You are standing at position 0 on an infinite number line. There is a goal at position target. On each move, you can either go left or right. During the n-th move (starting from 1), you take n steps. Return the minimum number of steps required to rea…

Given an integer, write an algorithm to convert it to hexadecimal. For negative integer, two’s complement method is used. Note: All letters in hexadecimal (a-f) must be in lowercase. The hexadecimal string must not contain extra leading 0s. If the nu…

Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the…

转载:http://www.cnblogs.com/grandyang/p/4756677.html Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array. For example,Given nums = [0, 1, 3] return 2. Note:Your algorithm should run in li…

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array. Example 1 Input: [3,0,1] Output: 2 Example 2 Input: [9,6,4,2,3,5,7,0,1] Output: 8 Note:Your algorithm should run in linear runtime c…

题目 在一根无限长的数轴上,你站在0的位置.终点在target的位置. 每次你可以选择向左或向右移动.第 n 次移动(从 1 开始),可以走 n 步. 返回到达终点需要的最小移动次数. 示例 1: 输入: target = 3 输出: 2 解释: 第一次移动,从 0 到 1 . 第二次移动,从 1 到 3 . 示例 2: 输入: target = 2 输出: 3 解释: 第一次移动,从 0 到 1 . 第二次移动,从 1 到 -1 . 第三次移动,从 -1 到 2 . 解析 class Solu…

问题描述: You are standing at position 0 on an infinite number line. There is a goal at position target. On each move, you can either go left or right. During the n-th move (starting from 1), you take n steps. Return the minimum number of steps required…

136. Single Number 除了一个数字,其他数字都出现了两遍. 用亦或解决,亦或的特点:1.相同的数结果为0,不同的数结果为1 2.与自己亦或为0,与0亦或为原来的数 class Solution { public: int singleNumber(vector<int>& nums) { if(nums.empty()) ; ; ;i < nums.size();i++) res ^= nums[i]; return res; } }; 137. Single N…

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array. For example, Given nums = [0, 1, 3] return 2. Note: Your algorithm should run in linear runtime complexity. Could you implement it u…

Given an array of integers, every element appears twice except for one. Find that single one. Note:Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory? 本来是一道非常简单的题,但是由于加上了时间复杂度必须是O(n),并且空间复杂度为O(1)…