[ Graph Traversal ]

There is a group of islands connected by bridges in such a way that from any island, you can reach any other island. A tourist visited all the islands, crossing each bridge exactly once. He visited the Triplet Island three times. How many bridges lead to the Triplet Island if the tourist

a) did not start or end on it?

b) started on it but did not end on it

c) started and ended on it?
a) If the Triple tourist entered the island 3 times and exited 3 times, that means he used 6 bridges.

b) In this case, the tourist entered the island twice, but exited three times.

## Answer

a) 6 bridges; b) 5 bridges; c) 4 bridges.