AOC2021_04_2

void Main()
{
    var input = File.ReadAllLines(@"C:\Users\dostj\Documents\LINQPad Queries\AdventOfCode\2021\04.txt");
    //input = File.ReadAllLines(@"C:\Users\dostj\Documents\LINQPad Queries\AdventOfCode\2021\04_test.txt");

    var numbers = input[0].Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries).Select(n => int.Parse(n)).ToList();
    var boardInput = input.ToList().GetRange(1, input.Length - 1);
    var boards = new List<Board>();
    for (var i = 0; i < boardInput.Count; i += 6)
    {
        boards.Add(new Board(boardInput.GetRange(i + 1, 5)));
    }

    Board winningBoard = null;
    int winningNumber = -1;

    foreach (var number in numbers)
    {
        var boardWins = false;
        foreach (var board in boards)
        {
            if (board.HasWon)
            {
                continue;
            }

            board.MarkBoard(number);
            boardWins = board.BoardWins();
            if (boardWins)
            {
                winningBoard = board;
                winningNumber = number;
            }
        }
    }

    //boards.Dump();
    //winningBoard.Dump();

    var winningSum = 0;
    for (var i = 0; i < 5; i++)
    {
        for (var j = 0; j < 5; j++)
        {
            if (winningBoard.Markers[i,j] == 0)
            {
                winningSum += winningBoard.Input[i,j];
            }
        }
    }

    (winningSum * winningNumber).Dump();
}

// Define other methods and classes here
class Board
{
    public int[,] Input;
    public int[,] Markers;
    public int WinIPos = -1;
    public int WinJPos = -1;
    public bool HasWon = false;
    public Dictionary<int, Tuple<int, int>> PositionMap = new Dictionary<int, System.Tuple<int, int>>();

    public Board(List<string> input)
    {
        Input = new int[5,5];
        Markers = new int[5,5];
        for(var i = 0; i < 5; i++)
        {
            var numbers = input[i].Split(new char[] { ' '}, StringSplitOptions.RemoveEmptyEntries).Select(e => int.Parse(e)).ToArray();
            for (var j = 0; j < 5; j++)
            {
                Markers[i, j] = 0;
                Input[i, j] = numbers[j];
                PositionMap.Add(numbers[j], new Tuple<int, int>(i, j));
            }
        }
    }

    public void MarkBoard(int number)
    {
        if (PositionMap.ContainsKey(number))
        {
            var position = PositionMap[number];
            Markers[position.Item1, position.Item2] = 1;
        }
    }

    public bool BoardWins()
    {
        // check horizontal
        var iMarkers = 0;
        for (var i = 0; i < 5; i++)
        {
            iMarkers = 0;
            for (var j = 0; j < 5; j++)
            {
                if (Markers[i,j] == 1)
                {
                    iMarkers++;
                }
            }
            if (iMarkers == 5)
            {
                WinIPos = i;
                HasWon = true;
                return true;
            }
        }

        // check vertical
        var jMarkers = 0;
        for (var j = 0; j < 5; j++)
        {
            jMarkers = 0;
            for (var i = 0; i < 5; i++)
            {
                if (Markers[i, j] == 1)
                {
                    jMarkers++;
                }
            }
            if (jMarkers == 5)
            {
                WinJPos = j;
                HasWon = true;
                return true;
            }
        }

        return false;
    }
}