leetcode 172. Factorial Trailing Zeroes

Seawolf

1. Given an integer n, return the number of trailing zeroes in n!.
   
2. 
   
3. Example 1:
   
4. 
   
5. Input: 3
   
6. Output: 0
   
7. Explanation: 3! = 6, no trailing zero.
   
8. Example 2:
   
9. 
   
10. Input: 5
    
11. Output: 1
    
12. Explanation: 5! = 120, one trailing zero.
    
13. Note: Your solution should be in logarithmic time complexity.

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解题思路：1个5对应1个0，25对应2个0，125对应3个0，依次类推....

1. class Solution {
   
2.     public int trailingZeroes(int n) {
   
3.         int res = n/5;
   
4.         
   
5.         while(n / 5 > 0){
   
6.             
   
7.             n = n/ 5;
   
8.             res = res + n/5;
   
9.         }
   
10.         
    
11.         return res;
    
12.     }
    
13.    
    
14. }

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