leetcode面试频率及总结

	1	Two Sum	2	5	array	sort
					set	Two Pointers
	2	Add Two Numbers	3	4	linked list	Two Pointers
						Math
	3	Longest Substring Without Repeating Characters	3	2	string	Two Pointers
					hashtable
	4	Median of Two Sorted Arrays	5	3	array	Binary Search
	5	Longest Palindromic Substring	4	2	string
	6	ZigZag Conversion	3	1	string
	7	Reverse Integer	2	3		Math
	8	String to Integer (atoi)	2	5	string	Math
	9	Palindrome Number	2	2		Math
	10	Regular Expression Matching	5	3	string	Recursion
						DP
	11	Container With Most Water	3	2	array	Two Pointers
	12	Integer to Roman	3	4		Math
	13	Roman to Integer	2	4		Math
	14	Longest Common Prefix	2	1	string
	15	3Sum	3	5	array	Two Pointers
	16	3Sum Closest	3	1	array	Two Pointers
	17	Letter Combinations of a Phone Number	3	3	string	DFS
	18	4Sum	3	2	array
	19	Remove Nth Node From End of List	2	3	linked list	Two Pointers
	20	Valid Parentheses	2	5	string	Stack
	21	Merge Two Sorted Lists	2	5	linked list	sort
						Two Pointers
						merge
	22	Generate Parentheses	3	4	string	DFS
	23	Merge k Sorted Lists	3	4	linked list	sort
					heap	Two Pointers
						merge
	24	Swap Nodes in Pairs	2	4	linked list
	25	Reverse Nodes in k-Group	4	2	linked list	Recursion
						Two Pointers
	26	Remove Duplicates from Sorted Array	1	3	array	Two Pointers
	27	Remove Element	1	4	array	Two Pointers
	28	Implement strStr()	4	5	string	Two Pointers
						KMP
						rolling hash
	29	Divide Two Integers	4	3		Binary Search
						Math
	30	Substring with Concatenation of All Words	3	1	string	Two Pointers
	31	Next Permutation	5	2	array	permutation
	32	Longest Valid Parentheses	4	1	string	DP
	33	Search in Rotated Sorted Array	4	3	array	Binary Search
	34	Search for a Range	4	3	array	Binary Search
	35	Search Insert Position	2	2	array
	36	Valid Sudoku	2	2	array
	37	Sudoku Solver	4	2	array	DFS
	38	Count and Say	2	2	string	Two Pointers
	39	Combination Sum	3	3	array	combination
	40	Combination Sum II	4	2	array	combination
	41	First Missing Positive	5	2	array	sort
	42	Trapping Rain Water	4	2	array	Two Pointers
						Stack
	43	Multiply Strings	4	3	string	Two Pointers
						Math
	44	Wildcard Matching	5	3	string	Recursion
						DP
						greedy
	45	Jump Game II	4	2	array
	46	Permutations	3	4	array	permutation
	47	Permutations II	4	2	array	permutation
	48	Rotate Image	4	2	array
	49	Anagrams	3	4	string
					hashtable
	50	Pow(x, n)	3	5		Binary Search
						Math
	51	N-Queens	4	3	array	DFS
	52	N-Queens II	4	3	array	DFS
	53	Maximum Subarray	3	3	array	DP
	54	Spiral Matrix	4	2	array
	55	Jump Game	3	2	array
	56	Merge Intervals	4	5	array	sort
					linked list	merge
					red-black tree
	57	Insert Interval	4	5	array	sort
					linked list	merge
					red-black tree
	58	Length of Last Word	1	1	string
