Pow(x, n)

Pow(x, n)

Implement pow(x, n).

Java代码：

public class Solution {    public double pow(double x, int n) {    if (x == 0) return 0;     if (x == 1) return 1;    if (n == 0) return 1;     if (n == 1) return x;    if (x == -1) return (n % 2) == 0 ? 1 : -1;     if (n < 0 ) return 1/ pow (x, -n);    if (n == 2) return x * x;    int halfPow = n/2;     return pow(pow(x,halfPow),2) * pow(x, n%2);     }}