[Leetcode] Sqrt(x)

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;
    }
};