def scan_grid(grid, start=(0, 0)):
"""Scan all grid, so we can find a path from 'start' to any point"""
q = deque()
q.append(start)
came_from = {start: None}
while len(q) > 0:
current_pos = q.popleft()
neighbors = gh.get_neighbors(grid, current_pos[0], current_pos[1])
for neighbor in neighbors:
if neighbor not in came_from:
q.append(neighbor)
came_from[neighbor] = current_pos
return came_from
def find_path_greedy(grid, start, end):
pq = PriorityQueue()
pq.put((0, start))
came_from = {start: None}
while not pq.empty():
current_pos = pq.get()[1]
if current_pos == end:
break
neighbors = gh.get_neighbors(grid, current_pos[0], current_pos[1])
for neighbor in neighbors:
if neighbor not in came_from:
priority = gh.heuristic_distance(neighbor, end, type="m")
pq.put((priority, neighbor))
came_from[neighbor] = current_pos
return came_from
def find_path_a_star(grid, start, end):
pq = PriorityQueue()
pq.put((0, start))
came_from = {start: None}
costs = {start: 0}
while not pq.empty():
current_pos = pq.get()[1]
if current_pos == end:
break
neighbors = gh.get_neighbors(grid, current_pos[0], current_pos[1])
for neighbor in neighbors:
new_cost = costs[current_pos] + gh.get_cost(grid, neighbor)
if neighbor not in costs or new_cost < costs[neighbor]:
costs[neighbor] = new_cost
priority = new_cost + gh.heuristic_distance(neighbor, end)
pq.put((priority, neighbor))
came_from[neighbor] = current_pos
return came_from