// #define Day4
#if Day4
using AoC2021;
var parts = File.ReadAllText("day4/input").Split("\n\n");
var numbers = parts[0].Split(",").Select(int.Parse);

var boards = parts.Skip(1).Select(ToBoard).ToList();

int numberOfBoards = boards.Count;
foreach (var num in numbers) {
    var won = boards.Select((board, i) => new {bingo = CheckBoard(num, board), index = i}).Where(a => a.bingo).ToList();

    // For PartTwo
    if (won.Count > 0 && boards.Count == 1) {
        int[,] winningBoard = boards[won.First().index];
        CalculateScore(winningBoard, num);
        break;
    }
    if (won.Count > 0 && boards.Count == numberOfBoards) {
        int[,] winningBoard = boards[won.First().index];
        CalculateScore(winningBoard, num);
    }

    var wonIndices = won.Select(w => w.index).ToHashSet();
    boards = boards.Where((board, index) => !wonIndices.Contains(index)).ToList();
}

void CalculateScore(int[,] board, int lastNum) {
    long sum = 0;
    for (int row = 0; row < 5; row++) {
        for (int col = 0; col < 5; col++) {
            if (board[row, col] >= 0) {
                sum += board[row, col];
            }
        }
    }
    Console.WriteLine(sum * lastNum);
}

bool CheckBoard(int num, int[,] board) {
    bool bingo = false;
    for (int row = 0; row < 5; row++) {
        for (int col = 0; col < 5; col++) {
            if (board[row, col] == num) {
                board[row, col] *= -1;
                bingo |= CheckRow(board, row) || CheckCol(board, col);
            }
        }
    }
    return bingo;
}

bool CheckRow(int[,] board, int row) => Enumerable.Range(0, 5).All(col => board[row, col] < 0);
bool CheckCol(int[,] board, int col) => Enumerable.Range(0, 5).All(row => board[row, col] < 0);

int[,] ToBoard(string s) {
    int[,] board = new int[5,5];
    s.Split("\n")
        .ForEachIndex((l, row) => l.Split(" ", StringSplitOptions.RemoveEmptyEntries)
        .ForEachIndex((num, col)=> 
            board[row,col] = Int32.Parse(num)));
    return board;
}
#endif