Leetcode134: Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

class Solution {public:    int mySqrt(int x) {        if(x<=1)            return x;        int l = 1;        int r = x/2;        while(l<=r)        {            int mid = (r+l)/2;            if(mid== x/mid)                return mid;            else if(mid > x/mid)                r = mid-1;            else                l = mid+1;        }        return r;    }};