Pow(x, n)

Description

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]

Solution(javascript)

/**
 * @param {number} x
 * @param {number} n
 * @return {number}
 */
var myPow = function(x, n) {
    if(n == 0)
        return 1;
    if(n<0){
        n = -n;
        x = 1/x;
    }
    return (n%2 == 0) ? myPow(x*x, Math.floor(n/2)) : x*myPow(x*x, Math.floor(n/2));
};