find method

Implementation

int? find(List<T> a) {
  if (a.length > length) {
    return null;
  }

  int? result;
  int nLength = length - a.length;
  for (int i = 0; i < nLength; ++i) {
    result = i;
    for (int j = 0; j < a.length; ++j) {
      if (this[i] != a[j]) {
        result = null;
        break;
      }
    }
  }
  return result;
}