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
Initially, all the rooms start locked (except for room
You can walk back and forth between rooms freely.
true if and only if you can enter every room.
We start in room 0, and pick up key 1.
We then go to room 1, and pick up key 2.
We then go to room 2, and pick up key 3.
We then go to room 3. Since we were able to go to every room, we return true.
Explanation: We can't enter the room with number 2.
1 <= rooms.length <= 1000
0 <= rooms[i].length <= 1000
- The number of keys in all rooms combined is at most