LeetCode Sqrt(x)

题目

Implement int sqrt(int x).

Compute and return the square root of x.

 

整数开根号，返回整数，其实就是一个二分查找的过程

 

代码：

class Solution {public:    int sqrt(int x) {long long first=0,last=x,mid;//头尾中while(last>first)//二分查找{mid=(last+first+1)/2;if(mid*mid==x)return mid;else if(mid*mid<x)first=mid;elselast=mid-1;}return first;    }};