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Flooding the maze solution in Clear category for Open Labyrinth by kumaus
"""
This algorithm actually finds the shortest route in the maze.
It could be visualized as colour spreading through the maze
It works by following all potential routes at the same time, in the list "routes".
These routes are successively expanded, step by step.
If a route reaches a free point in the map, this is "blocked" by giving it the value 2.
any route intersecting this point at a later time will be too slow
and can therefore be ignored.
If a route can not be expanded to a free point, it terminates (dead end)
The first route to reach the goal is the winner.
"""
def checkio(maze_map):
start = (1,1)
goal = (10, 10)
routes = [(start, "")]
maze_map[start[0]][start[1]] = 2
while routes:
pos, path = routes.pop(0)
if pos == goal:
return path
if not maze_map[pos[0]+1][pos[1]]:
maze_map[pos[0]+1][pos[1]] = 2
routes.append(((pos[0]+1, pos[1]), path + 'S'))
if not maze_map[pos[0]][pos[1]+1]:
maze_map[pos[0]][pos[1]+1] = 2
routes.append(((pos[0], pos[1]+1), path + 'E'))
if not maze_map[pos[0]-1][pos[1]]:
maze_map[pos[0]-1][pos[1]] = 2
routes.append(((pos[0]-1, pos[1]), path + 'N'))
if not maze_map[pos[0]][pos[1]-1]:
maze_map[pos[0]][pos[1]-1] = 2
routes.append(((pos[0], pos[1]-1), path + 'W'))
return "no path"
def run():
#This code using only for self-checking and not necessary for auto-testing
def check_route(func, labyrinth):
MOVE = {"S": (1, 0), "N": (-1, 0), "W": (0, -1), "E": (0, 1)}
#copy maze
route = func([row[:] for row in labyrinth])
pos = (1, 1)
goal = (10, 10)
for i, d in enumerate(route):
move = MOVE.get(d, None)
if not move:
print("Wrong symbol in route")
return False
pos = pos[0] + move[0], pos[1] + move[1]
if pos == goal:
return True
if labyrinth[pos[0]][pos[1]] == 1:
print("Player in the pit")
return False
print("Player did not reach exit")
return False
# These assert are using only for self-testing as examples.
assert check_route(checkio, [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1],
[1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1],
[1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]), "First maze"
assert check_route(checkio, [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]), "Empty maze"
assert check_route(checkio, [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]), "Up and down maze"
assert check_route(checkio, [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]), "Dotted maze"
assert check_route(checkio, [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1],
[1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1],
[1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1],
[1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]), "Need left maze"
assert check_route(checkio, [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1],
[1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1],
[1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1],
[1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]), "The big dead end."
print("The local tests are done.")
Sept. 15, 2015