841. Keys and Rooms

https://leetcode.com/problems/keys-and-rooms/

Python

DFS

class Solution:
    def canVisitAllRooms(self, rooms: List[List[int]]) -> bool:
        all_rooms = set(range(len(rooms)))
        seen = set([0])

        def dfs(room_id):
            for key in rooms[room_id]:
                if key not in seen:
                    seen.add(key)
                    dfs(key)
        dfs(0)

        return not bool(all_rooms - seen)