	59	Spiral Matrix II	3	2	array
	60	Permutation Sequence	5	1		permutation
						Math
	61	Rotate List	3	2	linked list	Two Pointers
	62	Unique Paths	2	3	array	DP
	63	Unique Paths II	3	3	array	DP
	64	Minimum Path Sum	3	3	array	DP
	65	Valid Number	2	5	string	Math
	66	Plus One	1	2	array	Math
	67	Add Binary	2	4	string	Two Pointers
						Math
	68	Text Justification	4	2	string
	69	Sqrt(x)	4	4		Binary Search
	70	Climbing Stairs	2	5		DP
	71	Simplify Path	3	1	string	Stack
	72	Edit Distance	4	3	string	DP
	73	Set Matrix Zeroes	3	5	array
	74	Search a 2D Matrix	3	3	array	Binary Search
	75	Sort Colors	4	2	array	sort
						Two Pointers
	76	Minimum Window Substring	4	2	string	Two Pointers
	77	Combinations	3	4		combination
	78	Subsets	3	4	array	Recursion
						combination
	79	Word Search	3	4	array	DFS
	80	Remove Duplicates from Sorted Array II	2	2	array	Two Pointers
	81	Search in Rotated Sorted Array II	5	3	array	Binary Search
	82	Remove Duplicates from Sorted List II	3	3	linked list	Recursion
						Two Pointers
	83	Remove Duplicates from Sorted List	1	3	linked list
	84	Largest Rectangle in Histogram	5	2	array	Stack
	85	Maximal Rectangle	5	1	array	DP
						Stack
	86	Partition List	3	3	linked list	Two Pointers
	87	Scramble String	5	2	string	Recursion
						DP
	88	Merge Sorted Array	2	5	array	Two Pointers
						merge
	89	Gray Code	4	2		combination
	90	Subsets II	4	2	array	Recursion
						combination
	91	Decode Ways	3	4	string	Recursion
						DP
	92	Reverse Linked List II	3	2	linked list	Two Pointers
	93	Restore IP Addresses	3	3	string	DFS
	94	Binary Tree Inorder Traversal	4	3	tree	Recursion
					hashtable	morris
						Stack
	95	Unique Binary Search Trees II	4	1	tree	DP
						DFS
	96	Unique Binary Search Trees	3	1	tree	DP
	97	Interleaving String	5	2	string	Recursion
						DP
	98	Validate Binary Search Tree	3	5	tree	DFS
	99	Recover Binary Search Tree	4	2	tree	DFS
	100	Same Tree	1	1	tree	DFS
	101	Symmetric Tree	1	2	tree	DFS
	102	Binary Tree Level Order Traversal	3	4	tree	BFS
	103	Binary Tree Zigzag Level Order Traversal	4	3	queue	BFS
					tree	Stack
	104	Maximum Depth of Binary Tree	1	1	tree	DFS
	105	Construct Binary Tree from Preorder and Inorder Tr	3	3	array	DFS
					tree
	106	Construct Binary Tree from Inorder and Postorder T	3	3	array	DFS
					tree
	107	Binary Tree Level Order Traversal II	3	1	tree	BFS
	108	Convert Sorted Array to Binary Search Tree	2	3	tree	DFS
	109	Convert Sorted List to Binary Search Tree	4	3	linked list	Recursion
						Two Pointers
	110	Balanced Binary Tree	1	2	tree	DFS
	111	Minimum Depth of Binary Tree	1	1	tree	DFS
	112	Path Sum	1	3	tree	DFS
	113	Path Sum II	2	2	tree	DFS
	114	Flatten Binary Tree to Linked List	3	3	tree	Recursion
						Stack
