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
class Solution { public boolean isPowerOfFour(int num) { return Math.log10(num) / Math.log10(4) % 1 == 0; } }
原文：https://www.cnblogs.com/wentiliangkaihua/p/11702720.html