342. Power Of Four¶

LeetCode Problem View on GitHub

342. Power of Four

Easy

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¶

class Solution {
    public boolean isPowerOfFour(int n) {
        if (n <= 0) 
            return false;
        while (n > 1) {
            if (n % 4 != 0)
                return false;
            n /= 4;
        }
        return true;
    }
}

Complexity Analysis¶

• Time Complexity: O(?)
• Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here