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Exercise

Shortest Path II

Now that you've got the code for checking whether the destination node is present in neighbors, next up, you're going to extend the same function to write the code for the condition where the destination node is not present in the neighbors.

All the code you need to write is in the else condition; that is, if node2 is not in neighbors.

Instructions
100 XP
  • Using the .add() method, add the current node node to the set visited_nodes to keep track of what nodes have already been visited.
  • Add the neighbors of the current node node that have not yet been visited to queue. To do this, you'll need to use the .extend() method of queue together with a list comprehension. The .extend() method appends all the items in a given list.
    • The output expression and iterator variable of the list comprehension are both n. The iterable is the list neighbors, and the conditional is if n is not in the visited nodes.