	115	Distinct Subsequences	4	2	string	DP
	116	Populating Next Right Pointers in Each Node	3	3	tree	DFS
	117	Populating Next Right Pointers in Each Node II	4	2	tree	DFS
	118	Pascal's Triangle	2	1	array
	119	Pascal's Triangle II	2	1	array
	120	Triangle	3	1	array	DP
	121	Best Time to Buy and Sell Stock	2	1	array	DP
	122	Best Time to Buy and Sell Stock II	3	1	array	greedy
	123	Best Time to Buy and Sell Stock III	4	1	array	DP
	124	Binary Tree Maximum Path Sum	4	2	tree	DFS
	125	Valid Palindrome	2	5	string	Two Pointers
	126	Word Ladder II	1	1
	127	Word Ladder	3	5	graph	BFS
						shortest path
	128	Longest Consecutive Sequence	4	3	array
	129	Sum Root to Leaf Numbers	2	4	tree	DFS
	130	Surrounded Regions	4	3	array	BFS
						DFS
	131	Palindrome Partitioning	3	4	string	DFS
	132	Palindrome Partitioning II	4	3	string	DP

思路方法总结：

题目	算法	数据结构	注意事项
Clone Graph	BFS	哈希表
Word Ladder II	BFS	哈希表
Surrounded Regions	BFS	矩阵
Word Ladder	BFS	N/A
Binary Tree Level Order Traversal	BFS|前序遍历	队列
Binary Tree Level Order Traversal II	BFS|前序遍历	队列
Binary Tree Zigzag Level Order Traversal	BFS|前序遍历	队列	每一层顺序分别对待
Implement strStr()	KMP算法	N/A
Copy List with Random Pointer	N/A	哈希表
Remove Duplicates from Sorted Array	N/A	哈希表
Remove Duplicates from Sorted Array II	N/A	哈希表
Set Matrix Zeroes	N/A	哈希表
Anagrams	N/A	哈希表
First Missing Positive	N/A	哈希表
Two Sum	N/A	哈希表
Evaluate Reverse Polish Notation	N/A	堆栈
Largest Rectangle in Histogram	N/A	堆栈	记录重要位置
Minimum Window Substring	N/A	堆栈
Simplify Path	N/A	堆栈
Longest Valid Parentheses	N/A	堆栈
Valid Parentheses	N/A	堆栈	词法分析
Container With Most Water	N/A	堆栈	记录重要位置
Reverse Words in a String	N/A	堆栈	翻转字符串
Best Time to Buy and Sell Stock	N/A	数组
Best Time to Buy and Sell Stock II	N/A	数组
Best Time to Buy and Sell Stock III	N/A	数组
Length of Last Word	N/A	数组
Search Insert Position	N/A	数组
Search for a Range	N/A	数组
Spiral Matrix	N/A	矩阵	简化为子问题
Spiral Matrix II	N/A	矩阵	简化为子问题
LRU Cache	N/A	链表
Reorder List	N/A	链表	快慢指针&链表倒序
Linked List Cycle	N/A	链表	快慢指针
Linked List Cycle II	N/A	链表	快慢指针
Reverse Linked List II	N/A	链表
Partition List	N/A	链表
Remove Duplicates from Sorted List	N/A	链表
Remove Duplicates from Sorted List II	N/A	链表
Merge Two Sorted Lists	N/A	链表
Rotate List	N/A	链表	快慢指针
Reverse Nodes in k-Group	N/A	链表
Swap Nodes in Pairs	N/A	链表
Remove Nth Node From End of List	N/A	链表	快慢指针
Text Justification	N/A	队列
Candy	N/A	N/A	简化为子问题
Valid Palindrome	N/A	N/A	首尾指针
Plus One	N/A	N/A	模拟加法运算
Valid Number	N/A	N/A	词法分析
Add Binary	N/A	N/A	模拟加法运算
Insert Interval	N/A	N/A
Merge Intervals	N/A	N/A
Multiply Strings	N/A	N/A	模拟乘法运算
Trapping Rain Water	N/A	N/A
Valid Sudoku	N/A	N/A
Roman to Integer	N/A	N/A
Integer to Roman	N/A	N/A
Palindrome Number	N/A	N/A
Reverse Integer	N/A	N/A
ZigZag Conversion	N/A	N/A
Add Two Numbers	N/A	N/A	模拟加法运算
