freeCodeCamp/curriculum/challenges/german/07-scientific-computing-with-python/learn-algorithm-design-by-building-a-shortest-path-algorithm/657891ab9c1903f4e55433ba.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
657891ab9c1903f4e55433ba	Schritt 39	20	step-39

--description--

Inside your new if block, delete pass and reassign the neighbor node distance to the sum of the neighbor node distance plus the distance of current.

--hints--

You should assign distance + distances[current] to the neighbor node distance inside your new if.

({ test: () =>  {
    const shortest = __helpers.python.getDef(code, "shortest_path");
    const {function_body} = shortest;    
    assert(function_body.match(/^(\s*)if\s+distance\s*\+\s*distances\s*\[\s*current\s*\]\s*<\s*distances\s*\[\s*node\s*\]\s*:\s*^\1\s{4}distances\s*\[\s*node\s*\]\s*=\s*distance\s*\+\s*distances\s*\[\s*current\s*\]/ms));
  }
})

--seed--

--seed-contents--

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)
        for node, distance in graph[current]:
--fcc-editable-region--
            if distance + distances[current] < distances[node]:
                pass
--fcc-editable-region--
    print(f'Unvisited: {unvisited}\nDistances: {distances}\nPaths: {paths}')

#shortest_path(my_graph, 'A')