code: public ProblemInput getProblemInput(final int index) {
  		final List<ProblemInput> inputs = getProblemInputs();
  		if (index < 0 || inputs.size() <= index) {
  			throw new ArrayIndexOutOfBoundsException();
  		}
  		return inputs.get(index);
  	}
docs: Shortcut method for reducing law of Demeters issues.
  
  @param index Index of the problem input to retrieve.
  @return Problem input instance required.
  @throws ArrayIndexOutOfBoundsException If the given index is not valid.