LeetCode Pow(x, n)

Implement pow(x, n).

题意：计算pow(x,n)

思路：快速求幂算法

public class Solution {
    public double pow(double x, long n) {
        double product = 1.0;
        
        long m = n;
        
        if (m < 0) m = -m;

        while (m != 0) {
            if ((m & 1) != 0) product *= x;
            m >>= 1;
            
            x *= x;
        }
        
        if (n < 0) product = 1.0 / product;
        return product;
    }
}