Math Bit Manipulation
Learner Level

Implement the powerOfFourCheck method that checks whether a number is a power of four.

The input is an integer n.

Your task is to check whether n is a power of four. A number is a power of four if it can be written as 4^k for some non-negative integer k.

For example, 16 is a power of four because 4 × 4 = 16. 5 is not a power of four.

Example 1
Input:
n (int) = 16
Return:
(boolean) true
Example 2
Input:
n (int) = 5
Return:
(boolean) false
Example 3
Input:
n (int) = 1
Return:
(boolean) true

Keep dividing the number by 4 while it is exactly divisible by 4.

If the number finally becomes 1, then it was made only by multiplying 4 repeatedly. If it becomes any other value, then it is not a power of four.

Negative numbers and zero are never powers of four.

Pseudocode:

function powerOfFourCheck(n):
    if n <= 0:
        return false
    while n % 4 == 0:
        n = n / 4
    return n == 1
Run your code to see the result.