private static void explore(int delay)
{
GemPuzzleForm oGemPuzzleForm = GemPuzzleForm.getInstance();
PuzzleState currentState;
int[] tmpValues = new int[Constants.InvisibleValue];
oGemPuzzleForm.Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
for (int i = Constants.MinimumValue; i < Constants.InvisibleValue; i++)
{
tmpValues[i] = oGemPuzzleForm.gemButtons[i].Value;
}
}));
currentState = new PuzzleState(tmpValues);
while (Solver.Position < (Solver.SolutionMoves.Length - 1))
{
currentState = new PuzzleState(currentState, Solver.SolutionMoves[++Solver.Position]);
Solver.updateTiles(currentState);
Thread.Sleep(delay);
}
oGemPuzzleForm.Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
oGemPuzzleForm.ControlButtons = true;
}));
}
/// <summary>
/// Given a state, it calculates a new state randomly.
/// </summary>
/// <param name="state">The state containing the next possible and valid moves.</param>
/// <returns>A state created randomly from a given state.</returns>
public static PuzzleState SetNextStateRandomly(PuzzleState state)
{
PuzzleState tmpState;
Random nextMove = new Random(DateTime.Now.Millisecond);
int index = nextMove.Next(0, state.ValidMoves.Length);
tmpState = new PuzzleState(state.Values, state.ValidMoves[index]);
return(tmpState);
}
private static void updateTiles(PuzzleState state)
{
GemPuzzleForm.getInstance().Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
for (int j = Constants.MinimumValue; j < Constants.InvisibleValue; j++)
{
GemPuzzleForm.getInstance().gemButtons[j].Value = state.Values[j];
}
}));
}
private static void shuffleTiles()
{
GemPuzzleForm oGemPuzzleForm = GemPuzzleForm.getInstance();
Solver.StartNode = Solver.getCurrentState();
for (int i = 0; i < 50; i++)
{
Solver.StartNode = PuzzleState.SetNextStateRandomly(Solver.StartNode);
Solver.updateTiles(Solver.StartNode);
Thread.Sleep(100);
}
}
/// <summary>
/// This constructor is used when it is only necessary to create a copy ot the current state in the puzzle.
/// </summary>
public PuzzleState(PuzzleState state)
{
this.NonVisiblePosition = state.NonVisiblePosition;
this.Values = new int[state.Values.Length];
state.Values.CopyTo(this.Values, 0);
this.LastMove = state.LastMove;
this.Heuristic1 = state.Heuristic1;
this.Heuristic2 = state.Heuristic2;
this.Cost = state.Cost;
this.PreviousMoves = new List<byte>(state.PreviousMoves);
this.ValidMoves = new byte[state.ValidMoves.Length];
state.ValidMoves.CopyTo(this.ValidMoves, 0);
}
/// <summary>
/// This constructor is used when it is only necessary to create a copy ot the current state in the puzzle.
/// </summary>
public PuzzleState(PuzzleState state)
{
this.NonVisiblePosition = state.NonVisiblePosition;
this.Values = new int[state.Values.Length];
state.Values.CopyTo(this.Values, 0);
this.LastMove = state.LastMove;
this.Heuristic1 = state.Heuristic1;
this.Heuristic2 = state.Heuristic2;
this.Cost = state.Cost;
this.PreviousMoves = new List <byte>(state.PreviousMoves);
this.ValidMoves = new byte[state.ValidMoves.Length];
state.ValidMoves.CopyTo(this.ValidMoves, 0);
}
private static int searchInList(List <PuzzleState> list, PuzzleState state)
{
int index = -1;
for (int i = 0; (i < list.Count) && (index == -1); i++)
{
if (list[i].IsEqualTo(state))
{
index = i;
}
}
return(index);
}
/// <summary>
/// This constructor creates a new state, and updates cost, heuristic, none visible position, etc.
/// </summary>
/// <param name="state">This is the parent node</param>
/// <param name="nextMovePosition">This is the position in the array that actually creates the new state.</param>
public PuzzleState(PuzzleState state, byte nextMovePosition)
{
this.Values = new int[Constants.InvisibleValue];
state.Values.CopyTo(this.Values, 0);
this.LastMove = state.NonVisiblePosition;
this.NonVisiblePosition = nextMovePosition;
this.Values[this.LastMove] = this.Values[nextMovePosition];
this.Values[nextMovePosition] = Constants.InvisibleValue;
this.Heuristic1 = getHeuristic1();
this.Heuristic2 = getHeuristic2();
this.Cost = state.Cost + 1;
this.PreviousMoves = new List<byte>(state.PreviousMoves);
this.PreviousMoves.Add(nextMovePosition);
this.setValidMovements();
}
/// <summary>
/// This constructor creates a new state, and updates cost, heuristic, none visible position, etc.
