using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var chessBoard = new ChessBoard();

        var queenSetResolver = new QueensSetResolver(chessBoard);

        if (queenSetResolver.SetQueens())

        {

            Console.WriteLine("Result found:");

            Console.WriteLine();

​

            chessBoard.DisplayBoard();

            Console.ReadLine();

        }

        else

        {

            Console.WriteLine("We don't have any result!");

        }

    }

}

​

public class ChessBoard {

    public ChessBoard() {

        Board = new int[8, 8];

    }

    public int[,] Board;

    public void DisplayBoard()

    {

        for(int i = 0; i <= Board.GetUpperBound(0); i++)

        {

            for(int j = 0; j <= Board.GetUpperBound(0); j++)

            {

                Console.Write(Board[i,j]);

                Console.Write(" ");

            }

​

            Console.WriteLine();

        }

​

        Console.WriteLine();

    }

    public IEnumerable<int> GetRow(int row)

    {

        for (int i = 0; i <= Board.GetUpperBound(1); ++i)

            yield return Board[row, i];

    }

​

    public IEnumerable<int> GetColumn(int column)

    {

        for (int i = 0; i <= Board.GetUpperBound(0); ++i)

            yield return Board[i, column];

    }

​

    public IEnumerable<int> GetDiagonals(int row, int column)

    {

        for (int i = 0; i <= Board.GetUpperBound(0); i++)

        {

            for (int j = 0; j <= Board.GetUpperBound(1); j++)

            {

                if (Math.Abs(row - i) == Math.Abs(column - j))

                {

                    yield return Board[i, j];

                }

            }

        }

    }

}

​

public class QueensSetResolver {

    private ChessBoard _chessBoard;

    public QueensSetResolver(ChessBoard chessBoard) {

        _chessBoard = chessBoard;

    }

    bool IsValidStep(int row, int column)

    {

        if (_chessBoard.GetRow(row).Cast<int>().Sum() > 0)

        {

            return false;

        }

​

        if (_chessBoard.GetColumn(column).Cast<int>().Sum() > 0)

        {

            return false;

        }

​

        if (_chessBoard.GetDiagonals(row, column).Cast<int>().Sum() > 0)

        {

            return false;

        }

​

        return true;

    }

    bool IsBoardCompleted()

    {

        return _chessBoard.Board.Cast<int>().Sum() == 8;

    }

    public bool SetQueens(int currentRow = 0, int currentColumn = 0)

    {

        int startRow = currentRow;

        int startColumn = currentColumn;

​

        for (int i = startRow; i <= _chessBoard.Board.GetUpperBound(0); i++)

        {

            for (int j = startColumn; j <= _chessBoard.Board.GetUpperBound(1); j++)

            {

                if (_chessBoard.Board[i, j] == 0)

                {

                    if (IsValidStep(i, j))

                    {

                        _chessBoard.Board[i, j] = 1;

​

                        if (IsBoardCompleted())

                        {

                            return true;

                        }

​

                        if (SetQueens(i, j))

                        {

                            return true;

                        }

                    }

                }

            }

​

            startColumn = 0;

        }

​

        if (IsBoardCompleted())

        {

            return true;

        }

​

        _chessBoard.Board[currentRow, currentColumn] = 0;

​

        return false;

    }

}