Pow(x, n)

Implement pow(x, n), which calculates x raised to the power n (i.e., xn).

Example 1:

Input: x = 2.00000, n = 10
Output: 1024.00000

Example 2:

Input: x = 2.10000, n = 3
Output: 9.26100

Example 3:

Input: x = 2.00000, n = -2
Output: 0.25000
Explanation: 2-2 = 1/22 = 1/4 = 0.25

Constraints:

• -100.0 < x < 100.0
• -231 <= n <= 231-1
• n is an integer.
• Either x is not zero or n > 0.
• -104 <= xn <= 104

Approach

• We have two conditions one with odd and one with even
  

class Solution {
    public double myPow(double x, int n) {
        long N = n;
        if (n < 0) {
            x = 1 / x;
            N = -N;
        }
        double res = 1;
        while (N > 0) {
            if (N % 2 == 1) {
                res *= x;
            }
 
            x *= x;
            N /= 2;
        }
 
        return res;
    }
}