Counting trailing zeros of numbers resulted from factorial

Question

I\'m trying to count trailing zeros of numbers that are resulted from factorials (meaning that the numbers get quite large). Following code takes a number, compute the facto

Answer 1

The best with logarithmic time complexity is the following:

public int trailingZeroes(int n) {
    if (n < 0)
        return -1;

    int count = 0;
    for (long i = 5; n / i >= 1; i *= 5) {
        count += n / i;
    }

    return count;
}

shamelessly copied from http://www.programcreek.com/2014/04/leetcode-factorial-trailing-zeroes-java/