Leetcode: Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

依然二分法….这道题虽然简单，但是有一些细节需要注意，我是提交了好几遍才通过的！

参考代码：

class Solution {public:    int mySqrt(int x)     {        if (x < 2) return x;        int left = 1;        int right = x / 2;        int result;        while (left <= right)        {            int middle = (left + right) / 2;            if (x / middle < middle)                right = middle - 1;            else if (x / middle > middle)            {                left = middle + 1;                result = middle;            }            else return middle;        }        return result;    }};