private void validateInput(int[] numbers, int position) {
    if (numbers == null || position <= 0) {
      throw new IllegalArgumentException(
          "You can't pass null arrays or position values minor than 0 as parameter.");
    }
  }
Iterative solution to solve this problem. This algorithm is based on a complexity order equals
to O(N) and space O(N) because you need to go through the full set numbers two times and you
need a map to store the number of repetitions for every element.
src/main/java/com/github/pedrovgs/problem45/FindNthMostRepeatedElement.java