Pow(x, n)

Problem Description

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

Solution (Go)

func myPow(x float64, n int) float64 {
    var pow func(x float64, n int) float64
	pow = func(x float64, n int) float64 {
		if n == 0 {
			return 1
		}
		if n%2 == 0 {
			return pow(x*x, n/2)
		}
		return x * pow(x*x, (n-1)/2)
	}
	if n < 0 {
		return 1 / pow(x, -n)
	}
	return pow(x, n)
}