342. Power of Four

Given an integer n, return true if it is a power of four. Otherwise, return false.

An integer n is a power of four, if there exists an integer x such that n == 4x.

 

Example 1:

Input: n = 16
Output: true

Example 2:

Input: n = 5
Output: false

Example 3:

Input: n = 1
Output: true

 

Constraints:

• -231 <= n <= 231 - 1

 

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

Solution:

In JS:

var isPowerOfFour = function(n) {

    let result = false;

    let numOfSqrt = parseInt(Math.sqrt(n))+1;

    for(let index = 0; index<=numOfSqrt; index++){

      let power = Math.pow(4, index);

      if(n === power) result = true;

      else result;

    }   

    return result;

};