class GraphBuilder
{
  public ArrayList vertices;
  public ArrayList edges;
  private PFont label; 
  private int numOfVertices;  

  GraphBuilder(int n)
  {
    numOfVertices = n;  
    label = loadFont("mono12.vlw");
    vertices = new ArrayList();
    edges = new ArrayList();
    textFont(label, 12);
  }
  public void build()
  {
    int currentVertex = 0;
    for(int i = 0; i < numOfVertices; i++)
    {
      vertices.add(new Vertex(random(20, width-20), random(20, height-20), "V"+i));
      Vertex v = (Vertex) vertices.get(i);
    }
    while(currentVertex < numOfVertices)    //first measure n weights, then n-1 weights and so on.
    {
      for(int i = currentVertex; i < numOfVertices-1; i++)
      {
        Edge e = new Edge((Vertex)vertices.get(currentVertex), (Vertex)vertices.get(i+1));
        edges.add(e);
      }
      currentVertex++;
    }
    Collections.sort(edges);              //sort the edges so edges with smaller weights are first
  }
  
  public String toString()
  {
    return "Vertices: " + vertices.size() + "\nEdges: " + edges.size(); 
  }
  
  public void drawGraph()
  {
    smooth();
    fill(255, 255, 255, 50);
    stroke(255, 255, 255, 50); 
    strokeWeight(3);   
    if(edges.size() > 0)
    {
      for(int i = 0; i < numOfVertices; i++)
      {
        Vertex v = (Vertex) vertices.get(i);
        ellipse(v.x, v.y, 5, 4);                                  
        fill(255, 255, 255, 255);
        text("V"+i, v.x-5, v.y-5);
      }
      for(int j = 0; j < edges.size(); j++)
      {
        Edge e = (Edge)edges.get(j);
        stroke(255, 255, 255, 10);
        strokeWeight(0.5);
        line(e.v0.x, e.v0.y, e.v1.x, e.v1.y);
      }
    }
  }  
}