Given a graph G, a Hamiltonian circuit (a.k.a. Hamiltonian cycle) is a circuit that visits every vertex exactly once.  This problem is to find a Hamiltonian circuit or determine that there are none.

The only difference between the 2 problems is that problem 9 is a directed graph, and problem 10 is an undirected graph.

Here's a video: https://youtu.be/AamHZhAmR7o