Sqrt(x)

1.二分查找

2.特殊情况

0

1

 

class Solution {public:    int sqrt(int x) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        if(x==0)return 0;        if(x==1)return 1;        long long l=0,r=x,mid=0;        while(l<r){            mid=(l+r)/2;            if(mid*mid>x){                r=mid;            }else if(mid*mid<x){                l=mid+1;            }else return mid;        }        return r-1;            }};