//this method return the end location and also return/populates the backtrack array with the counter/step value which will be used later to get the shortest distance
private MazeCell MoveRobotInBFSManner(int row, int col, int rowlength, int collength, char[,] maze, int[,] backtrack, char endgoal)
{
//We create the mazecell
int counter = 0;
MazeCell startnode = new MazeCell(row, col, counter);
Queue <MazeCell> myqueue = new Queue <MazeCell>();
MazeCell parent = null;
int rowno = 0;
int colno = 0;
//Look if the given maze is not allowed to edit..then we can use a dictionary of Mazecell and query the mazecell collection to see whether these row and col is visited
//This can be used if the given maze is not allowed to edit...and we can use visited as the bool in the dictionary
Dictionary <string, bool> MazeCellVisitTracker = new Dictionary <string, bool>();
//Mark the start as visited
MazeCellVisitTracker.Add(startnode.Row + "-" + startnode.Col, true);
myqueue.Enqueue(startnode);
while (myqueue.Count != 0)
{
parent = myqueue.Dequeue();
counter = parent.StepNumber;
//The robot can move in four direction North, south, east and west
//north
rowno = parent.Row - 1;
colno = parent.Col;
MazeCell possiblemove = RobotMove(rowno, colno, rowlength, collength, counter, maze, endgoal, MazeCellVisitTracker);
if (possiblemove != null)
{
//this mean robot has a possible solution or found the goal
if (possiblemove.LastCell)
{
return(possiblemove);
}
else
{
//this will be a possible sln move so add it to queue and backtrack
myqueue.Enqueue(possiblemove); //this already contains the counter incremented
backtrack[possiblemove.Row, possiblemove.Col] = possiblemove.StepNumber;
}
}
//south
rowno = parent.Row + 1;
colno = parent.Col;
possiblemove = RobotMove(rowno, colno, rowlength, collength, counter, maze, endgoal, MazeCellVisitTracker);
if (possiblemove != null)
{
//this mean robot has a possible solution or found the goal
if (possiblemove.LastCell)
{
return(possiblemove);
}
else
{
//this will be a possible sln move so add it to queue and backtrack
myqueue.Enqueue(possiblemove); //this already contains the counter incremented
backtrack[possiblemove.Row, possiblemove.Col] = possiblemove.StepNumber;
}
}
//east
rowno = parent.Row;
colno = parent.Col + 1;
possiblemove = RobotMove(rowno, colno, rowlength, collength, counter, maze, endgoal, MazeCellVisitTracker);
if (possiblemove != null)
{
//this mean robot has a possible solution or found the goal
if (possiblemove.LastCell)
{
return(possiblemove);
}
else
{
//this will be a possible sln move so add it to queue and backtrack
myqueue.Enqueue(possiblemove); //this already contains the counter incremented
backtrack[possiblemove.Row, possiblemove.Col] = possiblemove.StepNumber;
}
}
//west
rowno = parent.Row;
colno = parent.Col - 1;
possiblemove = RobotMove(rowno, colno, rowlength, collength, counter, maze, endgoal, MazeCellVisitTracker);
if (possiblemove != null)
{
//this mean robot has a possible solution or found the goal
if (possiblemove.LastCell)
{
return(possiblemove);
}
else
{
//this will be a possible sln move so add it to queue and backtrack
myqueue.Enqueue(possiblemove); //this already contains the counter incremented
backtrack[possiblemove.Row, possiblemove.Col] = possiblemove.StepNumber;
}
}
}
return(null);
}
