There are N rooms and you start in room 0. Each room has a distinct number in
0, 1, 2, ..., N-1, and each room may have some keys to access the next room.
Formally, each room i has a list of keys
rooms[i], and each key
rooms[i][j] is an integer in
[0, 1, ..., N-1] where
N = rooms.length. A key
rooms[i][j] = v opens the room with number v.
Initially, all the rooms start locked (except for room 0). You can walk back and forth between rooms freely.
true if and only if you can enter every room.
class Solution: def canVisitAllRooms(self, rooms): if len(rooms) <= 1: #guard for short or empty list return True key_inventory = set() # append only rooms_visited = set() #append while key_inventory - rooms_visited: # We have keys to rooms we have not seen chosen_room = (key_inventory - rooms_visited).pop() #choose the room keys = set(rooms[chosen_room]) # visit chosen room, get keys key_inventory |= keys # add keys found in room to inventory rooms_visited.add(chosen_room) # room has been visited if key_inventory >= set(range(len(rooms))): # Stop once we have a key for each room return True return False # We have no keys to rooms we have not seen, and we didnt have a key for each room
class Solution: def __init__(self): self.visited = set() self.number_of_rooms = 0 def dfs(self, rms, rm): if rm not in self.visited: print(rm) self.visited.add(rm) for room_key in rms[rm]: if room_key < self.number_of_rooms: self.dfs(rms, room_key) def canVisitAllRooms(self, rooms) -> bool: if rooms: self.number_of_rooms = len(rooms) self.dfs(rooms, 0) if len(self.visited) != self.number_of_rooms: return False else: return True else: print("No Rooms to Enter") return False