Class Cycle

  • public class Cycle
    extends Object
    The Cycle class represents a data type for determining whether an undirected graph has a simple cycle. The hasCycle operation determines whether the graph has a cycle and, if so, the cycle operation returns one.

    This implementation uses depth-first search. The constructor takes Θ(V + E) time in the worst case, where V is the number of vertices and E is the number of edges. (The depth-first search part takes only O(V) time; however, checking for self-loops and parallel edges takes Θ(V + E) time in the worst case. Each instance method takes Θ(1) time. It uses Θ(V) extra space (not including the graph).

    For additional documentation, see Section 4.1 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

    Robert Sedgewick, Kevin Wayne
    • Constructor Detail

      • Cycle

        public Cycle​(Graph G)
        Determines whether the undirected graph G has a cycle and, if so, finds such a cycle.
        G - the undirected graph
    • Method Detail

      • hasCycle

        public boolean hasCycle()
        Returns true if the graph G has a cycle.
        true if the graph has a cycle; false otherwise
      • cycle

        public Iterable<Integer> cycle()
        Returns a cycle in the graph G.
        a cycle if the graph G has a cycle, and null otherwise
      • main

        public static void main​(String[] args)
        Unit tests the Cycle data type.
        args - the command-line arguments