construct/nppc three coloring

construct/nppc three coloring: a task in MathConstructOptimize-Envs-harbor (Harbor dataset). Graph with 60 vertices labelled 0..59 and edge list 0, 3 , 0, 10 , 0, 24 , 0, 30 , 0, 39 , 0, 41 , 0, 44 , 0, 48 , 1, 7 , 1, 21 , 1, 22 , 1, 33 , 1, 34 , 1, 39 , 2, 12 , 2, 43 , 2, 49 , 3, 13 , 3, 48 , 3…