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);
     }
 }