Question 15
Harry explores islands connected by logs, starting at the island marked “Bắt đầu” (Start). At every arrival he follows this procedure:
- If the island already has a sign, leave it unchanged. Otherwise place an arrow pointing to the island just left.
- If an adjacent island has no sign, go there.
- Otherwise inspect the current island's sign. If it is an arrow, follow it. If it is not an arrow, all islands have been explored.
The original printed procedure is retained here.
After all islands have been visited, the arrows are as shown.
Which island could Harry have explored last?
- If the island already has a sign, leave it unchanged. Otherwise place an arrow pointing to the island just left.
- If an adjacent island has no sign, go there.
- Otherwise inspect the current island's sign. If it is an arrow, follow it. If it is not an arrow, all islands have been explored.
The original printed procedure is retained here.
After all islands have been visited, the arrows are as shown.
Which island could Harry have explored last?