답안

graph = {
        'A': set(['B', 'C', 'E']),
        'B': set(['A']),
        'C': set(['A']),
        'D': set(['E', 'F']),
        'E': set(['A', 'D']),
        'F': set(['D'])
}

def dfs(graph, start):
    visited = []
    stack = [start]

    while stack:
        n = stack.pop()
        if n not in visited:
            visited.append(n)
            stack += graph[n] - set(visited)
    return visited

print(dfs(graph, 'E'))

#tree 풀이

tree = {
        'A': ['B', 'C', 'E'],
        'B': ['A'],
        'C': ['A'],
        'D': ['E', 'F'],
        'E': ['A', 'D'],
        'F': ['D']
}

def dfs(data, start):
    visited = []
    stack = [start]

    pass

    return visited

print(dfs(tree, 'E'))