search.py 文件源码

def dfs(g: Graph, current: Vertex, condition: Test,
        visited: Set = None) -> Optional[Vertex]:

    visited = visited or set()

    if current in visited:
        return None

    visited.add(current)

    if condition(current):
        return current

    for n in g.neighbors(current):
        v = dfs(g, n, condition, visited)

        if v is not None:
            return v

    return None