LEETCODE 326

Given an integer, write a function to determine if it is a power of three.

class Solution {public:    bool isPowerOfThree(int n) {        if(n == 0)            return false;        if (1 == n)            return true;      while(n){if(n%3 != 0)return false;else{    if (3 == n )return true;n = n/3;}}return true;            }};

递归：

   if (n == 1) return true;    else if (n == 0) return false;    else if (n % 3 == 0)        return isPowerOfThree(n / 3);    else return false;