LeetCode 69. Sqrt(x)

Implement t sqrt(int x).

Compute and return the square root of x.

题意：求平方根

解析：二分算法，暴力肯定超时

java代码：

public int mySqrt(int x) {

        if (x <= 1) {
            return x;
        }

        int begin = 1;
        int end = x;
        int middle = 0;

        while (begin <= end) {
            middle = begin + (end - begin) / 2;
            if (middle == x / middle) {
                return middle;
            } else {
                if (middle < x / middle) {
                    begin = middle + 1;
                } else {
                    end = middle - 1;
                }
            }

        }
        return end;
    }