/// </summary>
/// <param name="state">This is the parent node</param>
/// <param name="nextMovePosition">This is the position in the array that actually creates the new state.</param>
public PuzzleState(PuzzleState state, byte nextMovePosition)
{
this.Values = new int[Constants.InvisibleValue];
state.Values.CopyTo(this.Values, 0);
this.LastMove = state.NonVisiblePosition;
this.NonVisiblePosition = nextMovePosition;
this.Values[this.LastMove] = this.Values[nextMovePosition];
this.Values[nextMovePosition] = Constants.InvisibleValue;
this.Heuristic1 = getHeuristic1();
this.Heuristic2 = getHeuristic2();
this.Cost = state.Cost + 1;
this.PreviousMoves = new List <byte>(state.PreviousMoves);
this.PreviousMoves.Add(nextMovePosition);
this.setValidMovements();
}
/// <summary>
/// Checks if two states have the same value arrangement (the tiles).
/// </summary>
/// <param name="state"></param>
/// <returns></returns>
public bool IsEqualTo(PuzzleState state)
{
bool equals = false;
if ((state.Heuristic2 == this.Heuristic2) && (state.Heuristic1 == this.Heuristic1))
{
equals = true;
for (int i = Constants.MinimumValue; (i < Constants.InvisibleValue) && equals; i++)
{
if (state.Values[i] != this.Values[i])
{
equals = false;
}
}
}
return(equals);
}
private static PuzzleState getCurrentState()
{
GemPuzzleForm oGemPuzzleForm;
PuzzleState state;
int[] currentArray = new int[Constants.InvisibleValue];
oGemPuzzleForm = GemPuzzleForm.getInstance();
oGemPuzzleForm.Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
for (int i = Constants.MinimumValue; i < Constants.InvisibleValue; i++)
{
currentArray[i] = oGemPuzzleForm.gemButtons[i].Value;
}
}));
state = new PuzzleState(currentArray);
return(state);
}
private static PuzzleState getBestNodeFromOpenList()
{
PuzzleState bestState;
int index = 0;
if (Solver.OpenList.Count > 1)
{
for (int i = 1; i < Solver.OpenList.Count; i++)
{
if ((Solver.OpenList[i].GetFofN()) < Solver.OpenList[index].GetFofN())
{
index = i;
}
}
}
bestState = new PuzzleState(Solver.OpenList[index]);
Solver.OpenList.RemoveAt(index);
return(bestState);
}
private static void updateTiles(PuzzleState state)
{
GemPuzzleForm.getInstance().Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
for (int j = Constants.MinimumValue; j < Constants.InvisibleValue; j++)
{
GemPuzzleForm.getInstance().gemButtons[j].Value = state.Values[j];
}
}));
}
private static void shuffleTiles()
{
GemPuzzleForm oGemPuzzleForm = GemPuzzleForm.getInstance();
Solver.StartNode = Solver.getCurrentState();
for (int i = 0; i < 50; i++)
{
Solver.StartNode = PuzzleState.SetNextStateRandomly(Solver.StartNode);
Solver.updateTiles(Solver.StartNode);
Thread.Sleep(100);
}
}
private static int searchInList(List<PuzzleState> list, PuzzleState state)
{
int index = -1;
for (int i = 0; (i < list.Count) && (index == -1); i++)
{
if (list[i].IsEqualTo(state))
{
index = i;
}
}
return index;
}
private static void main()
{
while (true)
{
switch (Solver.Action)
{
case Actions.Shuffling:
Solver.shuffleTiles();
Solver.Action = Actions.None;
break;
case Actions.Solving:
Solver.findSolution();
Solver.Action = Actions.Solved;
break;
case Actions.Solved:
GemPuzzleForm.getInstance().Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
GemPuzzleForm.getInstance().Moves.Text = "Total Moves: " + (Solver.GoalNode.PreviousMoves.Count - 1).ToString();
}));
Solver.SolutionMoves = new byte[Solver.GoalNode.PreviousMoves.Count];
Solver.GoalNode.PreviousMoves.CopyTo(Solver.SolutionMoves);
Solver.Position = 0;
Solver.Action = Actions.Explore;
break;
case Actions.GoToStart:
PuzzleState state;
if (Solver.Position > 0)
{
state = Solver.getCurrentState();
while (Solver.Position > 0)
{
state = new PuzzleState(state, Solver.SolutionMoves[--Solver.Position]);
Solver.updateTiles(state);
Thread.Sleep(100);
}
}
Solver.Action = Actions.Waiting;
break;
case Actions.GoBackward:
if (Solver.Position > 0)
{
state = Solver.getCurrentState();
state = new PuzzleState(state, Solver.SolutionMoves[--Solver.Position]);
Solver.updateTiles(state);
}
Solver.Action = Actions.Waiting;
break;
case Actions.Explore:
Solver.explore(500);
Solver.Action = Actions.Waiting;
break;
case Actions.GoForward:
if (Solver.Position < (Solver.SolutionMoves.Length - 1))
{
state = Solver.getCurrentState();
state = new PuzzleState(state, Solver.SolutionMoves[++Solver.Position]);
Solver.updateTiles(state);
}
Solver.Action = Actions.Waiting;
break;
case Actions.GoToEnd:
Solver.explore(100);
Solver.Action = Actions.Waiting;
break;
default:
// Do nothing.
