백준 알고리즘 10917번 Your life(python)

기본적인 BFS 문제이다.

import sys
from collections import deque

def bfs(node):
    q = deque()
    q.append(node)
    check[node] = 0
    while q:
        node = q.popleft()
        for n in graph[node]:
            if check[n] == -1:
                q.append(n)
                check[n] = check[node]+1

N, M = map(int, sys.stdin.readline().split())
graph = [[] for _ in range(N+1)]
for _ in range(M):
    u, v = map(int, sys.stdin.readline().split())
    graph[u].append(v)
    graph[v].append(u)
check = [-1]*(N+1)
bfs(1)
print(check[N] if check[N] >= 0 else -1)