# If you want the available input get in LIST_PUZZLE_DATA
python3 N-puzzle-DFS.py (numRow = 3) noRandom (numMoves) Recursive 
# If you want to generate random data
python3 N-puzzle-DFS.py (numRow) Random (numMoves) Recursive

DFS(state): 
# list_action: Storing list direction in recursion
# The purpose is to print the results

Mark the state is visited
If state is Goal State: 
    print result in list_action and break

Traverse the possible directions (dir) in LegalMoves(state):
    # Next state when going in the direction (dir)
    next_state = result(state, dir) 
    if next_state is not visited
        push dir in list_action
        DFS(next_state) # Recursive next_state
        pop dir in list_action # Backtracking

# If you want the available input get in LIST_PUZZLE_DATA
python3 N-puzzle-DFS.py (numRow = 3) noRandom (numMoves) noRecursive 
# If you want to generate random data
python3 N-puzzle-DFS.py (numRow) Random (numMoves) noRecursive

Since the recursive algorithm uses a lot of stack memory, python's stack memory is very small,    
so the algorithm using recursion fails due to memory overflow, because the depth of the DFS algorithm will
follows the factorial function of N * N. Hence, we will use recursive elimination to fix this.

python Sudoku.py

1. Fill-predetermined button: Using pencil marking strategy before solving.
2. Solve button: Solving the problem.
3. Reset button: Reset the GUI. Willing to solve another problem.
4. There are 4 mode in order to create initial state of Sudoku.
	a, Easy mode.
	b, Medium mode.
	c, Hard mode.
	d, Expert mode.

* By click the left mouse button, we can:
	1. Select start cell: orange color
	2. Select goal cell: blue color
	3. Draw to wall: black color
	4. Change the step cost (default: 1 to 5), click 1 button (has ! notation), and draw
	changed cell with step cost: 5: yellow color
	5. Back to default mode, click button 2 (has @ notation).
* By click the right mouse button, we can:
	1. Change the current cell to begin state: white color
* After we has start and goal, other configuration cell, please use space bar to find the path.
* The reset mode will be update in next version, we apologize for the inconvenience.