/// <summary> /// Check for the two product numbers that only differs in one char and return the number without these char. /// </summary> /// <returns>The product number without the diffing char or an empty string if nothing was found.</returns> /// <param name="numbers">A List of product numbers.</param> public string Part2(string[] numbers) { foreach (string numberOne in numbers) { foreach (string numberTwo in numbers) { int pos = PartNumber.DiffOnOnePosition(numberOne, numberTwo); if (pos != -1) { return(PartNumber.RemoveChar(numberOne, pos)); } } } return(string.Empty); }