break;
}
}
}
private static PuzzleState getCurrentState()
{
GemPuzzleForm oGemPuzzleForm;
PuzzleState state;
int[] currentArray = new int[Constants.InvisibleValue];
oGemPuzzleForm = GemPuzzleForm.getInstance();
oGemPuzzleForm.Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
for (int i = Constants.MinimumValue; i < Constants.InvisibleValue; i++)
{
currentArray[i] = oGemPuzzleForm.gemButtons[i].Value;
}
}));
state = new PuzzleState(currentArray);
return state;
}
private static PuzzleState getBestNodeFromOpenList()
{
PuzzleState bestState;
int index = 0;
if (Solver.OpenList.Count > 1)
{
for (int i = 1; i < Solver.OpenList.Count; i++)
{
if ((Solver.OpenList[i].GetFofN()) < Solver.OpenList[index].GetFofN())
{
index = i;
}
}
}
bestState = new PuzzleState(Solver.OpenList[index]);
Solver.OpenList.RemoveAt(index);
return bestState;
}
/// <summary>
/// Algorithm A*
/// f(n) = h(n) + g(n).
/// Where:
/// n: is the current state.
/// f: is the function that decides which state is going to be explored.
/// h: is the heuristic (the distance from the current state to the goal state.
/// g: is the cost to get from the start state to the current state n.
/// </summary>
private static void findSolution()
{
List<PuzzleState> successorNodes;
int index;
bool notIgnore;
int nodesVisited = 0;
// 1. Create a node containing the goal state (Solver.GoalNode).
// 2. Create a node containing the start state (Solver.StartNode)
Solver.StartNode = Solver.getCurrentState();
// 3. Put the start node on the OpenList.
Solver.OpenList.Add(Solver.StartNode);
// 4. While OpenList is not empty.
while (Solver.OpenList.Count > 0)
{
// 5. Get the node off the open list with the lowest f and call it current node (Solver.CurrentNode).
Solver.CurrentNode = Solver.getBestNodeFromOpenList();
// 6. If Solver.CurrentNode is the same state as Solver.GoalState we have found the solution; break from the while loop
if (Solver.GoalNode.IsEqualTo(Solver.CurrentNode))
{
Solver.GoalNode = new PuzzleState(Solver.CurrentNode);
Solver.CurrentNode = null;
nodesVisited = Solver.ClosedList.Count + 1;
Solver.OpenList.Clear();
Solver.ClosedList.Clear();
}
else
{
// 7. Generate each state that can come after CurrentNode.
successorNodes = new List<PuzzleState>(Solver.CurrentNode.ValidMoves.Length);
for (int i = 0; i < Solver.CurrentNode.ValidMoves.Length; i++)
{
successorNodes.Add(new PuzzleState(Solver.CurrentNode, Solver.CurrentNode.ValidMoves[i]));
}
foreach (PuzzleState state in successorNodes)
{ // 8. For each successor node of current node:
// 9. If successor node is on the Open List but the existing one is a good or better, then disscard this successor and continue.
notIgnore = true;
index = Solver.searchInList(Solver.OpenList, state);
if (index > -1)
{
if (state.GetFofN() < Solver.OpenList[index].GetFofN())
{
// 9.1 Remove occurrances of successor node from Open List.
Solver.OpenList.RemoveAt(index);
}
else
{
notIgnore = false;
}
}
// 10. If successor node is on the Closed List but the existing one is a good or better, then disscard this successor and continue.
index = Solver.searchInList(Solver.ClosedList, state);
if (index > -1)
{
if (state.GetFofN() < Solver.ClosedList[index].GetFofN())
{
// 10.1 Remove occurrances of successor node from Closed List.
