using System;

using System.Collections.Generic;

using System.Linq;

​

class Program

{

    static char[][] createFarm(string s)

    {

        string cleaned = s.Replace("[", "").Replace("]", "").Replace(",", "");

        string[] rows = cleaned.Split("||");

        return rows.Select(r => r.ToCharArray())

            .ToArray();

    }

​

    static bool isSquareFarm(char[][] farm)

    {

        foreach (char[] row in farm)

        {

            if (row.Length != farm.Length)

            {

                return false;

            }

        }

        return true;

    }

​

    static void lookAround(char currentChar, char[][] farm, int i, int j, HashSet<string> visited)

    {

        string key = i + "," + j;

        if (visited.Contains(key))

            return;

​

        visited.Add(key);

​

        Tuple<int, int>[] coordsToCheck =

        {

            new(i + 1, j),

            new(i - 1, j),

            new(i, j + 1),

            new(i, j - 1),

        };

​

        foreach (Tuple<int, int> coord in coordsToCheck)

        {

            int x = coord.Item1, y = coord.Item2;

            if (x < 0 || x >= farm.Length || y < 0 || y >= farm.Length) continue;

            if (farm[x][y] != currentChar) continue;

            lookAround(currentChar, farm, x, y, visited);

        }

    }

​

    static int totalCost(string s)

    {

        char[][] farm = createFarm(s);

​

        if (!isSquareFarm(farm))

            throw new Exception("Go away and come back with a square farm.");

​

        HashSet<string> globalVisited = new HashSet<string>();

        List<HashSet<string>> regions = new List<HashSet<string>>();

​

        for (int i = 0; i < farm.Length; i++)

        {

            for (int j = 0; j < farm[i].Length; j++)

            {

                string key = i + "," + j;

                if (globalVisited.Contains(key))

                    continue;

​

                HashSet<string> region = new HashSet<string>();

                lookAround(farm[i][j], farm, i, j, region);

                regions.Add(region);

​

                foreach (string cell in region)

                    globalVisited.Add(cell);

            }

        }

​

        int totalCost = 0;

        foreach (HashSet<string> region in regions)

        {

            int area = region.Count;

            int perimeter = 0;

​

            string anyCell = region.First();

            int anyI = int.Parse(anyCell.Split(',')[0]);

            int anyJ = int.Parse(anyCell.Split(',')[1]);

            char regionLetter = farm[anyI][anyJ];

​

            foreach (string cell in region)

            {

                string[] parts = cell.Split(',');

                int i = int.Parse(parts[0]);

                int j = int.Parse(parts[1]);

​

                if (i - 1 < 0 || farm[i - 1][j] != regionLetter) perimeter++;

                if (i + 1 >= farm.Length || farm[i + 1][j] != regionLetter) perimeter++;

                if (j - 1 < 0 || farm[i][j - 1] != regionLetter) perimeter++;

                if (j + 1 >= farm.Length || farm[i][j + 1] != regionLetter) perimeter++;

            }

​

            totalCost += area * perimeter;

        }

​

        return totalCost;

    }

​

    static void Main(string[] args)

    {

        string inputFarm = "[A,A,A,B||C,A,B,B||C,C,D,D||D,D,D,D]";

        int cost = totalCost(inputFarm);

        Console.WriteLine($"Total cost of the farm: {cost}");

    }

}

​