Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type vertexId int

type vertex struct {
	id vertexId
	visitedAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		visitedAt: -1,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.visitedAt >= 0
}

func bfs(id vertexId, vqueue []vertexId, vertices []vertex) {
	vertex := &vertices[id-1]
	for _, vid := range vertex.adjs {
		if !vertices[vid-1].isVisited() {
			(&vertices[vid-1]).visitedAt = vertex.visitedAt+1
			vqueue = append(vqueue, vid)
		}
	}
	if len(vqueue) > 0 {
		nextId := vqueue[0]
		nextVqueue := vqueue[1:]
		bfs(nextId, nextVqueue, vertices)
	}
}

func solveBfs(vertices []vertex) {
	vertex := &vertices[0]
	vertex.visitedAt = 0
	vqueue := make([]vertexId, 0)
	bfs(vertex.id, vqueue, vertices)
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveBfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d\n", vertices[i].id, vertices[i].visitedAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

Python: N= int(input())
E = [input().split()[2:] for _ in range(N)]
frag, T, L,Q = [0]*N, [0]*N,[0] + [-1]*N, [0]
frag[0] = 1
def func(ide):
    for i in E[ide]:
        i = int(i) - 1
        if L[i] < 0 :frag[i] = 1;L[i] = L[ide] +1 ;Q.append(i) 
        else:return

while Q:top = Q.pop();func(top)

for i in range(N):print(i + 1 ,int(L[i]))

Python: import queue

n = int(input())
graph = []
for _ in range(n):
    line = list(map(int, input().split()))
    graph.append([v - 1 for v in line[2:]])

q = queue.Queue()
q.put(0)
dist = [-1] * n
dist[0] = 0

while True:
    v = q.get()
    for next_v in graph[v]:
        if dist[next_v] == -1: 
            q.put(next_v)
            dist[next_v] = dist[v] + 1

    if q.empty():
        break

for i in range(n):
    print(i + 1, dist[i])

Python: n = int(input())

adj = [None]
for i in range(n):
    adj_i = list(map(int, input().split()[2:]))
    adj.append(adj_i)

isSearched = [None] + [False] * n

distance = [None] + [-1] * n

import collections

def bfs(u):
    isSearched[u] = True
    distance[u] = 0
    edge = collections.deque()
    edge.append(u)
    while edge:
        c_e = edge.popleft()
        for n_e in adj[c_e]:
            if not isSearched[n_e]:
                isSearched[n_e] = True
                distance[n_e] = distance[c_e] + 1
                edge.append(n_e)


bfs(1)

for i, x in enumerate(distance[1:], start=1):
    print(i, x)

Python: n = int(input())
g = [input().split()[2:] for _ in range(n)]

from collections import deque
que = deque()
que.append(0)
d = [0] + [-1] * n

while que:
    u = que.popleft()

    for v in g[u]:
        v = int(v) - 1

        if d[v] < 0:
            d[v] = d[u] + 1
            que.append(v)

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

"""
・グラフの数を受け取る
・グラフを作る．今回は隣接リストで必要な部分だけを残してリスト化する
・キュー用の配列を作る（これはなんでもいい．普通のリストでも可）．そのキューには1番初めのスタート位置を入れておく
・最短距離を置いておくリストを用意
・queの中身がなくなるまで続ける
・queの中身を取り出して，それにくっついてるノードを全て舐めていく．int方で入力を受け取っていないから注意．1-indexを0-indexに変える．
・もしそこにまだBFSが訪れていなかったら，そこに前回の場所から1足した物を代入
・探索用のqueに追加しておく．追加しておくことでまたそのノードとつながってるところを調べることができる
・最後は出力．全てのノードの最短距離を出力
"""

Python: from collections import deque

n = int(input())
g = [None] * n
visited = [0] * n
dist = [-1] * n
Q = deque()

while n:
    l = list(map(int, input().split()))
    g[l[0]-1] = [i-1 for i in l[2:]]
    n -= 1

