap Nodes in Pairs
	25	Reverse Nodes in k-Group	80
	26	Remove Duplicates from Sorted Array	80
	27	Remove Element
	28	Implement strStr()	70
	29	Divide Two Integers
	30	Substring with Concatenation of All Words
	31	Next Permutation
	32	Longest Valid Parentheses
	33	Search in Rotated Sorted Array	80
	34	Search for a Range
	35	Search Insert Position
	36	Valid Sudoku	80
	37	Sudoku Solver	70		这道题是典型的back tracking，多做几遍
	38	Count and Say	80
	39	Combination Sum	70		排列组合系列的题要多做几遍
	40	Combination Sum II	70
	41	First Missing Positive
	42	Trapping Rain Water	95
	43	Multiply Strings	80
	44	Wildcard Matching	60		和#10多做几遍
	45	Jump Game II
	46	Permutations
	47	Permutations II	70		多做几遍
	48	Rotate Image	100
	49	Group Anagrams	95
	50	Pow(x, n)	80
	51	N-Queens
	52	N-Queens II
通过	53	最大子序和	easy	动态规划法	DP算法 : T=O(N),S=O(1).利用nums数组本身作为DP数组
	54	Spiral Matrix	85
	55	Jump Game		贪心法
	56	Merge Intervals	70
	57	Insert Interval	75		这题要多做几遍
	60	Permutation Sequence	70		这题思路巧妙，多做两遍
	61	Rotate List	90
通过	62	不同的路径	medium	排列组合法/DP算法	排列组合法: 将机器人行列要走的轨迹当作要选择的方块
通过	63	不同的路径2	medium	DP算法	DP算法,可以利用原先矩阵将空间复杂度降为 O(1)
	66	Plus One	100		这题多看一遍
	67	Add Binary	100
	68	Text Justification
	69	Sqrt(x)	85
通过	70	爬楼梯	easy	迭代法/动态规划法/递归法
	71	Simplify Path	80
	72	Edit Distance	75
	73	Set Matrix Zeroes	90
	74	Search a 2D Matrix
	75	Sort Colors	65		这题多做几遍，很有意思
	76	Minimum Window Substring	50		这题以及类似的题一定要多做几遍，很经典，参见window
	77	Combinations
	78	Subsets	85
	79	Word Search	85
	80	Remove Duplicates from Sorted Array II	100
	81	Search in Rotated Sorted Array II	70
	82	Remove Duplicates from Sorted List II	75
	83	Remove Duplicates from Sorted List	100
	84	Largest Rectangle in Histogram	70
	85	Maximal Rectangle	75
	86	Partition List	90
	88	Merge Sorted Array	100
	90	Subsets II	80
	91	Decode Ways	75		这题多做几遍，包括#639
	92	Reverse Linked List II	80
	93	Restore IP Addresses	80		多看两遍
	94	Binary Tree Inorder Traversal	100
	95	Unique Binary Search Trees II	70		多做几遍，递归和DP
	96	Unique Binary Search Trees	80
	98	Validate Binary Search Tree	85		注意溢出
	99	Recover Binary Search Tree	60		这题很容易错，要多做几遍
	100	Same Tree	100
	101	对称二叉树	95
	102	Binary Tree Level Order Traversal	85
	103	Binary Tree Zigzag Level Order Traversal	80
	104	二叉树的最大深度	100
	105	Construct Binary Tree from Preorder and Inorder Traversal	95
	106	Construct Binary Tree from Inorder and Postorder Traversal	90
	107	Binary Tree Level Order Traversal II	100
	108	Convert Sorted Array to Binary Search Tree	100
	109	Convert Sorted List to Binary Search Tree	90
	110	平衡二叉树	80
	111	Minimum Depth of Binary Tree	80
	112	Path Sum	85
	113	Path Sum II	65		错了好几次，得多做几遍
	114	Flatten Binary Tree to Linked List	80
	116	Populating Next Right Pointers in Each Node	80
	117	Populating Next Right Pointers in Each Node II	80
	118	Pascal's Triangle	80
	119	Pascal's Triangle II	80
通过	120	三角形最小路径和	medium	基本的dp算法	自上而下，自下而上的方法，可用 dp[][],dp[] 两种辅助空间
	121	Best Time to Buy and Sell Stock	100
	122	Best Time to Buy and Sell Stock II	100
	123	Best Time to Buy and Sell Stock III	75
	124	Binary Tree Maximum Path Sum	60
	125	Valid Palindrome	100
	126	Word Ladder II
	127	Word Ladder	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	60
	129	Sum Root to Leaf Numbers	100
	130	Surrounded Regions	65
	131	Palindrome Partitioning
