Added stack and queue viewing for BFS and DFS

Author: luotn

js/simulate.js

@@ -321,6 +321,8 @@ function updateVisuals() {
                 const score = queueCell.score
                 if(score != -1)
                     CellReferences[algorithm][pos[1] * Grid.width + pos[0]].innerHTML = score
+                else
+                    CellReferences[algorithm][pos[1] * Grid.width + pos[0]].innerHTML = "0"
             })
 
             // Set searching cell to #FFFF00, filter generated by: https://codepen.io/sosuke/pen/Pjoqqp