69. Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

题意：求x的平方根。

直接看代码：

public class Solution {    public int mySqrt(int x) {        if(x == 0)            return 0;        if(x ==1 || x==2 || x==3)            return 1;        int left = 2;        int right = x/2;        while(true){            int mid = left + (right-left)/2;            if(mid > x/mid){                right = mid-1;            }else{                if(mid+1 > x/(mid+1))                    return mid;                left = mid+1;            }        }    }}

通过二分法，在2和x/2中寻找答案。