Go: package main

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

type AdjacentList struct {
	matrix [][]int
}

func NewEmptyAdjacentList(dim int) *AdjacentList {
	matrix := make([][]int, dim)
	for i := 0; i < dim; i++ {
		matrix[i] = make([]int, dim)
	}
	return &AdjacentList{matrix: matrix}
}

func (al *AdjacentList) set(node int, adjacent int) {
	al.matrix[node-1][adjacent-1] = 1
}

func (al *AdjacentList) findAdjacentsFor(node int) []int {
	adjacents := []int{}
	for i, v := range al.matrix[node-1] {
		if v == 1 {
			adjacents = append(adjacents, i+1)
		}
	}
	return adjacents
}

type DistanceList struct {
	list []int
}

func NewDistanceList(dim int) *DistanceList {
	list := make([]int, dim)
	for i := 0; i < dim; i++ {
		list[i] = -1
	}
	return &DistanceList{list: list}
}

func (dl *DistanceList) set(node int, distance int) {
	dl.list[node-1] = distance
}

func (dl *DistanceList) get(node int) int {
	return dl.list[node-1]
}

func (dl *DistanceList) isVisited(node int) bool {
	return dl.list[node-1] >= 0
}

type Position struct {
	node     int
	distance int
}

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

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

	al := NewEmptyAdjacentList(dim)

	for i := 1; i <= dim; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}

		adjacentNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		for j := 0; j < adjacentNum; j++ {
			adjacent, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			al.set(node, adjacent)
		}
	}

	dl := NewDistanceList(dim)

	bfs(al, dl)

	for i := 1; i <= dim; i++ {
		fmt.Printf("%d %d\n", i, dl.get(i))
	}
}

func bfs(al *AdjacentList, dl *DistanceList) {
	stack := []Position{Position{node: 1, distance: 0}}
	for len(stack) > 0 {
		currentPosition := stack[0]
		stack = stack[1:]
		if !dl.isVisited(currentPosition.node) {
			dl.set(currentPosition.node, currentPosition.distance)
		}
		for _, v := range al.findAdjacentsFor(currentPosition.node) {
			stack = append(stack, Position{node: v, distance: currentPosition.distance + 1})
		}
	}
}

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

Python: N = int(input())
L = [[] for i in range(N+1)]
d = [-1] * (N+1)
f = [0] * (N+1)
nkey = []
ntime = []


def bfs():
    while len(nkey):
        key = nkey.pop(0)
        time = ntime.pop(0)
        if d[key] == -1:
            d[key] = time
        for i in range(len(L[key])):
            if d[L[key][i]] == -1:
                nkey.append(L[key][i])
                ntime.append(time+1)
        

for i in range(N):
    Q = list(map(int, input().split()))
    L[Q[0]].extend(Q[2:])

nkey.append(1)
ntime.append(0)
bfs()


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

Python: n=int(input())
a=[]
from collections import deque as dq
for i in range(n):
	aaa=list(map(int,input().split()))
	aa=aaa[2:]
	a.append(aa)
dis=[-1]*n
dis[0]=0
queue=dq([0])
while queue:
	p=queue.popleft()
	for i in range(len(a[p])):
		if dis[a[p][i]-1]==-1:
			queue.append(a[p][i]-1)
			dis[a[p][i]-1]=dis[p]+1
for i in range(n):
	print(i+1,dis[i])

Python: n = int(input())
adjlis = []
for _ in range(n):
    lis=list(map(int,input().split()))
    adjlis.append(lis[2:])

visited = [False]*n
dislis = [n+1]*n
Q = [[1,0]]

def pull():
    return Q.pop(0)

def push(x):
    Q.append(x)

while len(Q)>0:
    cur = pull()
    curpoint = cur[0]
    count = cur[1]
    if not visited[curpoint-1]:
        visited[curpoint-1]=True
        dislis[curpoint-1] = count
        for i in adjlis[curpoint-1]:
            push([i,count+1])


for i in range(n):
    if dislis[i]==n+1:
        dislis[i] = -1
    print(i+1,dislis[i])

