Graph_Traversal_Simulation

[MohsinMamoon]

Issue:
Undo works only when a node with no edges is created. If an edge is created (Between two existing nodes or new node with an edge), undo doesn't work but if, after this point, and edgeless node is created, then undo works as expected (able to undo until the start of the graph). Though it stops working again on creating an edge.

Steps to reproduce:

1. Go to http://cse01-iiith.vlabs.ac.in/exp7/Simulation.html?domain=Computer%20Science&lab=Data%20Structures
2. Click on 'Graph DFS and BFS'.
3. Click on 'Draw Graph'.
4. Click any where to create node 0.
5. Drag from node 0 to create node 1 which is neighbor of node 0 (out-edge from node 0).
6. Press undo.

Expected result:
Node 1 gets deleted.

Actual result:
Nothing Happens.

GIF