Implement int sqrt(int x).

Compute and return the square root of x.

牛顿迭代法, 碉堡了。

class Solution {public:    int sqrt(int x) {        double ans = x;        while (abs(ans * ans - x) > 0.0001) {            ans = (ans + x / ans) / 2;        }        return (int)ans;    }};