Go: package main

import (
	"container/list"
	"fmt"
	"bufio"
	"os"
	"strconv"
)

const (
	N   = 100
	INF = 1 << 21
)

var (
	n        int
	adj      [N][N]int
	distance [N]int
)

func BFS(start int) {
	q := list.New()
	q.PushBack(start)
	for i := 0; i < n; i++ {
		distance[i] = INF
	}
	distance[start] = 0
	u := 0
	for q.Len() != 0 {
		u = q.Remove(q.Front()).(int)
		for v := 0; v < n; v++ {
			if adj[u][v] == 0 {
				continue
			}
			if distance[v] != INF {
				continue
			}
			distance[v] = distance[u] + 1
			q.PushBack(v)
		}
	}
	for i := 0; i < n; i++ {
		var d int
		if distance[i] == INF {
			d = -1
		} else {
			d = distance[i]
		}
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	var u, k, v int
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ = strconv.Atoi(scanner.Text())
		u -= 1
		scanner.Scan()
		k, _ = strconv.Atoi(scanner.Text())
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ = strconv.Atoi(scanner.Text())
			v -= 1
			adj[u][v] = 1
		}
	}
	BFS(0)
}

Python: import queue
from collections import namedtuple
T = namedtuple("T", "u d")

n = int(input())
path = dict()
ans = [-1] * (n + 1)

for i in range(n):
    a = [int(x) for x in input().split()]
    a.reverse()

    u, k = a.pop(), a.pop()
    path[u] = set()
    for j in range(k):
        path[u].add(a.pop())


def bfs(s):
    q = queue.Queue()
    q.put(s)

    while q.qsize() != 0:
        p = q.get()
        if p.d < ans[p.u] or ans[p.u] < 0:
            ans[p.u] = p.d
            for r in path[p.u]:
                q.put(T(r, p.d + 1))


bfs(T(1, 0))
for i in range(1, n + 1):
    print(i, ans[i])

Python: # -*- coding: utf-8 -*-
from collections import deque


class Graph:
    def __init__(self, n, adj_matrix):
        self.n = n
        self.adj_matrix = adj_matrix

    def show(self):
        for _ in self.adj_matrix:
            print(*_)

    def dfs(self):
        self.states = [2] * self.n
        self.d = [None] * self.n
        self.f = [None] * self.n
        self.time = 0

        for u in range(self.n):
            if self.states[u] == 2:
                self.dfs_visit(u)

    def dfs_visit(self, u):
        self.states[u] = 1
        self.time += 1
        self.d[u] = self.time

        for v, edge in [(v, edge) for v, edge in enumerate(self.adj_matrix[u])
                        if edge]:
            if self.states[v] == 2:
                self.dfs_visit(v)

        self.states[u] = 0
        self.time += 1
        self.f[u] = self.time

    def show_dfs(self, start=0):
        self.dfs()
        for i, (d, f) in enumerate(zip(self.d, self.f)):
            print(i + 1, d, f)

    def bfs(self, start):
        self.states = [1] * self.n
        self.dists = [float('inf')] * self.n

        queue = deque([start])
        self.dists[start] = 0
        while queue:
            u = queue.popleft()
            edges = self.adj_matrix[u]

            for v, edge in [(v, edge) for v, edge in enumerate(edges) if edge]:
                if v == start:
                    continue

                if self.dists[v] > self.dists[u] + 1:
                    self.dists[v] = self.dists[u] + 1
                queue.append(v)

        self.dists = [
            -1 if dist == float('inf') else dist for dist in self.dists
        ]

    def show_bfs(self, start=0):
        self.bfs(start=start)
        for i, dist in enumerate(self.dists):
            print(i + 1, dist)


if __name__ == '__main__':
    n = int(input())
    adj_matrix = [[0] * n for i in range(n)]
    for i in range(n):
        for v in input().split()[2:]:
            adj_matrix[i][int(v) - 1] = 1

    g = Graph(n, adj_matrix)
    g.show_bfs()

Python: from collections import deque
n = int(input())
G = [[] for _ in range(n)]
for i in range(n):
    u, k, *vs = map(int, input().split())
    u -= 1
    vs = list(map(lambda x: x - 1, vs))
    for v in vs:
        G[u].append(v)

dist = [-1] * n
dist[0] = 0
que = deque([0])

while len(que) > 0:
    now_v = que.popleft()
    now_dist = dist[now_v]
    next_vs = G[now_v]
    for next_v in next_vs:
        if dist[next_v] == -1:
            dist[next_v] = now_dist + 1
            que.append(next_v)

for i, x in enumerate(dist):
    print(i + 1, x)

Python: import queue


def bfs(g, s=1):
    global q

    dist = [-1] * len(g)
    dist[1] = 0
    q = queue.Queue()
    q.put(s)

    while not q.empty():
        v = q.get()
        if not G[v][1]:
            continue
        for vi in G[v][2:]:
            if dist[vi] >= 0:
                continue
            q.put(vi)
            dist[vi] = dist[v] + 1

    return dist


n = int(input())
G = [None]
for i in range(n):
    G.append(list(map(int, input().split())))

d = bfs(G)
for i in range(1, n + 1):
    print('%d %d' % (i, d[i]))

Python: import queue
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Python: # -*- coding: utf-8 -*-

import sys
import os
import math


N = int(input())

E = []
E.append([])
d = [-1] * (N + 1)

for i in range(N):
    lst = list(map(int, input().split()))
    nodes = lst[2:]
    E.append(nodes)
#print(E)

q = []
q.append(1)

visited = [False] * (N + 1)
d[1] = 0
visited[1] = True

while q:
    index = q.pop(0)

    # ???????????????????????´???
    for v in E[index]:
        if not visited[v]:
            q.append(v)
            d[v] = d[index] + 1
            visited[v] = True

#print(d)
for i in range(1, N + 1):
    print(i, d[i])

Python: 
import queue

WHITE = 0
GRAY = 1
BLACK = 2

NIL = -1
INF = 1000000000


def bfs(u):
    global Q
    Q.put(u)
    for i in range(n):
        d[i] = NIL
    d[u] = 0
    while not Q.empty():
        u = Q.get()
        for v in range(n):
            if (m[u][v] == 1) and (d[v] == NIL):
                d[v] = d[u] + 1
                Q.put(v)
n = int(input())

m = [[0 for i in range(n + 1)] for j in range(n + 1)]
vid = [0] * n
d = [0] * n
f = [0] * n
Q = queue.Queue()
color = [WHITE] * n
time = 0
nt = [0] * n

tmp = []
for i in range(n):
    nums=list(map(int,input().split()))
    tmp.append(nums)
    vid[i] = nums[0]

for i in range(n):
    for j in range(tmp[i][1]):
        m[i][vid.index(tmp[i][j + 2])] = 1

bfs(0)

for i in range(n):
    print(vid[i], d[i])

Python: from collections import deque
N = input()
d = [float('inf')] * N
m = [[0] * N for i in range(N)]
Q = deque([])

def bfs(s):
    Q.append(s)
    d[s] = 0

    while(len(Q) != 0):
        u = Q.popleft()
        for v in range(N):
            if (m[u][v] and  d[v] == float('inf')):
                d[v] = d[u] + 1
                Q.append(v)




if __name__ == '__main__':

    for i in range(N):
        v = map(int, raw_input().split())
        for j in v[2:]:
            m[i][j-1] = 1
    
    bfs(0)

    for i in range(N):
        if d[i] == float('inf'):
            d[i] = -1
        print (i+1), d[i]