data_structures_free

net/datastructures/ComponentsDFS.java

@@ -0,0 +1,20 @@
+package net.datastructures;
+import java.util.Iterator;
+
+//begin#fragment CC
+/** This class extends DFS to compute the connected components of a graph. */
+public class ComponentsDFS<V, E> extends DFS<V, E, Object, Integer> {
+  protected Integer compNumber; // Connected component number
+  protected Object COMPONENT = new Object(); // Connected comp. selector
+  protected void setup() { compNumber = 1; }
+  protected void startVisit(Vertex<V> v) { v.put(COMPONENT, compNumber);}
+  protected Integer finalResult(Integer dfsResult) { 
+    for (Vertex<V> v : graph.vertices()) // check for any unvisited vertices
+      if (v.get(STATUS) == UNVISITED) { 
+        compNumber += 1;  // we have found another connected component
+	dfsTraversal(v);  // visit all the vertices of this component
+      }
+    return compNumber;
+  }
+}
+//end#fragment CC