Learn Algorithm Design by Building a Shortest Path Algorithm - Step 46

Python
1

Tell us what’s happening:

I’m making good progress and I’m on the Learning Algorithm Design module but I am stuck on this step, the instruction was simple - to delete ‘pass’ and assign ‘paths[current]’ to ‘paths[node]’ and I did just that but it won’t go through to the next step. I tried debugging and I just cant seem to find anything wrong

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)

# User Editable Region

    while unvisited:
        current = min(unvisited, key=distances.get)
        for node, distance in graph[current]:
            if distance + distances[current] < distances[node]:
                distances[node] = distance + distances[current]
                if paths[node][-1] == node:
                    paths[current] = paths[node]

# 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 46

2

remember that “assing a to b” means you put a on the rigth side of the assignment operator and b on the left side of the assignment operator

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