Block-Cut Tree Size

Problem

Compute the size of the block-cut tree of an undirected graph with n nodes.

Run a DFS that tracks discovery and low-link values, pushing tree edges on a stack and popping a block whenever low[child] >= disc[parent]; nodes that start blocks are articulation points. Return [block_count, articulation_count, total_nodes] where total_nodes is blocks plus articulation points.

Hint

The block-cut tree alternates block nodes and articulation points.

Test cases

case 1

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

expected: [2,1,3]

case 2

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

expected: [1,0,1]

case 3

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

expected: [3,1,4]

case 4

in: [5,[[0,1],[1,2],[2,0],[2,3],[3,4],[4,2]]]

expected: [2,1,3]

case 5

in: [3,[]]

expected: [0,0,0]

Starter codePython

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

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