数值的整数次方

给定一个double类型的浮点数base和int类型的整数exponent。求base的exponent次方。

public class Solution {
    public double PowerPositive(double base, int exponent) {
        if(exponent==0) return 1;
        if(exponent==1) return base;
        double muti = Power(base,exponent/2);
        muti = muti * muti;
        if(exponent%2==1){
            muti = muti * base;
        }
        return muti;
    }
    public double Power(double base, int exponent) {
        int ex = Math.abs(exponent);
        double re = PowerPositive(base,ex);
        if(exponent<0){
            re = 1 / re;
        }
        return re;
    }
}