王川的私房菜

Clone GrapClone an undirected graph. Each node in the graph contains a label and a list of its neighbors.OJ's undirected graph serialization:Nodes are labeled uniquely.We use # as

Surrounded Regions Total Accepted: 3163 Total Submissions: 22161My SubmissionsGiven a 2D board containing 'X' and 'O', capture all regions surrounded by 'X'.A region is captured by f

Convert Sorted Array to Binary Search Tree Given an array where elements are sorted in ascending order, convert it to a height balanced BST.算法思想：每次找寻中间的元素作为父亲节点/** * Definit

Construct Binary Tree from Preorder and Inorder Traversal Given preorder and inorder traversal of a tree, construct the binary tree.Note:You may assume that duplicates do not exist in th

Same Tree Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical and the nodes have the same va

Unique Binary Search Trees II Given n, generate all structurally unique BST's (binary search trees) that store values 1...n.For example,Given n = 3, your program should return all 5 uniq

Restore IP Addresses Given a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given "25525511135",return ["255.255.11.135",

Word Search Given a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizo

Search a 2D Matrix Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:Integers in each row are sorted from left to righ

Text Justification Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.You should pack your words i

Add Binary Given two binary strings, return their sum (also a binary string).For example,a = "11"b = "1"Return "100".class Solution {public: string addBinary(string a, s

Spiral Matrix II Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.For example,Given n = 3,You should return the following matrix:[ [

Pow(x, n) Implement pow(x, n).算法思想：递归TLE，二分法：class Solution {public: double pow(double x, int n) { if(n==0)return 1.0; if(n<0){ if(n==INT_M

Anagrams Given an array of strings, return all groups of strings that are anagrams.Note: All inputs will be in lower-case.class Solution {public: vector anagrams(vector &s

Multiply Strings Given two numbers represented as strings, return multiplication of the numbers as a string.Note: The numbers can be arbitrarily large and are non-negative.class So

Search Insert Position Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You may ass

Search in Rotated Sorted Array Suppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).You are given a target value t

Substring with Concatenation of All Words You are given a string, S, and a list of words, L, that are all of the same length. Find all starting indices of substring(s) in S that is a concate

Reverse Nodes in k-Group Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.If the number of nodes is not a multiple of k then left-out nodes

Merge k Sorted Lists Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.算法思想：每次从lists中找一个值最小的加到链中，最小的那个项指向它的下一个节点/** * Definitio

3Sum Closest Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each

Integer to Roman Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999.class Solution {public: string intToRoman(int nu

Palindrome Number Determine whether an integer is a palindrome. Do this without extra space.click to show spoilers.Some hints:Could negative integers be palindromes? (ie, -1)If you a

Maximal Rectangle Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area.算法思想：最大子矩阵问题class Solution {public:

Two Sum Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two numbers such that they add up to

4Sum Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target.Note:

Trapping Rain Water Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.For example, Giv

Climbing Stairs You are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Gas Station Total Accepted: 5589 Total Submissions: 23851My SubmissionsThere are N gas stations along a circular route, where the amount of gas at station i is gas[i].You have a car wi

Candy There are N children standing in a line. Each child is assigned a rating value.You are giving candies to these children subjected to the following requirements:Each child must

Single Number Total Accepted: 9511 Total Submissions: 21027My SubmissionsGiven an array of integers, every element appears twice except for one. Find that single one.Note:Your algori

Single Number II Given an array of integers, every element appears three times except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it

LRU Cache Total Accepted: 3543 Total Submissions: 28382My SubmissionsDesign and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations

Longest Valid Parentheses Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.For "(()", the longest val

Largest Rectangle in Histogram Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.

Evaluate Reverse Polish Notation Total Accepted: 3892 Total Submissions: 20348My SubmissionsEvaluate the value of an arithmetic expression in Reverse Polish Notation.Valid operators ar

Binary Tree Inorder Traversal bGiven a binary tree, return the inorder traversal of its nodes' values.For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3return

Binary Tree Level Order Traversal II Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For ex

Insertion Sort List Total Accepted: 4162 Total Submissions: 16278My SubmissionsSort a linked list using insertion sort./** * Definition for singly-linked list. * struct Lis

Reorder List Total Accepted: 4205 Total Submissions: 22851My SubmissionsGiven a singly linked list L: L0→L1→…→Ln-1→Ln,reorder it to: L0→Ln→L1→Ln-1→L2→Ln-2→…You must do this in-place