172. Factorial Trailing Zeroes

Given an integer n, return the number of trailing zeroes in n!.

Example 1:

Input: 3
Output: 0
Explanation: 3! = 6, no trailing zero.

Example 2:

Input: 5
Output: 1
Explanation: 5! = 120, one trailing zero.

public class Solution {   
    public int trailingZeroes(int n) {   
        int res = 0;
        double p5 = 5;
        while(n >=  p5) {
            res += n / p5;
            p5 *= 5;
        }
        return res;
    }   
}