Power of Four

Description

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example 1:

Input: 16
Output: true

Example 2:

Input: 5
Output: false

Follow up: Could you solve it without loops/recursion?

Solution(javascript)

/**
 * @param {number} num
 * @return {boolean}
 */
var isPowerOfFour = function(n) {
    while (n > 1) {
    n /= 4
  }
  return n === 1
};