	132	Palindrome Partitioning II
	133	Clone Graph	70		这题不难，多看两遍，BFS方法再做两遍
	135	Candy	80
	138	Copy List with Random Pointer	95		有一个易错点
	139	Word Break	80		多看两遍
	140	Word Break II	75		这题多做两遍，很典型
	141	Linked List Cycle	75
	142	Linked List Cycle II	90
	143	Reorder List	90
	144	Binary Tree Preorder Traversal	85
	145	Binary Tree Postorder Traversal	80
	146	LRU Cache	95		好题目，多做几遍
	147	Insertion Sort List	90
	148	Sort List	90
	149	Max Points on a Line	60
	150	Evaluate Reverse Polish Notation	70
	151	Reverse Words in a String	70		这题虽然不难，但是也错了几次
	152	Maximum Product Subarray
	153	Find Minimum in Rotated Sorted Array
	154	Find Minimum in Rotated Sorted Array II
	155	Min Stack	95
	156	Binary Tree Upside Down	70		这道题挺有意思，多做几遍
	157	Read N Characters Given Read4	80		这题多做几遍，结合#158
	158	Read N Characters Given Read4 II - Call multiple times	70
	159	Longest Substring with At Most Two Distinct Characters	100		多看两遍
	160	Intersection of Two Linked Lists	100
	161	One Edit Distance	85		和#72做两遍
	162	Find Peak Element	90
	163	Missing Ranges	65		多做几遍，太容易错了
	164	Maximum Gap	65
	167	Two Sum II - Input array is sorted	100
	168	Excel Sheet Column Title
	169	Majority Element	100
	170	Two Sum III - Data structure design	100		这道题再多做一遍
	171	Excel Sheet Column Number
	172	Factorial Trailing Zeroes	100
	173	Binary Search Tree Iterator	70		多留意一下
	179	Largest Number	90
	186	Reverse Words in a String II	90
	188	Best Time to Buy and Sell Stock IV
	189	Rotate Array	100
	190	Reverse Bits	85
	198	打家劫舍	80
	199	Binary Tree Right Side View	80
	200	Number of Islands	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
	204	Count Primes	85
	206	Reverse Linked List	90
	207	Course Schedule	100		典型的拓扑排序
	208	Implement Trie (Prefix Tree)	80		和#211多留意，trie很典型
	209	Minimum Size Subarray Sum	85
	210	Course Schedule II	95
	211	Add and Search Word - Data structure design	85
	212	Word Search II
	213	House Robber II	80
	214	Shortest Palindrome
	215	Kth Largest Element in an Array	65		这题很经典，三种解法都要了然于胸
	216	Combination Sum III	65
	217	Contains Duplicate	100
	218	The Skyline Problem	60		这题多做两遍
	219	Contains Duplicate II	95
	220	Contains Duplicate III	65
	221	Maximal Square	80
	222	Count Complete Tree Nodes	70		一般的做法会超时
	223	Rectangle Area	95
	224	Basic Calculator	80
	225	Implement Stack using Queues	90
	226	Invert Binary Tree	80
	228	Summary Ranges	70
	229	Majority Element II	70
	230	Kth Smallest Element in a BST	85		注意Follow Up
	232	Implement Queue using Stacks	95
	233	Number of Digit One
	234	Palindrome Linked List	75
	235	Lowest Common Ancestor of a Binary Search Tree	100
	236	Lowest Common Ancestor of a Binary Tree	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	100
	238	Product of Array Except Self	85
	239	Sliding Window Maximum	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	100
	241	Different Ways to Add Parentheses
	242	Valid Anagram	100
	243	Shortest Word Distance	80
	244	Shortest Word Distance II	80
	245	Shortest Word Distance III	80
	246	Strobogrammatic Number	70		#247一个系列，多看两遍
	247	Strobogrammatic Number II	70		多看两遍
	249	Group Shifted Strings
	250	Count Univalue Subtrees	70		这题要多做几遍
	251	Flatten 2D Vector	100
	252	Meeting Rooms	100
	253	Meeting Rooms II	90
	254	Factor Combinations	80
	255	Verify Preorder Sequence in Binary Search Tree	85		很简单，粗心错了