Median of Two Sorted Arrays	N/A	N/A
String to Integer (atoi)	STL函数	N/A
Next Permutation	STL经典算法	N/A
Recover Binary Search Tree	中序遍历	二叉树
3Sum	二分查找	N/A
3Sum Closest	二分查找	N/A
4Sum	二分查找	N/A
Single Number	位运算	N/A
Single Number II	位运算	N/A
Construct Binary Tree from Preorder and Inorder Traversal	前序中序遍历	N/A
Binary Tree Preorder Traversal	前序遍历	二叉树
Flatten Binary Tree to Linked List	前序遍历	二叉树
Interleaving String	动态规划	二叉树
Unique Binary Search Trees	动态规划	二叉树
Word Break	动态规划	N/A
Word Break II	动态规划	N/A
Palindrome Partitioning	动态规划	N/A
Palindrome Partitioning II	动态规划	N/A
Triangle	动态规划	N/A
Distinct Subsequences	动态规划	N/A
Decode Ways	动态规划	N/A
Scramble String	动态规划	N/A
Maximal Rectangle	动态规划	N/A
Edit Distance	动态规划	N/A
Climbing Stairs	动态规划	N/A
Minimum Path Sum	动态规划	N/A
Unique Paths	动态规划	N/A
Unique Paths II	动态规划	N/A
Jump Game	动态规划	N/A
Jump Game II	动态规划	N/A
Maximum Subarray	动态规划	N/A
Wildcard Matching	动态规划	N/A
Substring with Concatenation of All Words	动态规划	N/A
Sort List	合并排序	链表	快慢指针
Merge Sorted Array	合并排序	N/A
Construct Binary Tree from Inorder and Postorder Traversal	后序中序遍历	N/A
Binary Tree Postorder Traversal	后续遍历	二叉树
Combinations	回溯	N/A
Permutation Sequence	回溯	N/A
N-Queens	回溯	N/A
N-Queens II	回溯	N/A
Permutations	回溯	N/A
Permutations II	回溯	N/A
Combination Sum	回溯	N/A
Combination Sum II	回溯	N/A
Sudoku Solver	回溯	N/A
Longest Substring Without Repeating Characters	回溯	N/A
Max Points on a Line	循环遍历	N/A	排除相同的点
Longest Common Prefix	循环遍历	N/A
Longest Palindromic Substring	循环遍历	N/A
Insertion Sort List	插入排序	链表
Rotate Image	矢量旋转与平移	N/A
Longest Consecutive Sequence	类BFS	哈希表
Search in Rotated Sorted Array	类二分查找	N/A
Search in Rotated Sorted Array II	类二分查找	N/A	特殊考虑相等数据
Sqrt(x)	类二分查找	N/A
Pow(x, n)	类二进制	N/A
Divide Two Integers	类二进制	N/A
Gas Station	类合并排序	N/A
Merge k Sorted Lists	类外排序	N/A
Sort Colors	类快速排序	N/A
Remove Element	类快速排序	N/A
Search a 2D Matrix	类杨氏矩阵	N/A
Restore IP Addresses	背包问题	N/A
Sum Root to Leaf Numbers	递归	二叉树
Binary Tree Maximum Path Sum	递归	二叉树
opulating Next Right Pointers in Each Node	递归	二叉树
Populating Next Right Pointers in Each Node II	递归	二叉树
Path Sum	递归	二叉树
Path Sum II	递归	二叉树
Maximum Depth of Binary Tree	递归	二叉树
Minimum Depth of Binary Tree	递归	二叉树
Balanced Binary Tree	递归	二叉树
Symmetric Tree	递归	二叉树
Same Tree	递归	二叉树
Validate Binary Search Tree	递归	二叉树
Unique Binary Search Trees II	递归	二叉树
Binary Tree Inorder Traversal	递归	二叉树
Pascal's Triangle	递归	N/A
Pascal's Triangle II	递归	N/A
Convert Sorted List to Binary Search Tree	递归	N/A	快慢指针&反中序遍历
Convert Sorted Array to Binary Search Tree	递归	N/A	反中序遍历
Subsets	递归	N/A
Subsets II	递归	N/A
Gray Code	递归	N/A
Word Search	递归	N/A
Count and Say	递归	N/A
Generate Parentheses	递归	N/A
Letter Combinations of a Phone Number	递归	N/A
Regular Expression Matching	递归	N/A