public static List<Node> GenerateSuccessors(Board board, bool isBlack)
{
//Validate moves based on current state to generate new states
var nodes = new List<Node>();
//Generate # of valid moves
var ValidMoves = GetNumberOfMoves(board);
//Foreach valid move, generate a new node (evaluated in minimax)
for (var i = 0; i < ValidMoves.Length; i++)
{
if (ValidMoves[i])
{
var tempBoard = new Board(board.State);
//Make the move
tempBoard.AddToBoard(i, isBlack);
//Create a Node
var node = new Node();
node.Board = tempBoard;
nodes.Add(node);
}
}
return nodes;
}
public int Search(Node node, int depth, bool maxPlayer)
{
if (depth == 0 || node.IsTerminalNode())
{
return Utility.Score(node);
}
if (maxPlayer)
{
int bestValue = Int32.MinValue;
node.Children = Utility.GenerateSuccessors(node.Board, false);
for (var i = 0; i < node.Children.Count; i++)
{
var currentValue = Search(node.Children[i], depth - 1, false);
bestValue = Math.Max(bestValue, currentValue);
}
return bestValue;
}
else
{
int bestValue = Int32.MaxValue;
node.Children = Utility.GenerateSuccessors(node.Board, true);
for (var i = 0; i < node.Children.Count; i++)
{
var currentValue = Search(node.Children[i], depth - 1, true);
bestValue = Math.Max(bestValue, currentValue);
}
return bestValue;
}
}
//This method will search all the columns and return the best move for the AI to make.
//Will run AlphaBeta or regular Minimax depending on user selection.
public static int AiHelperMove(Board board, bool alphabeta, int depth)
{
var rows = board.State.GetLength(1) - 1;
int bestValue = Int32.MinValue;
int bestColumn = -1;
if (alphabeta)
{
MiniMaxAb miniMaxAb = new MiniMaxAb();
for (var i = 0; i <= rows; i++)
{
var node = new Node();
var tempBoard = new Board(board.State);
if (tempBoard.ValidateMove(i))
{
tempBoard.AddToBoard(i, true);
node.Board = tempBoard;
var currentValue = miniMaxAb.Search(node, depth, Int32.MinValue, Int32.MaxValue, false);
if (currentValue >= bestValue)
{
bestValue = currentValue;
bestColumn = i;
}
}
}
}
else
{
MiniMax miniMax = new MiniMax();
for (var i = 0; i <= rows; i++)
{
var node = new Node();
var tempBoard = new Board(board.State);
if (tempBoard.ValidateMove(i))
{
tempBoard.AddToBoard(i, true);
node.Board = tempBoard;
var currentValue = miniMax.Search(node, depth, false);
if (currentValue >= bestValue)
{
bestValue = currentValue;
bestColumn = i;
}
}
}
}
return bestColumn;
}
//Search with alpha beta pruning
public int Search(Node node, int depth, int alpha, int beta, bool maxPlayer)
{
if (depth == 0 || node.IsTerminalNode())
{
return Utility.Score(node);
}
if (maxPlayer)
{
int bestValue = Int32.MinValue;
node.Children = Utility.GenerateSuccessors(node.Board, false);
for (var i = 0; i < node.Children.Count; i++)
{
bestValue = Math.Max(bestValue, Search(node.Children[i], depth - 1, alpha, beta, false));
alpha = Math.Max(bestValue, bestValue);
if (beta <= alpha)
{
break;
}
}
return alpha;
}
else
{
int bestValue = Int32.MaxValue;
node.Children = Utility.GenerateSuccessors(node.Board, true);
for (var i = 0; i < node.Children.Count; i++)
{
bestValue = Math.Min(bestValue, Search(node.Children[i], depth - 1, alpha, beta, true));
beta = Math.Min(beta, bestValue);
if (beta <= alpha)
{
break;
}
}
return beta;
}
}
//Same as above, except it returns a Tuple with both Black and White scores.
public static Tuple<int, int> FinalScore(Node node)
{
var row = node.Board.State.GetLength(0);
var col = node.Board.State.GetLength(1);
var BlackScore = 0;
var WhiteScore = 0;
node.Board.ResetVisited();
//Console.WriteLine("\n");
//Console.WriteLine("Scoring The following Board");
//node.Board.PrintState();
for (var i = 0; i < row; i++)
{
for (var j = 0; j < col; j++)
{
//Get first piece found
if (node.Board.State[i, j] != null)
{
var piece = node.Board.State[i, j];
//Get list of Adjacent pieces
var adjacentPieces = GetAdjacentPieces(piece, node.Board);
//Compare piece to each adj piece, if its diag/or not, and add up score
foreach (var tuple in adjacentPieces)
{
//If piece has been visited or is another color, skip it.
