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Edge Biconnected Component Count Tool

Count undirected vertex components after removing bridges, including isolated vertices; parallel edges and self-loops are preserved.

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Description

Traverse the undirected edge-indexed adjacency to identify bridges using discovery and low-link values, then count vertex components reachable without bridge edges.

Connected components partition a graph by reachability. Removing bridges creates an edge-connectivity partition; this differs from vertex-biconnected decomposition, which concerns articulation vertices and has different blocks.

Traverse the undirected edge-indexed adjacency to identify bridges using discovery and low-link values, then count vertex components reachable without bridge edges.

When to use this tool

Use Edge Biconnected Component Count when you need a component or bridge-related count under the specified undirected graph model.

How to use the tool and how it works

  1. Enter vertices, sources, targets. Keep parallel arrays aligned. Use the units and conventions below.
  2. Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
  3. Read componentCount, bridgeCount. Use the output convention below.

Require distinct vertices and aligned sources and targets with every endpoint listed. Traverse the undirected edge-indexed adjacency to identify bridges using discovery and low-link values, then count vertex components reachable without bridge edges.1

Input fieldMeaning and unitsAccepted input
verticesVerticesRequired. Array of text; maximum UTF-16 length 8192; maximum items 256.
sourcesSourcesRequired. Array of text; maximum UTF-16 length 8192; maximum items 256.
targetsTargetsRequired. Array of text; maximum UTF-16 length 8192; maximum items 256.
Output fieldInterpretationReturned shape
componentCountNumber of vertex components after all bridges are removed, including isolated vertices.Required. Safe integer.
bridgeCountNumber of undirected edge records identified as bridges; parallel edges retain distinct identities.Required. Safe integer.
json
{
  "input": {
    "vertices": [
      "A",
      "B",
      "C"
    ],
    "sources": [
      "A",
      "B"
    ],
    "targets": [
      "B",
      "C"
    ]
  },
  "output": {
    "componentCount": 3,
    "bridgeCount": 2
  }
}

Limitations and assumptions

  • Parallel edges and loops are retained and isolated vertices count as components; this is edge-biconnected component counting after bridge removal, not vertex-biconnected block decomposition or directed connectivity.
  • Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.

Alternative or Complementary methods

Traverse the supplied graph for an independently derived partition. Use articulation-point and vertex-biconnected algorithms when vertex removal, rather than edge removal, is the relevant failure model.

References

  1. Calculation and input contract: graph/edge-biconnected-component-count — tool.io

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