Solved Kruskal's tree printing bug

Author: S-M-J-I

src/spanning_trees/DisjointSet.java

@@ -8,15 +8,12 @@
 
 public class DisjointSet {
 
- private int nodeCount; /** track how many nodes do we have */
- private int setCount; /** track how many sets do we have */
+ private int nodeCount = 0; /** track how many nodes do we have */
+ private int setCount = 0; /** track how many sets do we have */
  private List<Node> representatives;
 
  public DisjointSet(List<Vertex> vertices) {
  this.representatives = new ArrayList<>(vertices.size());
- this.nodeCount = 0;
- this.setCount = 0;
-
  makeSets(vertices);
  }
 
@@ -35,7 +32,7 @@ private void makeSets(List<Vertex> vertices) {
  * we increase the count of nodes and dj sets
  * */
  private void makeSet(Vertex v) {
- Node node = new Node(0, representatives.size(), null);
+ Node node = new Node(nodeCount, representatives.size(), null);
  v.setNode(node);
  this.representatives.add(node);
  this.setCount++;

src/spanning_trees/kruskals/Kruskals.java

@@ -16,8 +16,8 @@ public void run(List<Vertex> vertices, List<Edge> edges) {
 
  Collections.sort(edges);
 
- for(Edge edge : edges) {
 
+ for(Edge edge : edges) {
  Vertex u = edge.getStartVertex();
  Vertex v = edge.getTargetVertex();
 
@@ -27,9 +27,8 @@ public void run(List<Vertex> vertices, List<Edge> edges) {
  }
  }
 
-
  for(Edge edge : MST) {
- System.out.println(edge.getStartVertex()+" "+edge.getTargetVertex()+" -- ");
+ System.out.print(edge.getStartVertex()+" "+edge.getTargetVertex()+" -- ");
  }
 
  }

src/spanning_trees/kruskals/RunKruskals.java

@@ -9,16 +9,37 @@ public static void main(String[] args) {
  Vertex A = new Vertex("A");
  Vertex B = new Vertex("B");
  Vertex C = new Vertex("C");
+ Vertex D = new Vertex("D");
+ Vertex E = new Vertex("E");
+ Vertex F = new Vertex("F");
+ Vertex G = new Vertex("G");
+ Vertex H = new Vertex("H");
 
  List<Vertex> vertices = new ArrayList<>();
  vertices.add(A);
  vertices.add(B);
  vertices.add(C);
+ vertices.add(D);
+ vertices.add(E);
+ vertices.add(F);
+ vertices.add(G);
+ vertices.add(H);
 
  List<Edge> edgeList = new ArrayList<>();
- edgeList.add(new Edge(3, vertices.get(0), vertices.get(1))); // A - B
- edgeList.add(new Edge(2, vertices.get(0), vertices.get(2))); // A - C
- edgeList.add(new Edge(5, vertices.get(1), vertices.get(2))); // B - C
+ edgeList.add(new Edge(3, vertices.get(0), vertices.get(1)));
+ edgeList.add(new Edge(2, vertices.get(0), vertices.get(2)));
+ edgeList.add(new Edge(5, vertices.get(0), vertices.get(3)));
+ edgeList.add(new Edge(13, vertices.get(1), vertices.get(5)));
+ edgeList.add(new Edge(2, vertices.get(1), vertices.get(3)));
+ edgeList.add(new Edge(5, vertices.get(2), vertices.get(4)));
+ edgeList.add(new Edge(2, vertices.get(2), vertices.get(3)));
+ edgeList.add(new Edge(4, vertices.get(3), vertices.get(4)));
+ edgeList.add(new Edge(6, vertices.get(3), vertices.get(5)));
+ edgeList.add(new Edge(3, vertices.get(3), vertices.get(6)));
+ edgeList.add(new Edge(6, vertices.get(4), vertices.get(6)));
+ edgeList.add(new Edge(2, vertices.get(5), vertices.get(6)));
+ edgeList.add(new Edge(3, vertices.get(5), vertices.get(7)));
+ edgeList.add(new Edge(6, vertices.get(6), vertices.get(7)));
 
  Kruskals algorithm = new Kruskals();
  algorithm.run(vertices, edgeList);