Sqrt(x)

special

牛顿迭代法

public class Solution {
    public int sqrt(int x) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if(x <= 0){
            return x;
        }
        double last = 0;
        double cur = x;
        while(Math.abs(cur - last) > 0.0001){
            last = cur;
            cur = (cur + x / cur) / 2;
        }
        return (int)cur;
    }
}