Seawolf 发表于 2019-9-15 05:15:07

leetcode 326. Power of Three

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

Example 1:

Input: 27
Output: true
Example 2:

Input: 0
Output: false
Example 3:

Input: 9
Output: true
Example 4:

Input: 45
Output: false
Follow up:
Could you do it without using any loop / recursion?

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

class Solution {
    public boolean isPowerOfThree(int n) {
      
      return (n > 0 && 1162261467 % n == 0);
    }
}
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