Solver.ClosedList.RemoveAt(index);
}
else
{
notIgnore = false;
}
}
// 11. Add successor node to the Open List.
if (notIgnore)
{
Solver.OpenList.Add(state);
}
}
// 14. Add CurrentNode to the Closed List.
Solver.ClosedList.Add(new PuzzleState(Solver.CurrentNode));
nodesVisited = Solver.ClosedList.Count;
}
GemPuzzleForm.getInstance().Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
GemPuzzleForm.getInstance().Nodes.Text = "Nodes Visited: " + nodesVisited.ToString();
}));
}
}
private static void explore(int delay)
{
GemPuzzleForm oGemPuzzleForm = GemPuzzleForm.getInstance();
PuzzleState currentState;
int[] tmpValues = new int[Constants.InvisibleValue];
oGemPuzzleForm.Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
for (int i = Constants.MinimumValue; i < Constants.InvisibleValue; i++)
{
tmpValues[i] = oGemPuzzleForm.gemButtons[i].Value;
}
}));
currentState = new PuzzleState(tmpValues);
while (Solver.Position < (Solver.SolutionMoves.Length - 1))
{
currentState = new PuzzleState(currentState, Solver.SolutionMoves[++Solver.Position]);
Solver.updateTiles(currentState);
Thread.Sleep(delay);
}
oGemPuzzleForm.Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
oGemPuzzleForm.ControlButtons = true;
}));
}
private static void main()
{
while (true)
{
switch (Solver.Action)
{
case Actions.Shuffling:
Solver.shuffleTiles();
Solver.Action = Actions.None;
break;
case Actions.Solving:
Solver.findSolution();
Solver.Action = Actions.Solved;
break;
case Actions.Solved:
GemPuzzleForm.getInstance().Invoke(new System.Windows.Forms.MethodInvoker(() =>
{
GemPuzzleForm.getInstance().Moves.Text = "Total Moves: " + (Solver.GoalNode.PreviousMoves.Count - 1).ToString();
}));
Solver.SolutionMoves = new byte[Solver.GoalNode.PreviousMoves.Count];
Solver.GoalNode.PreviousMoves.CopyTo(Solver.SolutionMoves);
Solver.Position = 0;
Solver.Action = Actions.Explore;
break;
case Actions.GoToStart:
PuzzleState state;
if (Solver.Position > 0)
{
state = Solver.getCurrentState();
while (Solver.Position > 0)
{
state = new PuzzleState(state, Solver.SolutionMoves[--Solver.Position]);
Solver.updateTiles(state);
Thread.Sleep(100);
}
}
Solver.Action = Actions.Waiting;
break;
case Actions.GoBackward:
if (Solver.Position > 0)
{
state = Solver.getCurrentState();
state = new PuzzleState(state, Solver.SolutionMoves[--Solver.Position]);
Solver.updateTiles(state);
}
Solver.Action = Actions.Waiting;
break;
case Actions.Explore:
Solver.explore(500);
Solver.Action = Actions.Waiting;
break;
case Actions.GoForward:
if (Solver.Position < (Solver.SolutionMoves.Length - 1))
{
state = Solver.getCurrentState();
state = new PuzzleState(state, Solver.SolutionMoves[++Solver.Position]);
Solver.updateTiles(state);
}
Solver.Action = Actions.Waiting;
break;
case Actions.GoToEnd:
Solver.explore(100);
Solver.Action = Actions.Waiting;
break;
default:
// Do nothing.
break;
}
}
}
/// <summary>
/// Given a state, it calculates a new state randomly.
/// </summary>
/// <param name="state">The state containing the next possible and valid moves.</param>
/// <returns>A state created randomly from a given state.</returns>
public static PuzzleState SetNextStateRandomly(PuzzleState state)
{
PuzzleState tmpState;
Random nextMove = new Random(DateTime.Now.Millisecond);
int index = nextMove.Next(0, state.ValidMoves.Length);
tmpState = new PuzzleState(state.Values, state.ValidMoves[index]);
return tmpState;
}
/// <summary>
/// Checks if two states have the same value arrangement (the tiles).
/// </summary>
/// <param name="state"></param>
/// <returns></returns>
public bool IsEqualTo(PuzzleState state)
{
bool equals = false;
if ((state.Heuristic2 == this.Heuristic2) && (state.Heuristic1 == this.Heuristic1))
{
equals = true;
for (int i = Constants.MinimumValue; (i < Constants.InvisibleValue) && equals; i++)
{
if (state.Values[i] != this.Values[i])
{
equals = false;
}
}
}
return equals;
}
