tic tac toe board

using System.Collections.Generic;

namespace tic_tac_toe
{

    class TicTacToeBoard : GameBoard
    {
        public TicTacToeBoard()
        {
            squares = new Player[3, 3] { { 0, 0, 0 }, { 0, 0, 0 }, { 0, 0, 0 } };
        }

        public override int Size { get { return 9; } }

        public override Player this[int x, int y]
        {
            get
            {
                return squares[x, y];
            }

            set
            {
                squares[x, y] = value;
            }
        }

        public override bool IsFull
        {
            get
            {
                foreach (Player i in squares)
                    if (i == Player.Open) { return false; }
                return true;
            }
        }

        public override List<Space> OpenSquares
        {
            get
            {
                List<Space> openSquares = new List<Space>();

                for (int x = 0; x <= 2; x++)
                    for (int y = 0; y <= 2; y++)
                        if (squares[x, y] == Player.Open)
                            openSquares.Add(new Space(x, y));

                return openSquares;
            }
        }

        public override Player Winner
        {
            get
            {
                int count = 0;


                for (int x = 0; x < 3; x++)
                {
                    count = 0;

                    for (int y = 0; y < 3; y++)
                        count += (int)squares[x, y];

                    if (count == 3)
                        return Player.X;
                    if (count == -3)
                        return Player.O;
                }


                for (int x = 0; x < 3; x++)
                {
                    count = 0;

                    for (int y = 0; y < 3; y++)
                        count += (int)squares[y, x];

                    if (count == 3)
                        return Player.X;
                    if (count == -3)
                        return Player.O;
                }


                count = 0;
                count += (int)squares[0, 0];
                count += (int)squares[1, 1];
                count += (int)squares[2, 2];
                if (count == 3)
                    return Player.X;
                if (count == -3)
                    return Player.O;


                count = 0;
                count += (int)squares[0, 2];
                count += (int)squares[1, 1];
                count += (int)squares[2, 0];
                if (count == 3)
                    return Player.X;
                if (count == -3)
                    return Player.O;

                return Player.Open;
            }
        }

        public override GameBoard Clone()
        {
            GameBoard b = new TicTacToeBoard();
            b.squares = (Player[,])this.squares.Clone();
            return b;
        }
    }
}