Class StrongConnectivityInspector<V,​E>


  • public class StrongConnectivityInspector<V,​E>
    extends java.lang.Object

    Complements the ConnectivityInspector class with the capability to compute the strongly connected components of a directed graph. The algorithm is implemented after "Cormen et al: Introduction to agorithms", Chapter 22.5. It has a running time of O(V + E).

    Unlike ConnectivityInspector, this class does not implement incremental inspection. The full algorithm is executed at the first call of stronglyConnectedSets() or isStronglyConnected().

    Since:
    Feb 2, 2005
    Author:
    Christian Soltenborn, Christian Hammer
    • Constructor Detail

      • StrongConnectivityInspector

        public StrongConnectivityInspector​(DirectedGraph<V,​E> directedGraph)
        The constructor of the StrongConnectivityInspector class.
        Parameters:
        directedGraph - the graph to inspect
        Throws:
        java.lang.IllegalArgumentException
    • Method Detail

      • getGraph

        public DirectedGraph<V,​E> getGraph()
        Returns the graph inspected by the StrongConnectivityInspector.
        Returns:
        the graph inspected by this StrongConnectivityInspector
      • isStronglyConnected

        public boolean isStronglyConnected()
        Returns true if the graph of this StronglyConnectivityInspector instance is strongly connected.
        Returns:
        true if the graph is strongly connected, false otherwise
      • stronglyConnectedSets

        public java.util.List<java.util.Set<V>> stronglyConnectedSets()
        Computes a List of Sets, where each set contains vertices which together form a strongly connected component within the given graph.
        Returns:
        List of Set s containing the strongly connected components
      • stronglyConnectedSubgraphs

        public java.util.List<DirectedSubgraph<V,​E>> stronglyConnectedSubgraphs()

        Computes a list of DirectedSubgraphs of the given graph. Each subgraph will represent a strongly connected component and will contain all vertices of that component. The subgraph will have an edge (u,v) iff u and v are contained in the strongly connected component.

        NOTE: Calling this method will first execute stronglyConnectedSets(). If you don't need subgraphs, use that method.

        Returns:
        a list of subgraphs representing the strongly connected components