Q.append((0, 0)) 
visited[0] = 1

while Q:
    i, d = Q.popleft()         
    dist[i] = d
    for c in g[i]:
        if not visited[c]:
            visited[c] = 1
            Q.append((c, d+1))

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

Python: from collections import deque
if __name__ == "__main__":
    n = int(input())
    graph = []
    for _ in range(n):
        v, k, *tmp = map(int, input().split())
        for j in range(len(tmp)):
            tmp[j] -= 1
        graph.append(tmp)
    visited = [False] * n
    qu = deque()
    qu.appendleft((0, 0))
    ans = [-1] * n
    visited[0] = True

    while qu:
        now, dis = qu.pop()
        ans[now] = dis

        for nei in graph[now]:
            if not visited[nei]:
                visited[nei] = True
                qu.appendleft((nei, dis + 1))
    for i in range(n):
        print(i+1,ans[i])

Python: from collections import deque

n = int(input())
li = [list(map(int, input().split())) for _ in range(n)]

graph = [[] for _ in range(n+1)]
for u, k, *v in li:
    for i in v:
        graph[u].append(i)

ans = [-1] * (n+1)

ans[1] = 0
stack = deque([1])
while stack:
    num = stack.popleft()

    for s in graph[num]:
        if ans[s] == -1:
            stack.append(s)
            ans[s] = ans[num] + 1
            
for i, v in enumerate(ans[1:]):
    print(i+1, v)

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


if __name__ == '__main__':

    n = int(input())
    M = [[0 for i in range(n)] for j in range(n)]
    for _ in range(n):
        l = list(map(int, input().split(" ")))
        u = l[0]
        k = l[1]
        if k != 0:
            for v in l[2:]:
                M[u - 1][v - 1] = 1

    color = [0] * n
    d = [-1] * n
    Q = deque()

    def bfs(s):  # breadth-first search
        color[s] = 1
        d[s] = 0
        Q.append(s)

        while len(Q) != 0:
            u = Q.popleft()
            for v in range(n):
                if M[u][v] == 1 and color[v] == 0:
                    color[v] = 1
                    d[v] = d[u] + 1
                    Q.append(v)
            color[u] = 2

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

Python: import sys
input = lambda: sys.stdin.readline().rstrip() 
from collections import deque

def resolve():
    n = int(input())
    ukv = [list(map(int, input().split())) for _ in range(n)]

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

    que.append(0)
    dist[0] = 0
    while len(que)>0:
        v = que.popleft()
        for i in ukv[v][2:]:
            if dist[i-1]==-1:
                que.append(i-1)
                dist[i-1] = dist[v]+1

    for i in range(n):
        print(i+1, dist[i])

if __name__ == '__main__':
    resolve()

Python: #!/usr/bin/env python3
import sys
input = lambda: sys.stdin.readline()[:-1]
sys.setrecursionlimit(10**8)
from collections import deque

n=int(input())
G=[0]*n
memo=[0]*n
dis=[0]*n
dis[0]=1
que=deque()
que.append((0,1))

for i in range(n):
    inp=tuple(map(int,input().split()))
    G[inp[0]-1]=inp[2:]

while que:
    vertex,d=que.popleft()
    for v in G[vertex]:
        if not dis[v-1]:
            dis[v-1]=d+1
            que.append((v-1,d+1))
        

for i in range(n):
    print(i+1,dis[i]-1)

Python: def MAIN():
    n = int(input())
    li = [[] for _ in range(n + 1)]
    ans = [[i, 0] for i in range(n + 1)]
    for _ in range(n):
        u, k, *v = map(int, input().split())
        li[u] = v
    dp = [1]
    while dp:
        u = dp.pop()
        for v in li[u]:
            if ans[v][1] == 0:
                ans[v][1] = ans[u][1] + 1
                dp.append(v)
    for d in ans[1:]:
        print(*d)
MAIN()