def move_to_top(current_node, visited_map, queue):
"""function moves the empty state up one position"""
#The function checks to see if the move is valid (if it is on the board),
#if the move left is valide, it will create a temporary new_state and it will
#call the function to swap the empty position with the left position. The new_state is
#returned and if that state has not been previously visited, the counter is incremented
#for nodes created and the node is put into the queue. This process is the same for each
#possible position: right, down, and left. The only change is math that is done to look
#at each position.
if (current_node.empty_spot - 3) < 0:
return
new_empty_spot = current_node.empty_spot - 3
new_state = current_node.start_state[:]
new_state = swap_empty_position(new_state, current_node.empty_spot,
new_empty_spot)
if not check_visited(visited_map, new_state):
set_glob_counter()
add_to_visited(visited_map, new_state, COUNTER)
new_node = Node(new_state)
new_node.empty_spot = new_node.find_empty_position()
new_node.depth = new_node.set_depth(current_node)
new_node.set_path = new_node.set_path(current_node, new_empty_spot)
queue.append(new_node)
def move_to_left(current_node, visited_map, queue):
"""function moves the empty state left one position if possible."""
if (current_node.empty_spot % 3) == 0:
return
new_empty_spot = current_node.empty_spot - 1
new_state = current_node.start_state[:]
new_state = swap_empty_position(new_state, current_node.empty_spot,
new_empty_spot)
if not check_visited(visited_map, new_state):
set_glob_counter()
add_to_visited(visited_map, new_state, COUNTER)
new_node = Node(new_state)
new_node.empty_spot = new_node.find_empty_position()
new_node.depth = new_node.set_depth(current_node)
new_node.set_path = new_node.set_path(current_node, new_empty_spot)
queue.append(new_node)
def move_to_bottom(current_node, visited_map, queue):
"""function moves the empty state down one position"""
if (current_node.empty_spot + 3) > 8:
return
new_empty_spot = current_node.empty_spot + 3
new_state = current_node.start_state[:]
new_state = swap_empty_position(new_state, current_node.empty_spot,
new_empty_spot)
if not check_visited(visited_map, new_state):
set_glob_counter()
add_to_visited(visited_map, new_state, COUNTER)
new_node = Node(new_state)
new_node.empty_spot = new_node.find_empty_position()
new_node.depth = new_node.set_depth(current_node)
new_node.set_path = new_node.set_path(current_node, new_empty_spot)
queue.append(new_node)
def move_to_left(current_node, visited_map, queue):
"""function moves the empty state left one position if possible."""
if (current_node.empty_spot % 3) == 0:
return
# from this point, the same steps are repeated as the move_to_up function, but now swapping left
new_empty_spot = current_node.empty_spot - 1
new_state = current_node.start_state[:]
new_state = swap_empty_position(new_state, current_node.empty_spot, new_empty_spot)
if not check_visited(visited_map, new_state):
set_glob_counter()
add_to_visited(visited_map, new_state, COUNTER)
new_node = Node(new_state)
new_node.empty_spot = new_node.find_empty_position()
new_node.set_path = new_node.set_path(current_node, new_empty_spot)
new_node.depth = new_node.set_depth(current_node)
new_node.heuristic = new_node.calculate_misplaced_tiles()
Q.heappush(queue, (new_node.heuristic, COUNTER, new_node))
def move_to_bottom(current_node, visited_map, queue):
"""function moves the empty state down one position"""
if (current_node.empty_spot + 3) > 8:
return
new_empty_spot = current_node.empty_spot + 3
new_state = current_node.start_state[:]
new_state = swap_empty_position(new_state, current_node.empty_spot,
new_empty_spot)
# from this point, the same steps are repeated as the move_to_up function, but now swapping down
if not check_visited(visited_map, new_state):
set_glob_counter()
add_to_visited(visited_map, new_state, COUNTER)
new_node = Node(new_state)
new_node.empty_spot = new_node.find_empty_position()
new_node.set_path = new_node.set_path(current_node, new_empty_spot)
new_node.depth = new_node.set_depth(current_node)
new_node.heuristic = new_node.calculate_manhattan_distance()
Q.heappush(queue, (new_node.heuristic, COUNTER, new_node))
def move_to_right(current_node, visited_map, stack):
"""function moves the empty state right one position"""
if ((current_node.empty_spot + 1) % 3) == 0:
return
new_empty_spot = current_node.empty_spot + 1
new_state = current_node.start_state[:]
new_state = swap_empty_position(new_state, current_node.empty_spot,
new_empty_spot)
if not check_visited(visited_map, new_state):
set_glob_counter()
add_to_visited(visited_map, new_state, COUNTER)
new_node = Node(new_state)
new_node.empty_spot = new_node.find_empty_position()
new_node.depth = new_node.set_depth(current_node)
if new_node.depth > MAX_DEPTH:
increment_max_depth(new_node.depth)
stack.append(new_node)
def move_to_top(current_node, visited_map, queue):
"""function moves the empty state up one position"""
if (current_node.empty_spot - 3) < 0:
return
new_empty_spot = current_node.empty_spot - 3
#copies the current state to a temporary variable called new_state
new_state = current_node.start_state[:]
#makes the swap for the empty position and tile above the empty spot
new_state = swap_empty_position(new_state, current_node.empty_spot, new_empty_spot)
#if the new_state is not in the visited map then proceed with making a new node and adding it to the queue
if not check_visited(visited_map, new_state):
set_glob_counter()
add_to_visited(visited_map, new_state, COUNTER)
new_node = Node(new_state)
new_node.empty_spot = new_node.find_empty_position()
new_node.set_path = new_node.set_path(current_node, new_empty_spot)
new_node.depth = new_node.set_depth(current_node)
new_node.heuristic = new_node.calculate_misplaced_tiles()
Q.heappush(queue, (new_node.heuristic, COUNTER, new_node))