Power of Four - Easy - LeetCode

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?

public class Solution {
 public bool IsPowerOfFour(int num) {
 if(num<=0){
 return false; 
 }
 
 if((num & (num-1))!= 0){
 return false;
 }
 
 return (num-1)%3==0;
 }
}

Time Complexity: O(1)

Space Complexity: O(1)