Coloring.MarkProvide a function for k-coloring a graph with integer marks. The provided function is more efficient that the one provided by functor Make above.
val coloring : G.t -> int -> unitcoloring g k colors the nodes of graph g using k colors, assigning the marks integer values between 1 and k.
The graph marks may be partially set before starting; the meaning of initial values is as follows:
k: a color already assignedk: a node to be ignoredval two_color : G.t -> unittwo_color g attemps to color g with colors 1 and 2.