Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

Python: from collections import deque

N = 100
n = 0
M = None
WHITE = 0
GRAY = 1
BLACK = 2
INF = float('inf')
d = None


def main():
    global n, M, d
    M = [[0 for _ in range(N)] for _ in range(N)]
    n = int(input())
    d = [INF for _ in range(n)]

    for _ in range(n):
        u, k, *v_s = map(int, input().split(' '))
        for j in range(k):
            M[u-1][v_s[j-1]-1] = 1

    bfs()

    for i in range(n):
        print('{} {}'.format(i+1, d[i] if d[i] != INF else -1))


def bfs():
    q = deque()
    q.appendleft(0)
    d[0] = 0

    while len(q) > 0:
        u = q.pop()
        for v in range(n):
            if M[u][v] == WHITE:
                continue
            if d[v] != INF:
                continue
            d[v] = GRAY
            d[v] = d[u] + 1
            q.appendleft(v)


if __name__ == '__main__':
    main()

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

import sys
import os
import math

N = int(input())

E = []
E.append([])
d = [None] * (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 collections
n= int(input())
g=[]
for _ in range(n):
    v,k,*varray= map(int,input().split())
    g.append(varray)
        

d= [-1]* (n+10)
d[0]=0
q= collections.deque()
q.append(0)
while len(q)>  0:
    cur = q.popleft()
    for next in g[cur]:
        if d[next-1]== -1:
            d[next-1]= d[cur]+1
            q.append(next-1)
            
for i in range(n):
    print(i+1,d[i])

Python: n=int(input())
d=[0]+[float('inf')]*(n-1)

v=[[]]*n
for i in range(n):
    tmp=list(map(int,input().split()))
    tmp=[i-1 for i in tmp[2:]]
    v[i]=tmp

que=[0]
while que!=[]:
    m=que.pop(0)
    for i in v[m]:
        if d[i]==float('inf'):
            que.append(i)
            d[i]=d[m]+1
for i in range(n):
    if d[i]==float('inf'):
        d[i]=-1
    print(i+1,d[i])

Python: from collections import deque


def bfs(g, source):
    n = len(g)
    d = [float('inf') for _ in range(n)]
    d[0] = 0
    queue = deque()
    queue.append(0)
    while len(queue) > 0:
        cur = queue.popleft()
        for next in g[cur]:
            if d[cur] + 1 < d[next]:
                d[next] = d[cur] + 1
                queue.append(next)
    return d


def main():
    n = int(input())
    g = [[] for _ in range(n)]
    for _ in range(n):
        inp = list(map(int, input().split()))
        m = inp[0] - 1
        k = inp[1]
        for i in range(k):
            g[m].append(inp[i+2] - 1)
    d = bfs(g, 0)
    for i in range(n):
        if d[i] == float('inf'):
            d[i] = -1
        print(i+1, d[i])


if __name__ == '__main__':
    main()

Python: import sys
sys.setrecursionlimit(10000000)
MOD = 10 ** 9 + 7
INF = 10 ** 15

from collections import deque,defaultdict,Counter
def main():
    N = int(input())
    G = [[] for _ in range(N)]
    for i in range(N):
        A = list(map(int,input().split()))
        for a in A[2:]:
            a -= 1
            G[i].append(a)
    
    q = deque([0])
    dist = [-1] * N
    dist[0] = 0
    while q:
        v = q.popleft()
        for e in G[v]:
            if dist[e] >= 0:
                continue
            dist[e] = dist[v] + 1
            q.append(e)
    
    ans = [(i + 1,dist[i]) for i in range(N)]
    for t in ans:
        print(*t)
if __name__ == '__main__':
    main()

Python: from collections import deque
n=int(input())
E=[0]*n
for _ in range(n):
    u,k,*V=map(int,input().split())
    E[u-1]=V
d=[-1]*n
d[0]=0
todo=deque([1])
while todo:
    now=todo.popleft()
    for v in E[now-1]:
        if d[v-1]==-1:
            todo.append(v)
            d[v-1]=d[now-1]+1
for i in range(n):
    print(i+1,d[i])

Python: from sys import stdin
from collections import deque

n = int(stdin.readline())
g = [None] * n
for _ in range(n):
    u, _, *cs = [int(s) for s in stdin.readline().split()]
    g[u-1] = [c - 1 for c in cs]
ds = [-1] * n
v = [False] * n
v[0] = True
q = deque([(0, 0)])
while len(q):
    u, d = q.popleft()
    ds[u] = d
    for c in g[u]:
        if not v[c]:
            v[c] = True
            q.append((c, d + 1))
for u, d in enumerate(ds):
    print(u + 1, d)