Randomized k-cut

Splits an undirected graph into k groups by merging the ends of random edges until k groups are left, and cuts the edges between them.

Time complexity O(V·E), gograph function partition.RandomizedKCut.

gograph picks the edges to contract at random, so the cut can change each time the server restarts.

Office network

Switches and rooms in a four-team office, wired through a core switch.

An undirected graph with 13 vertices and 16 edges.

Split the office network into 3 parts and try to cut as few cables as possible.

Use it in Go

cut, err := partition.RandomizedKCut(g, 3)
if err != nil {
	return err
}
for _, group := range cut.Supernodes {
	var members []string
	for _, v := range group {
		members = append(members, v.Label())
	}
	fmt.Println(members)
}
for _, e := range cut.CutEdges {
	fmt.Println(e.Source().Label(), e.Destination().Label())
}

Example graphs

• Friend groups, 12 vertices and 21 edges
• Office network, 13 vertices and 16 edges
• Maze, 30 vertices and 31 edges
• Karate club, 34 vertices and 78 edges

More in Partitioning

• Maximal cliques: Finds every group of vertices that are all adjacent to each other and can't take one more vertex.
• Girvan-Newman: Splits an undirected graph into k communities by removing, one at a time, the edge that the most shortest paths cross.

All algorithms