using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace sudoku
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //byte[,] plocha = new byte[9, 9];
            byte aktivniKelii = 0;
            string vlez;
            bool aktivnost = true, validenVlez = false;

            /*fillPlocha(plocha);*/
            byte[,] plocha = new byte[,]{
                    {0, 2, 5, 0, 0, 1, 0, 0, 0},
                    {1, 0, 4, 2, 5, 0, 0, 0, 0},
                    {0, 5, 0, 0, 0, 0, 3, 2, 0},
                    {6, 0, 0, 0, 2, 0, 0, 0, 9},
                    {0, 8, 7, 0, 0, 0, 0, 6, 0},
                    {0, 9, 1, 5, 0, 6, 6, 0, 0},
                    {0, 9, 1, 5, 0, 0, 6, 0, 0},
                    {0, 0, 0, 0, 7, 8, 1, 0, 3},
                    {0, 0, 0, 6, 0, 0, 5, 9, 0},
                    };

            solve(plocha);
            /*while (aktivnost)
            {
                Console.WriteLine("Vnesi komanda (-iskluchi, -prikazhi, -vmetni, -reshi):\r\n");
                vlez = Console.ReadLine();
                switch (vlez)
                {
                    case "-reshi":
                        {
                            for (byte x = 0; x < 9; x++)
                            {
                                for (byte y = 0; y < 9; y++)
                                {
                                    if (plocha[x, y] != 0) aktivniKelii++;
                                    if (aktivniKelii > 17)
                                    {
                                        validenVlez = true;
                                        break;
                                    }
                                }
                            }
                            if (!validenVlez)
                            {
                                Console.WriteLine("\r\nVmetni barem 17 vrednosti. Obidi se povtorno!\r\n");
                                break;
                            }

                            solve(plocha);

                            break;
                        }
                    case "-prikazhi":
                        {
                            Console.WriteLine();
                            for (byte x = 0; x < 9; x++)
                            {
                                for (byte y = 0; y < 9; y++)
                                {
                                    if (y == 8)
                                    {
                                        Console.WriteLine(plocha[x, y]);
                                        continue;
                                    }
                                    Console.Write(plocha[x, y] + " ");
                                }
                            }
                            Console.WriteLine();
                            break;
                        }
                    case "-vmetni":
                        {
                            Console.WriteLine("\r\nVnesi pozicija i vrednost (x y vrednost):\r\n");
                            string baferVlez = Console.ReadLine();
                            plocha[Byte.Parse(baferVlez[0].ToString()), Byte.Parse(baferVlez[2].ToString())] = Byte.Parse(baferVlez[4].ToString());
                            Console.WriteLine("\r\nVmetnato.\r\n");
                            break;
                        }
                    case "-iskluchi":
                        {
                            aktivnost = false;
                            Console.WriteLine("\r\nAdios.");
                            break;
                        }
                    default:
                        {
                            Console.Write("\r\nNevalidna komanda! ");
                            break;
                        }
                }
            }
            */
        }

        private static void solve(byte[,] plocha)
        {

            Console.WriteLine("Solving...");
            List<List<int>> validSet = new List<List<int>>();
            List<int> validRow = new List<int>();
            List<int> validCol = new List<int>();
            List<int> validBox = new List<int>();

            for (int i = 0; i < 9; i++)
            {
                for (int j = 0; j < 9; j++)
                {
                    int[] currRow = new int[9];
                    int[] currCol = new int[9];
                    int[] currBox = new int[9];
                    int k = 0;
                    //currRow
                    for (int cntJ=0; cntJ<9; cntJ++)
                    {
                        if(plocha[i,cntJ] != 0)
                            currRow[k] = plocha[i, cntJ];

                        k++;
                    }
                    Console.WriteLine("currRow filled");
                    //currCol
                    k = 0;
                    for (int cntI = 0; cntI < 9; cntI++)
                    {
                        if (plocha[cntI, j] != 0)
                            currCol[k] = plocha[cntI, j];

                        k++;
                    }
                    Console.WriteLine("currCol filled");
                    //currBox
                    int regSize = 3;
                    int subBoxI = i / regSize;
                    int subBoxJ = j / regSize;
                    int offsetI = regSize * subBoxI;
                    int offsetJ = regSize * subBoxJ;
                    k = 0;
                    for (int r = 0; r < 3; r++)
                    {
                        for(int c = 0; c < 3; c++)
                        {
                            if (plocha[offsetI + r, offsetJ + c] != 0)
                                currBox[k] = plocha[offsetI + r, offsetJ + c];

                            k++;
                        }
                    }

                    Console.WriteLine("currBox filled");
                    if (plocha[i,j] == 0)
                    {
                        for (int r = 1; r < 10; r++)
                        {
                            if (!currRow.Contains(r))
                                validRow.Add(r);
                            if (!currCol.Contains(r))
                                validCol.Add(r);
                            if (!currBox.Contains(r))
                                validBox.Add(r);
                            Console.WriteLine("Valid sets filled");
                        }

                        List<int> temp = new List<int>();

                        for (int r = 1; r < 10; r++)
                        {
                            if (validRow.Contains(r) && validCol.Contains(r) && validBox.Contains(r))
                            {
                                temp = new List<int>();
                                temp.Add(r);
                            }
                        }
                        Console.WriteLine("Final valid set filled..");
                        validSet.Add(temp);
                    }
                }
            }

            Console.WriteLine(validSet);
        }
        private static void fillPlocha(byte[,] plocha)
        {
            for (byte x = 0; x < 9; x++)
            {
                for (byte y = 0; y < 9; y++)
                {
                    plocha[x, y] = 0;
                }
            }
        }
    }
}