DFS

from collections import deque

visited = set()

def bfs(graph, root):
    print(root)
    visited.add(root)
    for i in graph[root]:
        if i in visited:
            continue
        else:
            bfs(graph, i)            
#while

graph = {
    1: [2, 3, 8],
    2: [7],
    3: [4],
    4: [5],
    5: [],
    6: [],
    7: [6],
    8: []
}

bfs(graph, 1)

# 출력
# 1
# 2
# 3
# 8
# 7
# 4
# 6
# 5