# Dijkstra Algorithm - Could not run sketch

**URL:** https://discourse.processing.org/t/dijkstra-algorithm-could-not-run-sketch/18943
**Category:** Coding Questions
**Created:** [March 23, 2020, 6:40pm UTC](https://discourse.processing.org/t/dijkstra-algorithm-could-not-run-sketch/18943 "2020-03-23T18:40:19Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![Aloxion](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@Aloxion](https://discourse.processing.org/u/Aloxion)
#### Post date: [March 23, 2020, 6:40pm UTC](https://discourse.processing.org/t/dijkstra-algorithm-could-not-run-sketch/18943/1 "2020-03-23T18:40:19Z")

</div>

Full ERROR code:

> IndexOutOfBoundsException: Index: 109, Size: 88  
> Could not run the sketch (Target VM failed to initialize).

So im having a problem with my program/project. I am a bit new, so if you have any other suggestions as to how i can improve please tell.

What i think it is:  
I think its a problem with my Edge. I can normally run the sketch without the code

```auto
edges.add( new Edge((Node1)nodes1.get(56), (Node1)nodes1.get(55))); 
edges.add( new Edge((Node1)nodes1.get(55), (Node1)nodes1.get(69))); 
edges.add( new Edge((Node1)nodes1.get(55), (Node1)nodes1.get(109)));

```

The problem comes when i have id nodes 100+

Code:

```auto
import java.util.List;

ArrayList nodes1;
ArrayList edges;

PImage img; 

void setup(){
 size(1920,1080);
 img = loadImage("kort.png");
 
 nodes1 = new ArrayList();
 edges = new ArrayList();
 //1 , 2 , 3 , 4 , 5
 nodes1.add(new Node1(1065, 803, 0)); nodes1.add(new Node1(1000, 755, 1)); nodes1.add(new Node1(950, 698, 2)); nodes1.add(new Node1(874, 688, 3)); nodes1.add(new Node1(806, 638, 4));
 //6, 7, 8, 9, 10
 nodes1.add(new Node1(762, 579, 5)); nodes1.add(new Node1(778, 567, 6)); nodes1.add(new Node1(769, 498, 7)); nodes1.add(new Node1(772, 446, 8)); nodes1.add(new Node1(833, 431, 9)); 
 //11, 12, 13, 14, 15
 nodes1.add(new Node1(782, 373, 10)); nodes1.add(new Node1(818, 412, 11)); nodes1.add(new Node1(793, 384, 12)); nodes1.add(new Node1(893, 499, 13)); nodes1.add(new Node1(852, 564, 14));
 //16, 17, 18, 19 , 20
 nodes1.add(new Node1(967, 588, 15)); nodes1.add(new Node1(1019, 625, 16)); nodes1.add(new Node1(1082, 669, 17)); nodes1.add(new Node1(1122, 696, 18)); nodes1.add(new Node1(1109, 710, 19));
 //21,22,23,24,25
 nodes1.add(new Node1(1079, 681, 20)); nodes1.add(new Node1(1027, 774, 21)); nodes1.add(new Node1(1087, 752, 22)); nodes1.add(new Node1(1182, 703, 23)); nodes1.add(new Node1(1131, 680, 24)); 
 //26, 27, 28, 29, 30
 nodes1.add(new Node1(1090, 660, 25)); nodes1.add(new Node1(771, 387, 26)); nodes1.add(new Node1( 955, 399, 27)); nodes1.add(new Node1( 885, 320, 28)); nodes1.add(new Node1(766, 361, 29)); 
 //31, 32, 33, 34, 35
 nodes1.add(new Node1( 782, 300, 30)); nodes1.add(new Node1( 813, 247, 31)); nodes1.add(new Node1( 831, 370, 32)); nodes1.add(new Node1( 936, 433, 33)); nodes1.add(new Node1( 774, 686, 34));
//36, 37, 38, 39, 40
nodes1.add(new Node1( 908, 745, 35)); nodes1.add(new Node1( 927, 694, 36)); nodes1.add(new Node1( 1036, 572, 37)); nodes1.add(new Node1( 1097, 514, 38)); nodes1.add(new Node1(1042 , 459, 39));
//41, 42, 43, 44, 45
nodes1.add(new Node1( 1050, 334, 40)); nodes1.add(new Node1( 1010, 316, 41)); nodes1.add(new Node1( 996, 306, 42)); nodes1.add(new Node1( 981, 224, 43)); nodes1.add(new Node1( 973, 192, 44));
//46, 47, 48, 49, 50
nodes1.add(new Node1( 953, 157, 45)); nodes1.add(new Node1(1155, 572, 46)); nodes1.add(new Node1(1192, 601, 47)); nodes1.add(new Node1(1258, 471, 48)); nodes1.add(new Node1(1235, 642, 49)); 
//51, 52, 53, 54, 55
nodes1.add(new Node1(1079, 825, 50)); nodes1.add(new Node1(1055, 828, 51)); nodes1.add(new Node1(1053, 847, 52)); nodes1.add(new Node1(1047, 873, 53)); nodes1.add(new Node1(1093, 847, 54)); 
//56, 57, 58, 59, 60
nodes1.add(new Node1(1053, 923, 55)); nodes1.add(new Node1(1064, 949, 56)); nodes1.add(new Node1(981, 836, 57)); nodes1.add(new Node1(935, 818, 58)); nodes1.add(new Node1(890, 794, 59)); 
//61, 62, 63, 64, 65
nodes1.add(new Node1(1058, 250, 60)); nodes1.add(new Node1(1014, 188, 61)); nodes1.add(new Node1(1035, 178, 62)); nodes1.add(new Node1(902, 213, 63)); nodes1.add(new Node1(852, 284, 64)); 
//66, 67, 68, 69, 70
nodes1.add(new Node1(1020, 115, 65)); nodes1.add(new Node1(1139, 328, 66)); nodes1.add(new Node1(956, 763, 67)); nodes1.add(new Node1(1233, 401, 68)); nodes1.add(new Node1(1077, 909, 69));
//71, 72, 73, 74, 75
nodes1.add(new Node1(1105, 798, 70)); nodes1.add(new Node1(1133, 757, 71)); nodes1.add(new Node1(1294, 596, 72)); nodes1.add(new Node1(1321, 591, 73)); nodes1.add(new Node1(1351, 562, 74)); 
//Destination Nodes
   //1
  nodes1.add(new Node1(1115, 874, 100));
   //2
   nodes1.add(new Node1(1155,732, 101));
   //3
   nodes1.add(new Node1(939, 756, 102));
   //4
   nodes1.add(new Node1(1205, 400, 103));
   //5
   nodes1.add(new Node1(1079, 250, 104));
   //6
   nodes1.add(new Node1(893, 307, 105));
   //7
   nodes1.add(new Node1(808, 255, 106));
   //8
   nodes1.add(new Node1(767, 383, 107));
   //9
   nodes1.add(new Node1(1335, 540, 108));
   //10
   nodes1.add(new Node1(1044, 895, 109));
   //11
   nodes1.add(new Node1(1071, 973, 110));
   //12
   nodes1.add(new Node1(819, 619, 111));
   //13
   nodes1.add(new Node1(894, 523, 112));
//EDGES
//Start route
edges.add( new Edge((Node1)nodes1.get(56), (Node1)nodes1.get(55))); edges.add( new Edge((Node1)nodes1.get(55), (Node1)nodes1.get(69))); 

edges.add( new Edge((Node1)nodes1.get(55), (Node1)nodes1.get(109)));

}

void draw(){
 background(0);
 image(img, 0,0);
  textSize(26);
// text( "x: " + mouseX + " y: " + mouseY, mouseX + 2, mouseY );
 
  for(int i=0; i<nodes1.size(); i++){
    Node1 n = (Node1) nodes1.get(i);
    n.display();
  }
  for(int j=0; j<edges.size(); j++){
    Edge e = (Edge) edges.get(j);
    e.display();
  } 
}
 

class Node1 {
  int xpos, ypos;
  int id;
  Node1(int i){
    id = i;
    xpos = width/2;
    ypos = height/5;
  }
 
  Node1(int x, int y, int i){
    id = i;
    xpos = x;
    ypos = y;
   
  }
 
  void display(){
        smooth();
        fill(255);
            if(id >= 100){
              fill(0);
      ellipse(xpos, ypos, 10, 10);
     // text(""+id, xpos-10,ypos-10);
    }else{
    ellipse(xpos, ypos, 10, 10);
  // text(""+id, xpos-10,ypos-10);
    }
    
  }
}

class Edge {
  int idOr, idDest;
 
  Edge(Node1 or, Node1 dest){
    idOr = or.id;
    idDest = dest.id;
  }
 
  void display(){
        smooth();
    Node1 orig = (Node1) nodes1.get(this.idOr);
    Node1 dest = (Node1) nodes1.get(this.idDest); // Processing underline this line when the error is generated
    strokeWeight(1);
    stroke(255,0,0,100);
    line(orig.xpos,
         orig.ypos,
         dest.xpos,
         dest.ypos);
  }
}

