# 342. Power of Four

## Description

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?

## Solutions

• class Solution {
public boolean isPowerOfFour(int n) {
return n > 0 && (n & (n - 1)) == 0 && (n & 0xaaaaaaaa) == 0;
}
}

• class Solution {
public:
bool isPowerOfFour(int n) {
return n > 0 && (n & (n - 1)) == 0 && (n & 0xaaaaaaaa) == 0;
}
};

• class Solution:
def isPowerOfFour(self, n: int) -> bool:
return n > 0 and (n & (n - 1)) == 0 and (n & 0xAAAAAAAA) == 0


• func isPowerOfFour(n int) bool {
return n > 0 && (n&(n-1)) == 0 && (n&0xaaaaaaaa) == 0
}

• function isPowerOfFour(n: number): boolean {
return n > 0 && (n & (n - 1)) == 0 && (n & 0xaaaaaaaa) == 0;
}


• /**
* @param {number} n
* @return {boolean}
*/
var isPowerOfFour = function (n) {
return n > 0 && (n & (n - 1)) == 0 && (n & 0xaaaaaaaa) == 0;
};