Pow(x, n)

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

Example 1:

Input: 2.00000, 10
Output: 1024.00000

Example 2:

Input: 2.10000, 3
Output: 9.26100

Example 3:

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

Note:

• -100.0 < x < 100.0

• n is a 32-bit signed integer, within the range [−231, 231 − 1]

class Solution {
    public double myPow(double x, int n) {
        double ans = 1;
        long absN = Math.abs((long) n);
        while (absN > 0) {
            if (absN % 2 != 0)
                ans *= x;
            absN /= 2;
            x *= x;
        }
        return n < 0 ? 1 / ans : ans;
    }
}