Pow(x, n)

题目

Implement pow(x, n).

方法

注意Integer.MIN_VALUE值和Integer.MAX_VALUE值。

    public double pow(double x, int n) {    if (n == 0) {    return 1;    }        if (n == Integer.MIN_VALUE && x == -1) {    return 1;    }    boolean flag = false;    if (n < 0) {    n = - n;    flag = true;    }        double pro = 1;        double remain = 1;        double cur = x;                while (n > 1) {            if ((n & 1) == 1) {                remain = remain * cur;            }            n = n >> 1;            cur = cur * cur;                    }        pro = cur * remain;        if (flag) {        pro = 1 / pro;        }        return pro;    }