/// <summary>
/// Find N numbers with expected sum
/// </summary>
/// <param name="sum">Expected sum</param>
/// <param name="count">Number of elements to find</param>
/// <returns>N numbers whose sum is equal to expected sum, ordered by smaller ones first</returns>
public int[] FindNWithSum(int sum, int count = 2)
{
if (count < 1)
{
throw new ArgumentException("Count must be at least 1", nameof(count));
}
if (SortedNumbers.Count < count)
{
return(null);
}
if (count == 1)
{
return(SortedNumbers.Contains(sum) ? new[] { sum } : null);
}
var calculatorWithoutFirst = new ExpenseCalculator(SortedNumbers.Skip(1));
var setIfFirstIsThere = calculatorWithoutFirst.FindNWithSum(sum - SortedNumbers.First(), count - 1);
if (setIfFirstIsThere != null)
{
// first element should be part of result
var result = new List <int> {
SortedNumbers.First()
};
result.AddRange(setIfFirstIsThere);
return(result.ToArray());
}
// first element should not be part of result
return(calculatorWithoutFirst.FindNWithSum(sum, count));
}
static void Main(string[] args)
{
var expenses = File.ReadAllLines("input.txt").Select(int.Parse);
var expenseCalculator = new ExpenseCalculator();
// Part 1
Console.WriteLine(expenseCalculator.Magic(expenses, 2));
// Part 2
Console.WriteLine(expenseCalculator.Magic(expenses, 3));
}
public void LoadInput()
{
ExpenseCalculator = new ExpenseCalculator(InputGetter.ReadInputLinesInt(1));
}