//The procedure movePuzzle gets a valid random direction that the blank square of the
//puzzle can move in. Once a direction is found the blank square is updated and the
//square that is in the place where the blank square was moved to moves to the original
//location of the blank square simulataneously. So x goes to where y was and y goes to
//where x was. This is counted as a single move.
static private void movePuzzle()
{
Random ran = new Random();
//while loop calls the isValidMove static function of this class till a true a value
//is return from the function to ensure a valid direction is chosen.
int direction = ran.Next(4);
while (!isValidMove(direction))
{
direction = ran.Next(4);
}
if (direction == 0) //Move Left
{
PuzzleData.moveLeft(PuzzleData.xPuzzle, PuzzleData.yPuzzle);
}
else if (direction == 1) //Move Up
{
PuzzleData.moveUp(PuzzleData.xPuzzle, PuzzleData.yPuzzle);
}
else if (direction == 2) //Move Right
{
PuzzleData.moveRight(PuzzleData.xPuzzle, PuzzleData.yPuzzle);
}
else if (direction == 3) //Move Down
{
PuzzleData.moveDown(PuzzleData.xPuzzle, PuzzleData.yPuzzle);
}
}
//Method that updates the puzzle with the direction popped of the DFS stack. Then adds the new puzzle state
//to the visited list.
static private void movePuzzle()
{
int direction = (int)stackDFS.Pop();
if (direction == 0) //Move Left
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
}
else if (direction == 1) //Move Up
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
}
else if (direction == 2) //Move Right
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
}
else if (direction == 3) //Move Down
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
}
//if the trackBack flag is set as there were no moves, it doesn't add the move to the movesList stack.
if (!trackBack)
{
addMove(direction);
}
addVisitedList();
trackBack = false;
}
//Method that updates the puzzle with the direction popped of the DFS stack. Then adds the new puzzle state
//to the visited list.
static private void movePuzzle()
{
if (stackProgDFS.Count == 0)
{
xVisitedList.Clear();
yVisitedList.Clear();
depth++;
return;
}
int direction = (int)stackProgDFS.Pop();
//while (!isValidMove(direction))
//{
// if (stackProgDFS.Count > 0) { direction = (int)stackProgDFS.Pop(); } else { return; }
//}
if (direction == 0) //Move Left
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
}
else if (direction == 1) //Move Up
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
}
else if (direction == 2) //Move Right
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
}
else if (direction == 3) //Move Down
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
}
//only add move to move stack if track back hasn't been set
if (!trackBack)
{
addMove(direction);
}
addVisitedList();
trackBack = false;
}
//The method below checks for a valid move and then checks if the state has been visited
//if not the it adds that direction to the stackProgDFS variable.
static private void addNextMove()
{
bool moveAdded = false;
if (depthCounter >= depth)
{
previousState(moveAdded); return;
}
if ((isValidMove(0)) && (!moveAdded))
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
stackProgDFS.Push(0);
moveAdded = true;
}
}
if ((isValidMove(1)) && (!moveAdded))
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
stackProgDFS.Push(1);
moveAdded = true;
}
}
if ((isValidMove(2)) && (!moveAdded))
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
stackProgDFS.Push(2);
moveAdded = true;
}
}
if ((isValidMove(3)) && (!moveAdded))
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
stackProgDFS.Push(3);
moveAdded = true;
}
}
if (!moveAdded)
{
previousState(moveAdded);
}
else
{
depthCounter++;
}
}
//Addes a move into the openStates list. Different from the other two algorithms, instead of adding a
//direction it creates a new state instance which reflects the possible moves and add that to the openStates
//list.
static private void addNextMove()
{
ArrayList possibleMoves = new ArrayList(4);
for (int i = 0; i < 4; i++)
{
possibleMoves.Add(-1);
}
bool moveAdded = false;
if (isValidMove(0))
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
}
else
{
State st = new State(getManhattanDistance(0), xTempPuzzle, yTempPuzzle, 0);
openStates.Add(st);
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
moveAdded = true;
}
}
if (isValidMove(1))
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
}
else
{
State st = new State(getManhattanDistance(1), xTempPuzzle, yTempPuzzle, 1);
openStates.Add(st);
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
moveAdded = true;
}
}
if (isValidMove(2))
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
}
else
{
State st = new State(getManhattanDistance(2), xTempPuzzle, yTempPuzzle, 2);
openStates.Add(st);
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
moveAdded = true;
}
}
if (isValidMove(3))
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
}
else
{
State st = new State(getManhattanDistance(3), xTempPuzzle, yTempPuzzle, 3);
openStates.Add(st);
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
moveAdded = true;
}
}
//if there is no move possible then the algorithm backtracks.
if (!moveAdded)
{
int lastMove = (int)State.directions.Pop();
if (lastMove == 0)
{
lastMove = 2;
}
else if (lastMove == 1)
{
lastMove = 3;
}
else if (lastMove == 2)
{
lastMove = 0;
}
else if (lastMove == 3)
{
lastMove = 1;
}
State.directions.Push(lastMove);
trackBack = true;
}
}
//The method below checks for a valid move and then checks if the state has been visited
//if not the it adds that direction to the stackDFS variable.
static private void addNextMove()
{
bool moveAdded = false;
if (isValidMove(0))
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
stackDFS.Push(0);
moveAdded = true;
}
}
if (isValidMove(1))
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
stackDFS.Push(1);
moveAdded = true;
}
}
if (isValidMove(2))
{
PuzzleData.moveRight(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveLeft(xTempPuzzle, yTempPuzzle);
stackDFS.Push(2);
moveAdded = true;
}
}
if (isValidMove(3))
{
PuzzleData.moveDown(xTempPuzzle, yTempPuzzle);
if (isVisitedState())
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
}
else
{
PuzzleData.moveUp(xTempPuzzle, yTempPuzzle);
stackDFS.Push(3);
moveAdded = true;
}
}
//if no move could be found happens when the current state cannot get out because all the
//neighbouring states have already been expanded. It adds the opposite of the last move made
//which makes the puzzle go back one step.
if (!moveAdded)
{
int lastMove = (int)stackMoves.Pop();
if (lastMove == 0)
{
lastMove = 2;
}
else if (lastMove == 1)
{
lastMove = 3;
}
else if (lastMove == 2)
{
lastMove = 0;
}
else if (lastMove == 3)
{
lastMove = 1;
}
stackDFS.Push(lastMove);
trackBack = true; //trackBack flag is set for the movePuzzle method. see there for more explanation.
}
}