문제 : https://www.acmicpc.net/problem/1260

▶ 코드 ( 큐 ver. )

from collections import deque

n, m, v = map(int, input().split())

s = [[0]*(n+1) for i in range(n+1)]
visited = [0]*(n+1)

for _ in range(m):
    a, b = map(int, input().split())
    s[a][b] = 1
    s[b][a] = 1



def dfs(v):
    print(v, end=' ')
    visited[v] = 1
    for i in range(1, n+1):
        if visited[i] == 0 and s[v][i] == 1:
            dfs(i)

def bfs(v):
    dq = deque([v])
    visited[v] = 1
    while(dq):
        v = dq.popleft()
        print(v, end=' ')
        for i in range(1, n+1):
            if visited[i] == 0 and s[v][i] == 1:
                dq.append(i)
                visited[i] = 1
        



dfs(v)
print()
visited = [0]*(n+1) # visited 초기화 
bfs(v)