数值的整数次方

public class Solution {
    public double Power(double base, int exponent) {
        if(exponent == 0)return 1;
        if(exponent == 1)return base;
        boolean flag = false;
        if(exponent < 0) {
            exponent = -exponent;
            flag = true;
        }
        double pow = Power(base * base, exponent/2);
        if(exponent/2 == 1) {
            pow = pow * base;
        }
        return flag == true?1/pow:pow;
    }
}