def bfs(start_tile, end_tile):
"""
Breadth-first search algorithm
:param start_tile: Tile object, start tile of board
:param end_tile: Tile object, end tile of board
:return:
"""
queue = Queue()
queue.put(start_tile)
came_from = {}
came_from[start_tile] = None
has_been_next_tile = []
while not queue.empty():
current_tile = queue.get()
current_tile.visit()
if current_tile == end_tile:
break
for next_tile in current_tile.neighbours:
if next_tile not in has_been_next_tile:
has_been_next_tile.append(next_tile)
if next_tile not in came_from:
queue.put(next_tile)
came_from[next_tile] = current_tile
current_tile.visit()
return came_from, has_been_next_tile
def bfs(start, end):
"""
Breadth first search. Takes a start tile and end tile, and uses
their neighbour list to traverse.
Uses the LIFO queue in queues.py.
:param start: Tile
:param end: Tile
:return: came_from, dictionary with all tiles, and where we came from (parent).
success, True or False. If the algorithm found the end tile or not.
has_been_next, list over tiles that has been considered as the next tile.
"""
frontier = Queue()
frontier.add(start)
came_from = {start: None}
success = False
has_been_next = []
while not frontier.empty():
current = frontier.pop()
current.visit()
if current == end:
print("Breadth First Search, successful.")
success = True
break
for next_tile in current.neighbours:
if next_tile not in has_been_next:
has_been_next.append(next_tile)
if next_tile not in came_from:
frontier.add(next_tile)
came_from[next_tile] = current
return came_from, success, has_been_next
class NumpadBase:
KEYS = '0123456789xy'
# this signals a need to stop user interaction and re-look at ux stack
ABORT_KEY = '\xff'
def __init__(self):
# once pressed, and released; keys show up in this queue
self._changes = Queue(24)
self.key_pressed = ''
self.debug = 0 # 0..2
self.last_event_time = utime.ticks_ms()
async def get(self):
# Get keypad events. Single-character strings.
return await self._changes.get()
def get_nowait(self):
# Poll if anything ready: not async!
return self._changes.get_nowait()
def empty(self):
return self._changes.empty()
def abort_ux(self):
# pretend a key was pressed, in order to unblock things
self.inject(self.ABORT_KEY)
def inject(self, key):
# fake a key press and release
if not self._changes.full():
self.key_pressed = ''
self._changes.put_nowait(key)
self._changes.put_nowait('')
def _key_event(self, key):
if key != self.key_pressed:
# annouce change
self.key_pressed = key
if self._changes.full():
# no space, but do a "all up" and the new event
print('Q overflow')
self._changes.get_nowait()
self._changes.get_nowait()
if key != '':
self._changes.put_nowait('')
self._changes.put_nowait(key)
self.last_event_time = utime.ticks_ms()