Learn Algorithm Design by Building a Shortest Path Algorithm - Step 43

Python
1

Tell us what’s happening:

I can’t find out the mistake in my code. I don’t understand why it still not passes

Your code so far

my_graph = {
    'A': [('B', 3), ('D', 1)],
    'B': [('A', 3), ('C', 4)],
    'C': [('B', 4), ('D', 7)],
    'D': [('A', 1), ('C', 7)]
}

def shortest_path(graph, start):
    unvisited = list(graph)
    distances = {node: 0 if node == start else float('inf') for node in graph}
    paths = {node: [] for node in graph}
    paths[start].append(start)
    
    while unvisited:
        current = min(unvisited, key=distances.get)

# User Editable Region

        for node, distance in graph[current]:
            pass
            if distance + distances[current] < distances[node]:
              pass

# User Editable Region

    print(f'Unvisited: {unvisited}\nDistances: {distances}\nPaths: {paths}')
    
#shortest_path(my_graph, 'A')

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Challenge Information:

Learn Algorithm Design by Building a Shortest Path Algorithm - Step 43

2

You only need to use pass if you have nothing else in the body after the colon:

3
  • The pass statements are placeholders and should be replaced with actual logic to update distances and paths.
  • You need to correctly update the distances and paths inside the loop.
  • You should remove the current node from the unvisited list once it’s processed.
4

that’s what happens in the following steps, if you do all that in this step the tests are not going to accept it

5

@tapajana01 Nope, that advice is incorrect, unfortunately. Take a closer look at the instructions please:

Use the pass keyword to temporarily fill the body of the if.

6

so what do I need to do next

7

Seems like you have an extra pass added in the body of for.