static public int[][] minimax(int layers, Chessboard board, int player)
{
if (layers == 0)
{
int[][] highScoreArr = new int[2][];
highScoreArr[0] = new int[2] {
board.evaluateBoard(), 0
};
highScoreArr[1] = new int[2] {
0, 0
};
// Console.WriteLine("Final board score: " + highScoreArr[0][0]);
return(highScoreArr);
}
else
{
Dictionary <int[], List <int[]> > moves = board.getLegalMoves(player, true);
int score = 0;
bool firstRun = true;
int highScore = 0;
int[] bestMoveTo = { 0, 0 };
int[] bestMoveFrom = { 0, 0 };
foreach (KeyValuePair <int[], List <int[]> > moveSet in moves)
{
foreach (int[] move in moveSet.Value)
{
Chessboard newBoard = Chessboard.DeepCopy(board);
newBoard.stringMakeMove(moveToText(moveSet.Key, move), player);
if (firstRun)
{
score = minimax(layers - 1, newBoard, -player)[0][0];
highScore = score;
bestMoveFrom = moveSet.Key;
bestMoveTo = move;
firstRun = false;
}
else
{
score = minimax(layers - 1, newBoard, -player)[0][0];
}
if ((score > highScore && player == 1) || (score < highScore && player == -1))
{
// Console.WriteLine("Sick move found");
highScore = score;
bestMoveFrom = moveSet.Key;
bestMoveTo = move;
}
}
}
int[][] highScoreArr = new int[3][];
highScoreArr[0] = new int[2] {
highScore, 0
};
highScoreArr[1] = bestMoveFrom;
highScoreArr[2] = bestMoveTo;
// if (layers == 2) { Console.WriteLine("Best move is " + bestMoveFrom[0] + ":" + bestMoveFrom[1] + " -> " + bestMoveTo[0] + ":" + bestMoveTo[1]); }
if (layers == 2)
{
Console.Write(".");
}
return(highScoreArr);
}
}
public Dictionary <int[], List <int[]> > getLegalMoves(int player, bool checkKing)
{
Dictionary <int[], List <int[]> > legalMoves = new Dictionary <int[], List <int[]> >(new MyEqualityComparer());
bool possible;
int count;
int[] currentKingPosition = { 0, 0 };
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
if (board[i, j] != null && Math.Sign(board[i, j].id) == player)
{
legalMoves[new int[] { i, j }] = new List <int[]>();
Piece currentPiece = board[i, j];
switch (currentPiece.id)
{
case 1: // White Pawn
if (i < 7 && board[i + 1, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j });
}
if (i == 1 && board[i + 1, j] == null && board[i + 2, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 2, j });
}
if (j > 0 && i < 7 && board[i + 1, j - 1] != null && Math.Sign(board[i + 1, j - 1].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j - 1 });
}
if (j < 7 && i < 7 && board[i + 1, j + 1] != null && Math.Sign(board[i + 1, j + 1].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j + 1 });
}
break;
case -1:
if (i > 0 && board[i - 1, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j });
}
if (i == 6 && board[i - 1, j] == null && board[i - 2, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 2, j });
}
if (j > 0 && i > 0 && board[i - 1, j - 1] != null && Math.Sign(board[i - 1, j - 1].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j - 1 });
}
if (j < 7 && i > 0 && board[i - 1, j + 1] != null && Math.Sign(board[i - 1, j + 1].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j + 1 });
}
break;
case 2: // Knight
case -2:
if (i < 6)
{
if (j < 7 && (board[i + 2, j + 1] == null || Math.Sign(board[i + 2, j + 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 2, j + 1 });
}
if (j > 0 && (board[i + 2, j - 1] == null || Math.Sign(board[i + 2, j - 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 2, j - 1 });
}
}
if (i > 1)
{
if (j < 7 && (board[i - 2, j + 1] == null || Math.Sign(board[i - 2, j + 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 2, j + 1 });
}
if (j > 0 && (board[i - 2, j - 1] == null || Math.Sign(board[i - 2, j - 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 2, j - 1 });
}
}
if (j < 6)
{
if (i < 7 && (board[i + 1, j + 2] == null || Math.Sign(board[i + 1, j + 2].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j + 2 });
}
if (i > 0 && (board[i - 1, j + 2] == null || Math.Sign(board[i - 1, j + 2].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j + 2 });
}
}
if (j > 1)
{
if (i < 7 && (board[i + 1, j - 2] == null || Math.Sign(board[i + 1, j - 2].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j - 2 });
}
if (i > 0 && (board[i - 1, j - 2] == null || Math.Sign(board[i - 1, j - 2].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j - 2 });
}
}
break;
case 3: // Bishop
case -3:
possible = true;
count = 1;
while (possible && i + count < 8 && j + count < 8)
{
if (board[i + count, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
else
{
if (Math.Sign(board[i + count, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && i + count >= 0 && j + count >= 0)
{
if (board[i + count, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
else
{
if (Math.Sign(board[i + count, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
possible = false;
}
count--;
}
possible = true;
count = 1;
while (possible && i + count < 8 && j - count >= 0)
{
if (board[i + count, j - count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
else
{
if (Math.Sign(board[i + count, j - count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && i + count >= 0 && j - count < 8)
{
if (board[i + count, j - count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
else
{
if (Math.Sign(board[i + count, j - count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
possible = false;
}
count--;
}
break;
case 4: // Rook
case -4:
possible = true;
count = 1;
while (possible && i + count < 8)
{
if (board[i + count, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
else
{
if (Math.Sign(board[i + count, j].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && i + count >= 0)
