leetcode 326. Power of Three

Seawolf

1. Given an integer, write a function to determine if it is a power of three.
   
2. 
   
3. Example 1:
   
4. 
   
5. Input: 27
   
6. Output: true
   
7. Example 2:
   
8. 
   
9. Input: 0
   
10. Output: false
    
11. Example 3:
    
12. 
    
13. Input: 9
    
14. Output: true
    
15. Example 4:
    
16. 
    
17. Input: 45
    
18. Output: false
    
19. Follow up:
    
20. Could you do it without using any loop / recursion?

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1. class Solution {
   
2.     public boolean isPowerOfThree(int n) {
   
3.         if(n == 0) return false;
   
4.         if(n == 1) return true;
   
5.         
   
6.         if(n % 3 == 0)
   
7.             return isPowerOfThree(n/3);
   
8.         else
   
9.             return false;
   
10.     }
    
11. }

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1. class Solution {
   
2.     public boolean isPowerOfThree(int n) {
   
3.         
   
4.         return (n > 0 && 1162261467 % n == 0);
   
5.     }
   
6. }

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