MathCastle
Graph TheorySuperchallengeEulerian and Hamiltonian Graphs

Eulerian and Hamiltonian Graphs · Superchallenge problem

Six stations 0,…,50,\ldots,5 sit in a loop with roads 01:501{:}5, 12:612{:}6, 23:423{:}4, 34:534{:}5, 45:945{:}9, 50:750{:}7 (going around), plus one direct shortcut road 03:2503{:}25 (no other roads exist). A crew based at 00 must clear every road and return to 00, duplicating roads where cheapest. What is the minimum total distance?