342 Power Of Four

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?

impl Solution {
    pub fn is_power_of_four(n: i32) -> bool {
       // bin of 2 is 10, 100 is 4, 1000 is 8, 10000 is 16
       // so 100 ^ 011 is 0 for 2, onlt check extra if n % 3 == 0
       return (n & (n -1)) == 0 && n % 3 == 1

      
    }
}