342. Power of Four

JIAKAOBO

LeetCode

感谢赞助!

• ㊗️
• 大家
• offer
• 多多！

Problem

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

Code

class Solution {
    public boolean isPowerOfFour(int num) {
        if(num <= 0) return false;

        while(num % 4 == 0){
            num /= 4;
        }

        return num == 1;
    }
}

class Solution {
    public boolean isPowerOfFour(int num) {
        return (Math.log(num) / Math.log(4)) % 1 == 0;
    }
}