題目描述
給定一個double類型的浮點數(shù)base和int類型的整數(shù)exponent。求base的exponent次方。

public class Solution {
    
    public double Power(double base, int exponent){
        
        if(exponent == 0){
            
            return 1;
        }
        if(exponent < 0) {
            
            int temp = - exponent;
            double result = recursion(base, temp);
            result = 1/result;
            return result;
        }else {
            
            double result = recursion(base, exponent);
            return result;
        }
    }
    private double recursion(double base, int exponent) {
        
        if(exponent == 1) {
            
            return base;
        }
        if(exponent % 2 == 0) {
            
            double temp = recursion(base,exponent/2);
            temp *= temp;
            return temp;
        }else {
            
            double temp = recursion(base,exponent/2);
            temp *= temp * base;
            return temp;
        }
    }
}