172. Factorial Trailing Zeroes

Given an integer n, return the number of trailing zeroes in n!.
**Note: **Your solution should be in logarithmic time complexity.

Solution:

class Solution {
public:
    int trailingZeroes(int n) {
        int r = 0;
        while(n >= 5){
            n = n / 5;
            r+=n;
        }
        return r;
    }
};