035 Divide SubString

given a number n and a length k
now we need to know that from all the substring of number n with length of k, how many of these can be divisible by n.
return the number of substrings that meets the requirement.

it’s very straight forward.

public int divideSubstring(int n, int k) {
  if (n == 0 || k == n) return 0;

  String str = Integer.toString(n);
  int len = str.length();
  int count = 0;
  for (int i = 0; i <= len - k; i++) {
    String cur = str.substring(i, i + k);
    if (Integer.parseInt(cur) % k == 0) {
      count++;
    }
  }
  return count;
}