if (tuple.Item2 != null && !tuple.Item2.Visited)
{
if (tuple.Item1) //if true, its a diagonal score
{
if (piece.IsBlack && tuple.Item2.IsBlack)
{
BlackScore++;
piece.Visited = true;
}
else if (!piece.IsBlack && !tuple.Item2.IsBlack)
{
WhiteScore++;
piece.Visited = true;
}
}
else //Its a normal position worth 2 points
{
if (piece.IsBlack && tuple.Item2.IsBlack)
{
BlackScore += 2;
piece.Visited = true;
}
else if (!piece.IsBlack && !tuple.Item2.IsBlack)
{
WhiteScore += 2;
piece.Visited = true;
}
}
}
}
}
}
}
return Tuple.Create(WhiteScore, BlackScore);
}
static void Main(string[] args)
{
//Following is setup for AI and board
Console.WriteLine("Welcome to Simacogo! You are Player 1, Color white.");
Console.WriteLine("At any time, type 'exit' to leave the game!");
Console.WriteLine("----------------------------------------------------------");
Console.WriteLine("\n");
Console.WriteLine("Enter # of plies for AI to search to? (numeric only)");
var depth = Int32.Parse(Console.ReadLine()); //AI lookahead value
Console.WriteLine("\n");
Console.WriteLine("Enable Alpha Beta Pruning? (True or False)");
var alphabeta = Boolean.Parse(Console.ReadLine()); //AI lookahead value
Console.WriteLine("\n");
Console.WriteLine("Enter board width? (numeric only)");
var width = Int32.Parse(Console.ReadLine()); //Board width
Console.WriteLine("Enter board height? (numeric only)");
var height = Int32.Parse(Console.ReadLine()); //Board height
Console.WriteLine("\n");
Board board = new Board(width, height);
bool humanTurn = true;
bool runProgram = true;
while (!board.IsFull() && runProgram)
{
if (humanTurn)
{
Console.WriteLine("--------------------Begin Human Turn-----------------------------------");
Console.WriteLine("Please type the column you want to drop a piece into and press enter. (1-9)");
string enteredValue = Console.ReadLine();
if (enteredValue.Equals("exit"))
{
runProgram = false;
break;
}
int colValue = Int32.MinValue;
Int32.TryParse(enteredValue, out colValue);
if (colValue > 0 && colValue < 10 && board.ValidateMove(colValue-1))
{
//Get column from User && Create new piece and enter it in the board at deepest possible position in column.
board.AddToBoard(colValue-1, false);
board.PrintState();
var node = new Node();
node.Board = board;
var score = Utility.FinalScore(node);
Console.WriteLine("\n");
Console.WriteLine("Current Score: \n");
Console.WriteLine("Human: " + score.Item1);
Console.WriteLine("AI " + score.Item2);
Console.WriteLine("--------------------End Human Turn----------------------");
Console.WriteLine("\n");
humanTurn = !humanTurn;
}
else
{
Console.WriteLine("Invalid selection, please try again.");
}
}
else
{
Console.WriteLine("--------------------Begin AI Turn--------------------");
//Let AI player pick position
//Update Board
//AI Runs either Miniax or MinimaxAB depending on user selection.
var bestMove = Utility.AiHelperMove(board, alphabeta, depth);
board.AddToBoard(bestMove, true);
board.PrintState();
var node = new Node();
node.Board = board;
var score = Utility.FinalScore(node);
Console.WriteLine("\n");
Console.WriteLine("Current Score: \n");
Console.WriteLine("Human: " + score.Item1);
Console.WriteLine("AI " + score.Item2);
Console.WriteLine("\n");
Console.WriteLine("--------------------End AI Turn----------------------");
humanTurn = !humanTurn;
}
}
Console.WriteLine("\n");
Console.WriteLine("Gameboard is Full!");
Console.WriteLine("\n");
var finalNode = new Node();
var tempBoard = new Board(board.State);
finalNode.Board = tempBoard;
var finalScore = Utility.FinalScore(finalNode);
Console.WriteLine("Final Board");
Console.WriteLine("\n");
board.PrintState();
Console.WriteLine("\n");
Console.WriteLine("Final Score Is: ");
Console.WriteLine("Human: " + finalScore.Item1);
Console.WriteLine("AI: " + finalScore.Item2);
Console.WriteLine("Thank you for playing Simacogo! Application will close in 5 seconds.");
System.Threading.Thread.Sleep(5000);
}
