sqrt(x).cpp

#include <bits/stdc++.h>
using namespace std;

class Solution {
public:
    int mySqrt(int x) {
        if (x == 0) return 0;
        int left = 1, right = x;
        while (left <= right) {
            int mid = left + (right - left) / 2;
            if (mid <= 1.0 * x / mid) left = mid + 1;
            else right = mid - 1;
        }
        return right;
    }
};