Traversing Directed Eulerian Mazes.

Two algorithms for threading directed Eulerian mazes are described. Each of these algorithms is performed by a traveling robot whose control is a finite-state automaton. Each of the algorithms puts one pebble in one of the exits of every vertex. These pebbles indicate an Eulerian cycle of the maze. The simple algorithm performs O (| V | ċ | E |) edge traversals, while the advanced one traverses every edge three times. Both algorithms use memory of size O (log d out (υ)) in every vertex υ.