Eulerian cycle
Definition
A eulerian cycle is an ordinary cycle in a directed or undirected graph that contains each edge/arc exactly once. Redundant information for clarification: In the directed case, each arc must have forward orientatin on the cycle.
Input
A strongly connected directed or connected undirected graph.
Output
A Eulerian cycle as an alternating sequence of nodes and edges/arcs or, alternatively, the (correct) message that no such cycle exists.