Leetcode: sqrt

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