construct/nppc three coloring

construct/nppc three coloring: a task in MathConstructOptimize-Envs-harbor (Harbor dataset). Graph with 15 vertices labelled 0..14 and edge list 0, 3 , 0, 5 , 0, 6 , 0, 11 , 0, 13 , 0, 14 , 1, 2 , 1, 4 , 1, 7 , 1, 13 , 2, 3 , 2, 6 , 2, 7 , 2, 10 , 3, 5 , 3, 9 , 3, 10 , 3, 12 , 4, 5 , 4, 6 , 4, 12…