Degeneracy Ordering

Problem

Compute a degeneracy (smallest-last) ordering of an undirected graph.

Repeatedly remove the node with the smallest current degree, breaking ties by smallest index, and record the removal order. Return the full ordering of n nodes. edges is a list of [u, v] pairs.

Hint

The largest degree seen during peeling is the graph degeneracy.

Test cases

case 1

in: [4,[[0,1],[1,2],[2,3]]]

expected: [0,1,2,3]

case 2

in: [4,[[0,1],[0,2],[0,3]]]

expected: [1,2,0,3]

case 3

in: [4,[[0,1],[0,2],[0,3],[1,2],[1,3],[2,3]]]

expected: [0,1,2,3]

case 4

in: [4,[[0,1],[1,2],[2,0],[2,3]]]

expected: [3,0,1,2]

Starter codePython

def degeneracy_ordering(n, edges):
    # Your code here
    pass

4 test cases · run your code against them in the editor