MathCastle
Graph TheoryEasyWalks, Paths and Connectivity

Walks, Paths and Connectivity · Easy problem

A triangle on vertices 1,2,31,2,3 has an extra vertex 44 attached only to vertex 11, and another extra vertex 55 attached only to vertex 22 (edges 12,23,31,14,2512,23,31,14,25). How many walks of length 22 are there from vertex 44 to vertex 55?