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Given an integer (signed 32 bits), write a function to check whether it is a power of 4.
Example:
Given num = 16, return true. Given num = 5, return false.
Follow up: Could you solve it without loops/recursion?
思路：
可以沿用求3的幂次中的思路，验证log4N是否为整数来判断。
解法：
1 public class Solution 2 { 3 public boolean isPowerOfFour(int num) 4 { 5 double n = Math.log10(num) / Math.log10(4); 6 7 if(n == (int)n) 8 return true; 9 else 10 return false; 11 } 12 }
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原文地址：http://www.cnblogs.com/wood-python/p/5828095.html
