Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

参考：http://standalone.iteye.com/blog/1847368

参考的是一个用二分查找实现的，这道题还可以用什么牛顿法之类的

如果middle * middle > x在左半部分查找，如果middle * middle < x在有半部分查找。初始状态low = 0, high = x

 

public class Solution {
    public int sqrt(int x) {
       double low = 0;
       double precision = 0.000000001;
       double high = x;
       while((high - low ) >precision){
           double middle = (low + high) / 2;
           if(x > middle * middle){
               low = middle;
           }
           if(x < middle * middle){
               high = middle;
           }
           if(x == middle * middle){
               return (int)Math.floor(middle);
           }
       }//while
       return (int)Math.floor(high);
    }
}