lintcode-medium-Pow(x, n)

Posted 2020-07-03 哥布林工程师

Implement pow(x, n).

 

 Notice

You don‘t need to care about the precision of your answer, it‘s acceptable if the expected answer and your answer ‘s difference is smaller than 1e-3.

Example

Pow(2.1, 3) = 9.261
Pow(0, 1) = 0
Pow(1, 0) = 1

Challenge

O(logn) time

 

public class Solution {
    /**
     * @param x the base number
     * @param n the power number
     * @return the result
     */
    public double myPow(double x, int n) {
        // Write your code here
        
        if(n == 0)
            return 1;
        if(n == 1)
            return x;

        if(n > 1){
            if(n % 2 == 0){
                double temp = myPow(x, n / 2);
                return temp * temp;
            }
            else{
                return myPow(x, n - 1) * x;
            }
        }
        else{
            return 1 / myPow(x, -n);
        }
    }
}