Graphs · routine

Who can I reach?

A graph is a dictionary from each place to a list of its neighbours: {"a": ["b"], "b": ["c"], "c": []}.

Write reachable(graph, start) returning a list (any order) of every place you can get to from start, including start itself. Graphs can have loops — do not walk forever.

right answers
arguments left as they should be

def reachable(graph, start):
    found = [start]
    for n in graph[start]:
        found.append(n)
    return found

Run adds print(reachable({"a": ["b"], "b": ["c"], "c": []}, "a")) after your code, to try it.

Stuck on the idea rather than the code? The Graphs lesson walks through it.