题目:求平方根 难度:Easy 题目内容: Compute and return the square root of x, where x is guaranteed to be a non-negative integer. Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned. 翻译: 计算并返回x的平…

题目难度:Medium 题目: 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: The solution set must not contain duplicate quadrup…

题目: Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. 翻译: 给定一组整数,两个数字的返回索引,它们的和会等于一个特定…

题目:求所有全排列 难度:Medium 题目内容: Given a collection of distinct integers, return all possible permutations. 翻译:给定一组各不相同的整数,返回所有可能的排列. Example: Input: [1,2,3] Output: [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ] 我的思路:每种情况中,每一个元素只出现一次,只是之间的顺序不同,那么…

题目: Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. 翻译: 给定一组整数,两个数字的返回索引,它们的和会等于一个特定…

题目难度:Medium Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis form…

题目难度:hard There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). Example 1: nums1 = [1, 3] nums2 = [2] The median is 2.0 Example 2: n…

题目:两整数相除 难度:Medium 题目内容: Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator. Return the quotient after dividing dividend by divisor. The integer division should truncate toward zero. 翻…

题目难度:Medium Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis form…

题目难度:hard There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). Example 1: nums1 = [1, 3] nums2 = [2] The median is 2.0 Example 2: n…

题目难度:Medium 题目: Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Note: The solution set must not contain duplicate triplets. 翻译: 给定一个n个整数的数组S,S…

题目难度:Medium 题目: 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 input would have exactly one solution. 翻译: 给定一个n个整数的数组S,在S…

题目:验证二叉搜索树 难度:Medium 题目内容: Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node co…

题目:矩阵单词搜索 难度:Medium 题目内容: 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 horizontally or vertically neighboring. The same…

题目:矩阵置0 难度:Easy 题目内容:   Given a set of distinct integers, nums, return all possible subsets (the power set). Note: The solution set must not contain duplicate subsets. 翻译: 给定一组不同的整数,nums,返回所有可能的子集(包括空集和自身). 注意:解决方案集不能包含重复的子集. Example: Input: nums = […

题目:唯一路径(机器人走方格) 难度:Medium 题目内容: A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner o…

题目:通配符匹配 难度:hard 题目内容: Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '*'. '?' Matches any single character. '*' Matches any sequence of characters (including the empty sequence). The matchin…

题目:接雨水 难度:hard 题目内容: 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. The above elevation map is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In…

题目中文:求最长回文子串 题目难度:Medium 题目内容: Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. 翻译: 给定一个字符串s,找出s中最长的回文子串.你可以假设s的最大长度是1000. 什么叫回文子串? 就是字符串中,满足能正读反读都一样的子串,就是回文子串.如下所示 Input: "babad"…

题目难度:Medium 题目: You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. You may assume…

题目难度:Easy 题目: Given a sorted array, remove the duplicates in-place such that each element appear only once and return the new length. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extr…

题目难度:Medium 题目: 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 input would have exactly one solution. 翻译: 给定一个n个整数的数组S,在S…

题目难度:Medium 题目: Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Note: The solution set must not contain duplicate triplets. 翻译: 给定一个n个整数的数组S,S…

题目:有效的括号序列 难度:Easy 题目内容: Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must…

题目:解码方法数 难度:Medium 题目内容: A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given a non-empty string containing only digits, determine the total number of ways to decode…

题目:合并已排序数组 难度:Easy 题目内容: Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array. 翻译: 给定两个排序的整数数组nums1和nums2,将nums2合并到nums1中作为一个排序数组. 注意: nums1和nums2中初始化的元素数量分别为m和n. nums1有足够的空间(大小大于或等于m+n)来容纳nums2中的额外元素. 我的思路:此处和归…

题目:最大的矩形柱状图 难度:hard 题目内容: 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. 翻译: 给定n个非负整数表示直方图的杆高度,其中每个条的宽度为1,找出直方图中最大矩形的面积. Above is a histogra…

题目:矩阵置0 难度:Easy 题目内容: Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place. 翻译: 给定一个m x n矩阵,如果一个元素是0,就把它的整行和列设为0. 要求:就地置0. Example 1: Input: [   [1,1,1],   [1,0,1],   [1,1,1] ] Output: [   [1,0,1],   [0,0,0],  …

191. Number of 1 Bits Total Accepted: 87985 Total Submissions: 234407 Difficulty: Easy Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11'…

题目:数组加一 难度:Easy 题目内容:   Given a non-empty array of digits representing a non-negative integer, plus one to the integer. The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a sin…