I wrote a little program in JavaFX which displays a path of neighbouring open tiles going from top to bottom. It should simulate a percolation.

The algorithm iterates through the whole grid (every tile) populating a list with tiles that have a continuous connection to the top. It all works somewhat. My concern however is that it probably is highly inefficient and I don’t really know how to improve said efficiency as we didn’t learn anything of that sort in my school.

burnt is just another ArrayList initialised as a member variable.

GitHub link

public void searchCluster(Grid grid){     Node[][] array = grid.getNodeArray();     ArrayList<Node> tmpBurnt = new ArrayList();     LinkedList<Node> tmpSave = new LinkedList();     Node left;     Node right;     Node below;      for(Node n : array[0]){         if(n.isSet()){             tmpBurnt.add(n);         }     }      for(;;){         if(tmpBurnt.isEmpty()){             return;         }         for(Node n : tmpBurnt){             //-----check left--------             if(n.getX() > 0){                 left = array[n.getY()][n.getX() - 1];                 if(left.isSet() && !tmpBurnt.contains(left) && !this.burnt.contains(left)){                     tmpSave.add(left);                 }             }             //-----check right--------             if(n.getX() < array[n.getY()].length - 1){                 right = array[n.getY()][n.getX() + 1];                 if(right.isSet() && !tmpBurnt.contains(right) && !this.burnt.contains(right)){                     tmpSave.add(right);                 }             }             //-----check below--------             if(n.getY() < array.length - 1){                 below = array[n.getY() + 1][n.getX()];                 if(below.isSet() && !tmpBurnt.contains(below) && !this.burnt.contains(below)){                     tmpSave.add(below);                 }             }         }         for(Node n : tmpBurnt){             this.burnt.add(n);         }         tmpBurnt.clear();         for(Node n : tmpSave){             tmpBurnt.add(n);         }         tmpSave.clear();     } }