public Node(Move move, Node parent, State state, Deck deck)
{
this.state = state;
this.generatingMove = move;
this.parent = parent;
this.results = 0;
this.visits = 0;
this.children = new List<Node>();
this.untriedMoves = state.GetMoves(deck);
}
// adds a child node to the list of children
// after exploring a move - removes the move from untried
public Node AddChild(Move move, State state, Deck deck)
{
Node child = new Node(move, this, state, deck);
this.untriedMoves.Remove(move);
this.children.Add(child);
return child;
}
// Time limited MCTS
private Node TimeLimited(State rootState, int timeLimit, Stopwatch timer, Deck deck)
{
Node rootNode = new Node(null, null, rootState, deck);
while (true)
{
if (timer.ElapsedMilliseconds > timeLimit)
{
if (FindBestChild(rootNode.Children) == null && !rootNode.state.IsGameOver())
{
timeLimit += 10;
timer.Restart();
}
else
{
return rootNode;
}
}
Node node = rootNode;
State state = rootState.Clone();
Deck clonedDeck = deck.Clone();
// 1: Select
while (node.UntriedMoves.Count == 0 && node.Children.Count != 0)
{
node = node.SelectChild();
state = state.ApplyMove(node.GeneratingMove);
if (node.GeneratingMove is ComputerMove)
{
clonedDeck.Remove(((ComputerMove)node.GeneratingMove).Card);
if (clonedDeck.IsEmpty()) clonedDeck = new Deck();
}
}
// 2: Expand
if (node.UntriedMoves.Count != 0)
{
Move randomMove = node.UntriedMoves[random.Next(0, node.UntriedMoves.Count)];
if (randomMove is ComputerMove)
{
if (clonedDeck.IsEmpty()) clonedDeck = new Deck();
clonedDeck.Remove(((ComputerMove)randomMove).Card);
state = state.ApplyMove(randomMove);
node = node.AddChild(randomMove, state, clonedDeck);
}
else
{
state = state.ApplyMove(randomMove);
node = node.AddChild(randomMove, state, clonedDeck);
}
}
// 3: Simulation
while (state.GetMoves(clonedDeck).Count != 0)
{
Move move = state.GetRandomMove(clonedDeck);
if (move is ComputerMove)
{
if (clonedDeck.IsEmpty()) clonedDeck = new Deck();
clonedDeck.Remove(((ComputerMove)move).Card);
state = state.ApplyMove(move);
}
else
{
state = state.ApplyMove(move);
}
}
// 4: Backpropagation
while (node != null)
{
node.Update(state.GetResult());
node = node.Parent;
}
}
}