{
if (board[i + count, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
else
{
if (Math.Sign(board[i + count, j].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
possible = false;
}
count--;
}
possible = true;
count = 1;
while (possible && j + count < 8)
{
if (board[i, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
else
{
if (Math.Sign(board[i, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && j + count >= 0)
{
if (board[i, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
else
{
if (Math.Sign(board[i, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
possible = false;
}
count--;
}
break;
case 5: // Queen
case -5:
possible = true;
count = 1;
while (possible && i + count < 8 && j + count < 8)
{
if (board[i + count, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
else
{
if (Math.Sign(board[i + count, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && i + count >= 0 && j + count >= 0)
{
if (board[i + count, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
else
{
if (Math.Sign(board[i + count, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j + count });
}
possible = false;
}
count--;
}
possible = true;
count = 1;
while (possible && i + count < 8 && j - count >= 0)
{
if (board[i + count, j - count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
else
{
if (Math.Sign(board[i + count, j - count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && i + count >= 0 && j - count < 8)
{
if (board[i + count, j - count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
else
{
if (Math.Sign(board[i + count, j - count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j - count });
}
possible = false;
}
count--;
}
possible = true;
count = 1;
while (possible && i + count < 8)
{
if (board[i + count, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
else
{
if (Math.Sign(board[i + count, j].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && i + count >= 0)
{
if (board[i + count, j] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
else
{
if (Math.Sign(board[i + count, j].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i + count, j });
}
possible = false;
}
count--;
}
possible = true;
count = 1;
while (possible && j + count < 8)
{
if (board[i, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
else
{
if (Math.Sign(board[i, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
possible = false;
}
count++;
}
possible = true;
count = -1;
while (possible && j + count >= 0)
{
if (board[i, j + count] == null)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
else
{
if (Math.Sign(board[i, j + count].id) != player)
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + count });
}
possible = false;
}
count--;
}
break;
case 6: // King
case -6:
if (i < 7 && (board[i + 1, j] == null || Math.Sign(board[i + 1, j].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j });
}
if (i < 7 && j < 7 && (board[i + 1, j + 1] == null || Math.Sign(board[i + 1, j + 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j + 1 });
}
if (j < 7 && (board[i, j + 1] == null || Math.Sign(board[i, j + 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j + 1 });
}
if (i > 0 && j < 7 && (board[i - 1, j + 1] == null || Math.Sign(board[i - 1, j + 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j + 1 });
}
if (i > 0 && (board[i - 1, j] == null || Math.Sign(board[i - 1, j].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j });
}
if (i > 0 && j > 0 && (board[i - 1, j - 1] == null || Math.Sign(board[i - 1, j - 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i - 1, j - 1 });
}
if (j > 0 && (board[i, j - 1] == null || Math.Sign(board[i, j - 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i, j - 1 });
}
if (i < 7 && j > 0 && (board[i + 1, j - 1] == null || Math.Sign(board[i + 1, j - 1].id) != player))
{
legalMoves[new int[] { i, j }].Add(new int[] { i + 1, j - 1 });
}
if (Math.Sign(board[i, j].id) == player)
{
currentKingPosition = new int[] { i, j };
}
break;
}
}
}
}
if (checkKing)
{
Dictionary <int[], List <int> > movesToRemove = new Dictionary <int[], List <int> >();
foreach (KeyValuePair <int[], List <int[]> > legalMoveSet in legalMoves)
{
int i = 0;
foreach (int[] legalMove in legalMoveSet.Value)
{
Chessboard nextMove = DeepCopy(this);
nextMove.stringMakeMove(moveToText(legalMoveSet.Key, legalMove), player);
if (legalMove[0] == 6 && legalMove[1] == 4)
{
// nextMove.displayBoard(1);
}
Dictionary <int[], List <int[]> > tempLegalMoves = nextMove.getLegalMoves(player * -1, false);
foreach (KeyValuePair <int[], List <int[]> > tempLegalMoveSet in tempLegalMoves)
{
foreach (int[] tempMove in tempLegalMoveSet.Value)
{
if (nextMove.board[tempMove[0], tempMove[1]] != null && nextMove.board[tempMove[0], tempMove[1]].id == player * 6)
{
// Console.WriteLine("Removed a bad move!" + legalMoveSet.Key[0] + legalMoveSet.Key[1] + "-" + legalMoveSet.Value[i][0] + legalMoveSet.Value[i][1]);
try {
movesToRemove[legalMoveSet.Key].Add(i);
} catch {
movesToRemove[legalMoveSet.Key] = new List <int>();
movesToRemove[legalMoveSet.Key].Add(i);
}
// legalMoves[legalMoveSet.Key].RemoveAt(i);
// break;
}
}
}
i++;
}
}
foreach (KeyValuePair <int[], List <int> > moveToRemove in movesToRemove)
{
List <int> alreadyRemoved = new List <int>();
foreach (int i in moveToRemove.Value.AsEnumerable().Reverse())
{
// Console.WriteLine("We are going to remove the move for " + moveToRemove.Key[0] + moveToRemove.Key[1] + " at index " + i);
if (!alreadyRemoved.Contains(i))
{
try {
legalMoves[moveToRemove.Key].RemoveAt(i);
} catch { }
alreadyRemoved.Add(i);
}
}
}
}
return(legalMoves);
}