题目：
Given an integer, write a function to determine if it is a power of three.
Follow up:
Could you do it without using any loop / recursion?
链接：
https://leetcode.com/problems/power-of-three/?tab=Description
3/7/2017
不满足题目的解法，注意n == 1也是true
1 public class Solution { 2 public boolean isPowerOfThree(int n) { 3 if (n == 1) return true; 4 if (n == 2) return false; 5 while (n > 3 && n % 3 == 0) n /= 3; 6 if (n == 3) return true; 7 return false; 8 } 9 }
可以简化为
1 public class Solution { 2 public boolean isPowerOfThree(int n) { 3 if (n < 1) { 4 return false; 5 } 6 7 while (n % 3 == 0) { 8 n /= 3; 9 } 10 11 return n == 1; 12 } 13 }
题目给出的4种解法，然而并不觉得比native解法好到哪里去。