实现sqrt(x)

Implement int sqrt(int x).

class Solution {
public:
    int sqrt(int x) {
        int min = 0;
        int max = INT_MAX;
        int mid;
        while(max>min)
        {
            if(max-min==1) return min;
            mid = (max+min)/2;
            if(x/mid==mid) return mid;    //mid*mid==x 会超出范围
            else if(x/mid>mid)
                min = mid;                   
            else max = mid;
        }
        return mid;
    }
};