public Move getBestMove(Desk desk, GameRules rules) { movesInspected = 0; int topMoveScore = int.MinValue; int currentScore = 0; short currentPlayer = desk.getCurrentPlayer(); short oppositePlayer = rules.getOppositePlayer(currentPlayer); bool maximizingPlayer = false; ArrayList topMoves = new ArrayList(); //check game end - both players have some fields and at least one can move if (rules.isGameEnd(desk)) { return(null); } ArrayList possiblePlayerMoves = rules.getPossibleMoves(desk, currentPlayer); if (possiblePlayerMoves.Count == 0) //no possible moves for current player, switch to another player { possiblePlayerMoves = rules.getPossibleMoves(desk, oppositePlayer); oppositePlayer = currentPlayer; maximizingPlayer = !maximizingPlayer; } //loop possible moves foreach (Move move in possiblePlayerMoves) { //try the move and run minimax desk.makeMove(move); currentScore = minimax(desk, rules, depthMax, oppositePlayer, maximizingPlayer); desk.undoMove(move); if (currentScore > topMoveScore) //new top move found { topMoveScore = currentScore; topMoves.Clear(); topMoves.Add(move); } else if (currentScore == topMoveScore) //more moves with same value found { topMoves.Add(move); } } if (!randomMoveSelection) { return((Move)topMoves[0]); } //pick randomly one of the top moves Random r = new Random(); return((Move)topMoves[r.Next(0, topMoves.Count)]); }
private void handlePieceClick(Object sender, EventArgs e) { if (!pieceClickListening) { return; } bool setAIButtons = false; cancelAIComputing(setAIButtons); // AI computing "show best move" could be in progress PictureBox pieceClicked = (PictureBox)sender; int[] coords = Coords.getPieceCoordsFromName(pieceClicked.Name); if (isPieceSelectError) { tableDesk.Refresh(); isPieceSelected = false; isPieceSelectError = false; } if (wasClickedOnOwnPiece(desk.getCurrentPlayer(), coords)) // start piece of move { // clean previously highlighted pieces tableDesk.Refresh(); piecesSelected.Clear(); pieceFocused = pieceClicked; isPieceSelected = true; if (showPossibleMoves) { highlightPossibleMovesFromPiece(pieceFocused, piecesSelected); } else { drawPictureBoxControl(pieceClicked, Properties.Resources.piece_control_select); } } else if (isPieceSelected) // following pieces of move { if (isPartialMove(pieceFocused, pieceClicked, piecesSelected)) // move cannot be made yet, clicked piece is not end piece { piecesSelected.Add(pieceClicked); if (showPossibleMoves) { highlightPossibleMovesFromPiece(pieceFocused, piecesSelected); } else { drawPictureBoxControl(pieceClicked, Properties.Resources.piece_control_select); } return; } try { makeHumanMove(pieceFocused, pieceClicked, piecesSelected); } catch // selected move isn't possible { bool cleanOutput = true; ArrayList possibleMoves = rules.getPossibleMoves(desk, desk.getCurrentPlayer()); Random r = new Random(); Move randomMove = (Move)possibleMoves[r.Next(0, possibleMoves.Count)]; drawPictureBoxControl(pieceClicked, Properties.Resources.piece_control_error); addGameNotice("you could play for example " + Coords.getCoordsStr(randomMove), cleanOutput); addGameNotice("move " + Coords.getCoordsStr(pieceFocused) + " " + Coords.getCoordsStr(pieceClicked) + " is not possible"); } isPieceSelectError = true; } else // clicked on some piece without possibility of making move { tableDesk.Refresh(); isPieceSelected = false; } }
private int minimax(Desk desk, GameRules rules, int depth, short currentPlayer, bool maximizingPlayer) { movesInspected++; short oppositePlayer = rules.getOppositePlayer(currentPlayer); if (rules.isGameEnd(desk)) //check game end - both players have some fields and at least one can move { short nextPlayer = rules.getNextPlayer(desk); if (desk.getPlayerFields(GameVar.PLAYER_WHITE).Count != 0 && desk.getPlayerFields(GameVar.PLAYER_BLACK).Count != 0 && nextPlayer == -1) { return(0); //draw, neither of players can move } if (maximizingPlayer) { return(int.MinValue + depthMax - depth); } return(int.MaxValue - depthMax + depth); } if (depth == 0) //check depth level, return eval of current position { if (maximizingPlayer) { return(-rules.getGameEvaluation(desk, oppositePlayer)); } return(rules.getGameEvaluation(desk, oppositePlayer)); } //get new possible moves, make the moves and call recursively minmax ArrayList possibleMoves = rules.getPossibleMoves(desk, currentPlayer); int bestVal = 0; int currentVal = 0; //current player has no possible moves, play "nothing" and call minimax if (possibleMoves.Count == 0) { if (maximizingPlayer) { bestVal = int.MinValue; currentVal = minimax(desk, rules, depth, oppositePlayer, false); bestVal = Math.Max(bestVal, currentVal); } else { bestVal = int.MaxValue; currentVal = minimax(desk, rules, depth, oppositePlayer, true); bestVal = Math.Min(bestVal, currentVal); } return(bestVal); } if (maximizingPlayer) //current player's best move, looking for the highest rating move { bestVal = int.MinValue; foreach (Move move in possibleMoves) { desk.makeMove(move); currentVal = minimax(desk, rules, depth - 1, oppositePlayer, false); desk.undoMove(move); bestVal = Math.Max(bestVal, currentVal); } } else //opposite player's best move - the worst move for current player, looking for the lowest rating move { bestVal = int.MaxValue; foreach (Move move in possibleMoves) { desk.makeMove(move); currentVal = minimax(desk, rules, depth - 1, oppositePlayer, true); desk.undoMove(move); bestVal = Math.Min(bestVal, currentVal); } } return(bestVal); }