MathCastle
Graph TheoryMediumDirected Graphs and Network Flows

Directed Graphs and Network Flows · Medium problem

A digraph has vertices 1,2,3,41,2,3,4 and arcs 1→21\to2, 2→12\to1, 3→43\to4, 4→34\to3, 1→31\to3, 2→32\to3, 2→42\to4. How many arcs does the condensation of this digraph have?