ML Prep

Connected component with iterative DFS

Problem

Implement component(graph, start), returning the set of vertices reachable from start in an adjacency dictionary. Use an explicit stack.

Starter code

def component(graph, start):
    pass
Reveal answer or reference solution
def component(graph, start):
    stack = [start]
    seen = set()
    while stack:
        node = stack.pop()
        if node in seen:
            continue
        seen.add(node)
        stack.extend(graph.get(node, []))
    return seen

Public tests

  • component({1:[2],2:[1,3],3:[2],4:[]}, 1) → {1, 2, 3}
  • component({}, 5) → {5}

Local history

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