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

namespace Assignment_2___Question_4{
    class Program{
        static void Main(string[] args){
            int[,] line = { { 6, 3, 4, 9, 1, 5, 7, 2, 8 }, { 2, 7, 8, 6, 4, 3, 5, 1, 9 }, { 5, 9, 1, 2, 7, 8, 6, 4, 3 }, { 4, 5, 7, 3, 6, 9, 2, 8, 1 }, { 9, 8, 6, 4, 2, 1, 3, 5, 7 }, { 3, 1, 2, 8, 5, 7, 4, 9, 6 }, { 1, 2, 5, 7, 8, 6, 9, 3, 4 }, { 8, 6, 3, 5, 9, 4, 1, 7, 2 }, { 7, 4, 9, 1, 3, 2, 8, 6, 5 } };
            Console.WriteLine("---------------------------------------");
            for (int i = 0; i < 9; i++){
                for (int j = 0; j < 9; j++){
                    Console.Write(" | "+line[i,j]);
                }
                Console.WriteLine(" |");
                Console.WriteLine("---------------------------------------");
            }
            if (CheckAllLines(line) && CheckAllColls(line) && CheckAllBlocks(line)){
                Console.WriteLine("This solution is correct!");
            }else{
                Console.WriteLine("This solution is wrong!");
            }
            Console.ReadKey();
        }

        public static bool LineCorrectness(int[] lineArray, int count = 0){
            return count > 8 || (!lineArray.Skip(count+1).Contains(lineArray[count]) && LineCorrectness(lineArray, count+1));
        }

        public static bool CheckAllLines(int[,] arrayOfLines, int count = 0){
            if(count < 9){
                int[] row = new int[9];
                for (int i = 0; i < 9; i++){
                    row[i] = arrayOfLines[count,i];
                }
                return LineCorrectness(row) && CheckAllLines(arrayOfLines, count+1);
            }
            return true;
        }

        public static bool CheckAllColls(int[,] arrayOfLines, int count = 0){
            if(count < 9){
                int[] row = new int[9];
                for (int i = 0; i < 9; i++){
                    row[i] = arrayOfLines[i, count];
                }
                return LineCorrectness(row) && CheckAllColls(arrayOfLines, count + 1);
            }
            return true;
        }
        public static bool CheckAllBlocks(int[,] arrayOfLines, int count = 0){
            if(count < 9){
                int rowPos = 0;
                int[] row = new int[9];
                for (int i = (count%3)*3; i < ((count % 3) * 3)+3; i++){
                    double val = count / 3;
                    for (int k = ((int)Math.Floor(val)*3); k < ((int)Math.Floor(val) * 3)+3; k++) {
                        row[rowPos] = arrayOfLines[i, k];
                        rowPos++;
                    }
                }
                return LineCorrectness(row) && CheckAllBlocks(arrayOfLines, count + 1);
            }
            return true;
        }
    }
}