	256	Paint House	95
	257	Binary Tree Paths	80
	259	3Sum Smaller	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	70		这题多做几遍
	263	Ugly Number	85
	264	Ugly Number II	70
	265	Paint House II	60
	266	Palindrome Permutation	100
	267	Palindrome Permutation II	80		典型，多看两遍
	268	Missing Number	100
	269	Alien Dictionary	70		这题要多做几遍
	270	Closest Binary Search Tree Value	90
	271	Encode and Decode Strings	65		思路巧妙，多看几遍
	272	Closest Binary Search Tree Value II	60		这题非常值得多做几遍，几种写法都试试
	273	Integer to English Words	75		多做几遍，做到bug free
	274	H-Index	80
	275	H-Index II	75
	277	Find the Celebrity	100
	278	First Bad Version	100
	279	Perfect Squares	95
	280	Wiggle Sort	80		思路巧妙，多看两遍
	281	Zigzag Iterator	85		多做三遍，考虑扩展到k的情况
	282	Expression Add Operators	50
	283	Move Zeroes	100
	284	Peeking Iterator	100
	285	Inorder Successor in BST	70		这道题有意思，要多做几遍
	286	Walls and Gates	70		多看两遍
	287	Find the Duplicate Number
	288	Unique Word Abbreviation	70		这题不难，多做两遍，题目意思容易理解错
	289	Game of Life	70
	293	Flip Game	90
	294	Flip Game II	90
	295	Find Median from Data Stream
	297	Serialize and Deserialize Binary Tree	80		好题目，多做做，递归的非递归的
	298	Binary Tree Longest Consecutive Sequence	70		多做三遍，尽可能简洁
	299	猜数字游戏			两次遍历，一次遍历
	300	Longest Increasing Subsequence
	301	Remove Invalid Parentheses	70		比较难，多做几遍
	302	Smallest Rectangle Enclosing Black Pixels
	303	Range Sum Query - Immutable	100
	304	Range Sum Query 2D - Immutable	65
	305	Number of Islands II	70		这题多做几遍，经典的UF
	307	Range Sum Query - Mutable	70		和#303, #304, #308定要多做几遍，掌握BIT
	308	Range Sum Query 2D - Mutable	70
	309	Best Time to Buy and Sell Stock with Cooldown
	310	Minimum Height Trees	60		这题多做几遍
	311	Sparse Matrix Multiplication	80
	312	Burst Balloons	60
	313	Super Ugly Number
	314	Binary Tree Vertical Order Traversal	80
	315	Count of Smaller Numbers After Self	60
	316	去除重复字母	70
	317	Shortest Distance from All Buildings	75		典型的bfs，多做两遍
	319	Bulb Switcher	90
	320	Generalized Abbreviation	70		这题是典型的back tracking，多做几遍
	322	Coin Change	80
	323	Number of Connected Components in an Undirected Graph	90		典型的图，多看两遍
	324	Wiggle Sort II	60
	325	Maximum Size Subarray Sum Equals k	75		这题思路有意思，多做几遍
	328	Odd Even Linked List	90
	329	Longest Increasing Path in a Matrix	70		这题要多做几遍
	332	Reconstruct Itinerary
	333	Largest BST Subtree	50		这道题虽然不难，但是折腾了很久，一定要多做
	334	Increasing Triplet Subsequence	75
	335	Self Crossing	80
	336	Palindrome Pairs
	337	House Robber III	70		建议再做两遍
	339	Nested List Weight Sum
	340	Longest Substring with At Most K Distinct Characters	80		和#159类似
	341	Flatten Nested List Iterator	75		这题有点意思，多做两遍
	344	Reverse String	100
	345	Reverse Vowels of a String	100
	346	Moving Average from Data Stream	95
	347	Top K Frequent Elements	85
	349	Intersection of Two Arrays
	350	Intersection of Two Arrays II
	351	Android Unlock Patterns	70		这题多做几遍
	357	Count Numbers with Unique Digits
	358	Rearrange String k Distance Apart
	359	Logger Rate Limiter	100		这题如果不考虑空间消耗的话其实很简单
	361	Bomb Enemy	65		这题多做几遍，开始没思路
	364	Nested List Weight Sum II
	366	Find Leaves of Binary Tree	60		这道题刚开始还没思路
	367	Valid Perfect Square
	369	Plus One Linked List	100
	370	Range Addition	80
	373	Find K Pairs with Smallest Sums
	374	Guess Number Higher or Lower	100
