private Score SimulateLeaf(GameState state)
{
while (!state.IsGameFinished())
{
GameSimulator.Simulate(state, true);
if (state.Turn >= 100)
{
break;
}
}
return(state.CalculateScore());
}
public Node(GameState state)
{
State = state;
for (int i = 0; i < 20; i++)
{
GameState simState = new GameState(State);
while (!simState.IsGameFinished())
{
GameSimulator.Simulate(simState, true);
}
_result.Wins += simState.GetResult() ? 1 : 0;
_result.Games++;
}
}
public void Expand()
{
_visitCount++;
if (_expanded)
{
Node bestChild = null;
double bestUtc = 0;
foreach (Node child in Children.Values)
{
if (child.State.Self == null)
{
continue;
}
double uct = child.Result.WinRate + SQRT_TWO * Math.Sqrt(Math.Log(_visitCount) / child._visitCount);
if (uct > bestUtc)
{
bestChild = child;
bestUtc = uct;
}
}
bestChild?.Expand();
return;
}
foreach (MoveType move in State.GetPossibleMoves())
{
GameState nextGameState = new GameState(State);
nextGameState.ApplyRequestedAction(MoveTypeToRequestedAction(move));
GameSimulator.Simulate(nextGameState, false);
Children.Add(move, new Node(nextGameState));
}
_expanded = true;
}
private (RequestedActions, Score) SimulateBranch(int remainingDepth, GameState state)
{
if (state.IsGameFinished())
{
return(null, state.CalculateScore());
}
Score bestScore = Score.MinValue();
RequestedActions bestAction = null;
if (state.IsPosWalkable(state.Self.Position + new Vector2Int(1, 0)))
{
GameState newState = new GameState(state);
newState.Self.Position += new Vector2Int(1, 0);
GameSimulator.Simulate(newState, false);
Score score;
if (remainingDepth > 0)
{
score = SimulateBranch(remainingDepth - 1, newState).Item2;
}
else
{
score = SimulateLeaf(newState);
}
if (score >= bestScore)
{
bestScore = score;
bestAction = new RequestedActions
{
Move = new Vector2Int(1, 0)
};
}
}
if (state.IsPosWalkable(state.Self.Position + new Vector2Int(-1, 0)))
{
GameState newState = new GameState(state);
newState.Self.Position += new Vector2Int(-1, 0);
GameSimulator.Simulate(newState, false);
Score score;
if (remainingDepth > 0)
{
score = SimulateBranch(remainingDepth - 1, newState).Item2;
}
else
{
score = SimulateLeaf(newState);
}
if (score >= bestScore)
{
bestScore = score;
bestAction = new RequestedActions
{
Move = new Vector2Int(-1, 0)
};
}
}
if (state.IsPosWalkable(state.Self.Position + new Vector2Int(0, 1)))
{
GameState newState = new GameState(state);
newState.Self.Position += new Vector2Int(0, 1);
GameSimulator.Simulate(newState, false);
Score score;
if (remainingDepth > 0)
{
score = SimulateBranch(remainingDepth - 1, newState).Item2;
}
else
{
score = SimulateLeaf(newState);
}
if (score >= bestScore)
{
bestScore = score;
bestAction = new RequestedActions
{
Move = new Vector2Int(0, 1)
};
}
}
if (state.IsPosWalkable(state.Self.Position + new Vector2Int(0, -1)))
{
GameState newState = new GameState(state);
newState.Self.Position += new Vector2Int(0, -1);
GameSimulator.Simulate(newState, false);
Score score;
if (remainingDepth > 0)
{
score = SimulateBranch(remainingDepth - 1, newState).Item2;
}
else
{
score = SimulateLeaf(newState);
}
if (score >= bestScore)
{
bestScore = score;
bestAction = new RequestedActions
{
Move = new Vector2Int(0, -1)
};
}
}
{
GameState newState = new GameState(state);
GameSimulator.Simulate(newState, false);
Score score;
if (remainingDepth > 0)
{
score = SimulateBranch(remainingDepth - 1, newState).Item2;
}
else
{
score = SimulateLeaf(newState);
}
if (score >= bestScore)
{
bestScore = score;
bestAction = new RequestedActions();
}
}
if (state.Self.Bomb == null)
{
GameState newState = new GameState(state)
{
Self = { Bomb = new BombState(state.Self.BombFuze, state.Self.BombRadius, state.Self.Position) }
};
GameSimulator.Simulate(newState, false);
Score score;
if (remainingDepth > 0)
{
score = SimulateBranch(remainingDepth - 1, newState).Item2;
}
else
{
score = SimulateLeaf(newState);
}
if (score >= bestScore)
{
bestScore = score;
bestAction = new RequestedActions
{
DropBomb = true
};
}
}
return(bestAction, bestScore);
}
