def dfs(board, start, goal):
stack = [start]
visited = set()
full_path = []
while stack:
current = stack.pop()
full_path.append(current)
if current == goal:
return full_path
for direction in ["up", "right", "down", "left"]: # Other orders are fine too.
row_offset, col_offset = config.offsets[direction]
neighbour = (current[0] + row_offset, current[1] + col_offset)
if helpers.is_legal_pos(board, neighbour) and neighbour not in visited:
stack.append(neighbour)
visited.add(neighbour)
def bfs(board, start, goal):
queue = deque()
queue.append(start)
visited = set()
full_path = []
while queue:
current = queue.popleft()
full_path.append(current)
if current == goal:
return full_path
for direction in ["up", "right", "down", "left"]:
row_offset, col_offset = config.offsets[direction]
neighbour = (current[0] + row_offset, current[1] + col_offset)
if helpers.is_legal_pos(board, neighbour) and neighbour not in visited:
queue.append(neighbour)
visited.add(neighbour)
def a_star(board, start_pos, goal_pos):
pq = PriorityQueue()
pq.put(start_pos, 0)
g_values = {}
g_values[start_pos] = 0
full_path = []
while not pq.is_empty():
current_cell_pos = pq.get()
full_path.append(current_cell_pos)
if current_cell_pos == goal_pos:
return full_path
for direction in ["up", "right", "down", "left"]:
row_offset, col_offset = config.offsets[direction]
neighbour = (current_cell_pos[0] + row_offset, current_cell_pos[1] + col_offset)
new_cost = g_values[current_cell_pos] + 1 # Would be edge weight in a weighted graph
if helpers.is_legal_pos(board, neighbour):
# Second check only applies to weighted graph.
if neighbour not in g_values or new_cost < g_values[neighbour]:
g_values[neighbour] = new_cost
f_value = new_cost + heuristic(goal_pos, neighbour)
pq.put(neighbour, f_value)