Python: n = int(input())
graph = [[0 for i in range(n)] for j in range(n)]
d = [0] * n
f = [0] * n
queue = [0]


for i in range(n):
   a = list(map(int, input().split()))
   for j in range(0, a[1], 1):
       graph[a[0] - 1][a[2 + j] - 1] = 1

f[0] = 1
while len(queue) != 0:
    i = queue.pop(0)
    for j in range(n):
        if (graph[i][j] == 1) & (f[j] == 0):
            queue.append(j)
            f[j] = 1
            d[j] = d[i] + 1

[print(i+1, d[i] if (i == 0) | (d[i] != 0) else -1) for i in range(n)]

Python: import sys
from collections import defaultdict
from queue import Queue


def main():
    input = sys.stdin.buffer.readline
    n = int(input())
    g = defaultdict(list)
    for i in range(n):
        line = list(map(int, input().split()))
        if line[1] > 0:
            g[line[0]] = line[2:]
    q = Queue()
    q.put(1)
    dist = [-1] * (n + 1)
    dist[1] = 0
    while not q.empty():
        p = q.get()
        for nxt in g[p]:
            if dist[nxt] == -1:
                dist[nxt] = dist[p] + 1
                q.put(nxt)
    for i in range(1, n + 1):
        print(i, dist[i])


if __name__ == "__main__":
    main()

Python: from collections import deque
from enum import Enum, auto

class Color(Enum):
    WHITE = auto()
    GRAY = auto()
    BLACK = auto()

n = int(input())
d = [0 for i in range(n)]
f = [0 for i in range(n)]

colors = [] # 頂点の訪問状態
A = [[0 for j in range(n)] for i in range(n)] # 隣接行列
queue = deque([])

# 隣接行列の初期化
for i in range(n):
    arr = list(map(int, input().split(' ')))
    u, k, v = arr[0], arr[1], arr[2:]
    for j in range(k):
        A[u-1][v[j]-1] = 1

def bfs():
    global colors, queue, d
    colors = [Color.WHITE for i in range(n)]
    d = [-1 for i in range(n)] # INF

    colors[0] = Color.GRAY
    d[0] = 0
    queue.append(0)

    while len(queue) > 0:
        u = queue.pop()
        for v in range(n):
            if A[u][v] == 1 and colors[v] == Color.WHITE:
                colors[v] == Color.GRAY
                d[v] = d[u] + 1
                queue.append(v)
        colors[u] = Color.BLACK

bfs()

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

Python: import sys, math
from itertools import permutations, combinations
from collections import defaultdict, Counter, deque
from math import factorial#, gcd
from bisect import bisect_left #bisect_left(list, value)
sys.setrecursionlimit(10**7)
enu = enumerate
MOD = 10**9+7
def input(): return sys.stdin.readline()[:-1]
def pri(x): print('\n'.join(map(str, x)))

N = int(input())
ukv = [list(map(int, input().split())) for _ in range(N)]
dist = [-1]*N
dist[0] = 0

deq = deque()
#deq.append(ukv[0][2:])
deq.append([1])

step = 0
while deq[0]:
#    print('deq:', deq)
    nextvs = []
    currvs = deq.popleft()
    for v in currvs:
        for nv in ukv[v-1][2:]:
            if dist[nv-1] == -1:
                dist[nv-1] = step+1
                nextvs.append(nv)
    deq.append(nextvs)
    step += 1

res = [[val1, val2] for val1, val2 in zip(range(1, N+1), dist)]
for a in res:
    print(*a)

Python: #coding:utf-8
n = int(input())
Q = [1]
M = [[False for i in range(n)] for j in range(n)]
dataList = []
for i in range(n):
    data = list(map(int,input().split()))
    dataList.append(data)
    for j in range(data[1]):
        v = data[j+2] - 1
        M[i][v] = True
color = ["white" for i in range(n)]
d = [-1 for i in range(n)]
d[0] = 0
while Q != []:
    u = Q.pop(0) - 1
    color[u] = "gray"
    data = dataList[u]
    for i in range(data[1]):
        v = data[i+2] - 1
        if M[u][v] == True and color[v] == "white":
            d[v] = d[u] + 1
            Q.append(v+1)
    color[u] = "black"

for i,j in enumerate(d,1):
    print(i,j)