	375	Guess Number Higher or Lower II	60
	377	Combination Sum IV	65
	378	Kth Smallest Element in a Sorted Matrix
	380	Insert Delete GetRandom O(1)	75		这道题很有意思，多做几遍
	381	Insert Delete GetRandom O(1) - Duplicates allowed
	382	Linked List Random Node
	384	Shuffle an Array	75
	387	First Unique Character in a String	100
	388	Longest Absolute File Path	65		其实不难，乍看没思路，多做几遍
	391	Perfect Rectangle	70		这题很trick，多做两遍
通过	392	判断子序列	esay	贪心算法/DP算法	DP算法：不建议使用，纯粹学习思想
	393	UTF-8 Validation	60		错了很多次，多做几遍
	394	Decode String	75		这题容易错，多做四遍
	395	Longest Substring with At Least K Repeating Characters	65
	398	Random Pick Index	80
	399	Evaluate Division	60		这题多做几遍
	401	Binary Watch
	404	Sum of Left Leaves	80
	406	根据身高重建队列	60		这题开始没思路，多做几遍
	407	Trapping Rain Water II
	408	Valid Word Abbreviation	80		多做两遍
	409	Longest Palindrome
	410	Split Array Largest Sum
	412	Fizz Buzz	100
	413	Third Maximum Number	80
	418	Sentence Screen Fitting	65		这题思路巧妙，多做几遍，常规思路超时
	422	Valid Word Square	90
	425	Word Squares	70		这题很典型，多做几遍
	436	Find Right Interval
	437	Path Sum III	60		这道题错了很多遍，要重点关注
	438	Find All Anagrams in a String	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	80
	445	Add Two Numbers II	80
	448	Find All Numbers Disappeared in an Array	80
	449	Serialize and Deserialize BST	90		和#297一样
通过	450	Delete Node in a BST	60		这题非常经典，值得多做十遍
	451	Sort Characters By Frequency
通过	455	分发饼干	esay	贪心算法	贪心算法
	458	可怜的小猪	Hard
	459	Repeated Substring Pattern
	477	Total Hamming Distance
	480	Sliding Window Median	70
	482	License Key Formatting	90
	483	Smallest Good Base
	485	Max Consecutive Ones	100
	487	Max Consecutive Ones II	80
	501	Find Mode in Binary Search Tree	70		不难，容易错，多做两次
	508	Most Frequent Subtree Sum
	513	Find Bottom Left Tree Value	100
	515	Find Largest Value in Each Tree Row	100
	524	Longest Word in Dictionary through Deleting
	526	Beautiful Arrangement	80
	535	Encode and Decode TinyURL	100
	538	Convert BST to Greater Tree	100
	541	Reverse String II	100
	543	Diameter of Binary Tree	80		这题易错
	547	Friend Circles	70
	557	Reverse Words in a String III	100
	560	Subarray Sum Equals K	70
	563	Binary Tree Tilt	90
	564	Find the Closest Palindrome	80		此题暴力法即可
	572	Subtree of Another Tree	80
	606	Construct String from Binary Tree	90
	617	Merge Two Binary Trees	100		很简单
	621	Task Scheduler	70
	637	Average of Levels in Binary Tree	100
	652	Find Duplicate Subtrees	70		开始还没思路
	653	Two Sum IV - Input is a BST	90
	654	Maximum Binary Tree	100
	669	Trim a Binary Search Tree	100
	681	Next Closest Time	80		这题多做几遍
	683	K Empty Slots	80
	684	Redundant Connection
	687	Longest Univalue Path	70
	695	Max Area of Island	100
小根堆解法待做	703	数据流中第K大元素	medium	优先级队列解法/小根堆解法	优先级队列解法/小根堆解法
	771	Jewels and Stones	100
	814	Binary Tree Pruning	80
	819	Most Common Word	85
	843	Guess the Word	90
	844	Backspace String Compare	100
	849	Maximize Distance to Closest Person	80
	857	Minimum Cost to Hire K Workers	70
	871	最低加油次数	80
	872	Leaf-Similar Trees	80
	889	Construct Binary Tree from Preorder and Postorder Traversal	80
	904	Fruit Into Baskets	90
	929	Unique Email Addresses	90

四方云和 / JavaPrinciple

leetcode练习题

所有题目列表

简介

发行版

贡献者

近期动态

四方云和 / JavaPrinciple .gitee-modal { width: 500px !important; }

leetcode练习题

所有题目列表

简介

发行版

贡献者

近期动态

搜索帮助

四方云和 / JavaPrinciple