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curriculum/challenges/english/blocks/learn-algorithm-design-by-building-a-shortest-path-algorithm/65578c17d54dfab65cd54b95.md

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--description--

Since the algorithm begins its assessment from the starting node, after creating the paths dictionary, you need to add the starting node to its own list in the paths dictionary.

Use the .append() method to append start to the paths[start] list.

--hints--

You should use the .append() method to append start to paths[start].

js
({ test: () =>  {
    const shortest = __helpers.python.getDef(code, "shortest_path");
    const {function_body} = shortest;
    assert(function_body.match(/^\s{4}paths\s*\[\s*start\s*\]\s*\.append\s*\(\s*start\s*\)/m));
  }
})

--seed--

--seed-contents--

py
my_graph = {
    'A': [('B', 3), ('D', 1)],
    'B': [('A', 3), ('C', 4)],
    'C': [('B', 4), ('D', 7)],
    'D': [('A', 1), ('C', 7)]
}
--fcc-editable-region--
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}
    
    print(f'Unvisited: {unvisited}\nDistances: {distances}')
    
shortest_path(my_graph, 'A')
--fcc-editable-region--