```

---

<div class="post-metadata">

### Author: ![mcintyre](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/mcintyre/32/14561_2.png) [@mcintyre](https://discourse.processing.org/u/mcintyre)
#### Post date: [March 23, 2020, 8:13pm UTC](https://discourse.processing.org/t/dijkstra-algorithm-could-not-run-sketch/18943/2 "2020-03-23T20:13:04Z")

</div>

When you call the `get()` method of an `ArrayList`, you are asking the computer to return the element (`Node1` object) at an index (location). `ArrayList`s are 0-indexed, so `nodes1.get(109)` tries to return the non-existent 110th element, hence the `IndexOutOfBoundsException`.

One thought is to `add()` your `Node1` objects in order and let their indices serve as id’s. Another is to check out `HashMap`s in the [Processing reference](https://processing.org/reference/HashMap.html).

---

<div class="post-metadata">

### Author: ![Aloxion](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@Aloxion](https://discourse.processing.org/u/Aloxion)
#### Post date: [March 23, 2020, 8:26pm UTC](https://discourse.processing.org/t/dijkstra-algorithm-could-not-run-sketch/18943/3 "2020-03-23T20:26:24Z")

</div>

Okay! Thanks for replying.  
But if i called 108 instead of 109 would i then return the 109th element?  
I tried and dont think its the solution. ( Did i misunderstand?)

I have tried something that is similar to the “id” you were talking about and it seems to work now.

---

<div class="post-metadata">

### Author: ![mcintyre](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/mcintyre/32/14561_2.png) [@mcintyre](https://discourse.processing.org/u/mcintyre)
#### Post date: [March 23, 2020, 11:11pm UTC](https://discourse.processing.org/t/dijkstra-algorithm-could-not-run-sketch/18943/4 "2020-03-23T23:11:07Z")

</div>

Yep, you understood correctly. Glad to hear it’s working!