[백준] 1260번 DFS와 BFS (Python3)

import sys

N, M, V = map(int,sys.stdin.readline().split())

nodes = []

for node in range(N+1):
    nodes.append([])

for _ in range(M):
    [v1, v2] = map(int,sys.stdin.readline().split())
    nodes[v1].append(v2)
    nodes[v2].append(v1)

for subList in nodes:
    subList.sort()

dfsCheck = [0]*(N+1)

def dfs(ans, start):
    if dfsCheck[start] == 1:
        return
    dfsCheck[start] = 1
    ans.append(start)
    for i in nodes[start]:
        if dfsCheck[i] == 0:
            dfs(ans, i)

dfsAnswer = []
dfs(dfsAnswer, V)
print(*dfsAnswer)

bfsCheck = [0]*(N+1)

def bfs(ans, start):
    que = []
    que.append(start)

    while len(que) > 0:
        index = que.pop(0)
        bfsCheck[index] = 1
        ans.append(index)
        # print("ans :", ans)
        for node in nodes[index]:
            if bfsCheck[node] == 1:
                continue
            else:
                bfsCheck[node] = 1
                que.append(node)


bfsAnswer = []
bfs(bfsAnswer, V)
print(*bfsAnswer)