Go: package main

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

var distance []int

type queue struct {
	q    []int
	head int
	tail int
}

func (q *queue) push(n int) {
	q.q[q.tail] = n
	q.tail++
}

func (q *queue) pop() int {
	q.head++
	return q.q[q.head-1]
}

func (q *queue) isEmpty() bool {
	return q.head == q.tail
}

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func bfs(graph [][]int, s int) {
	distance = make([]int, len(graph))

	infty := -1
	for i := 0; i < len(distance); i++ {
		distance[i] = infty
	}
	distance[s] = 0

	q := &queue{make([]int, 1000), 0, 0}
	q.push(s)

	for !q.isEmpty() {
		u := q.pop()
		for i := 0; i < len(graph); i++ {
			if graph[u][i] == 0 {
				continue // u, i間に辺がない場合
			}
			if distance[i] != infty {
				continue // 訪問済みの場合
			}
			// 訪問するnodeの始点からの距離を設定し、訪問キューに入れる
			distance[i] = distance[u] + 1
			q.push(i)
		}
	}

	// print distance
	for i, d := range distance {
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	adj := makeAdjList()
	bfs(adj, 0)
}

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
from collections import deque

UNVISITED, VISITED_IN_QUEUE, POPPED_OUT = 0, 1, 2


def generate_adj_matrix(v_info):
    for v_detail in v_info:
        v_adj_list = v_detail[2:]
        # assert len(v_adj_list) == int(v_detail[1])
        for each in v_adj_list:
            init_adj_matrix[int(v_detail[0]) - 1][int(each) - 1] = 1
    return init_adj_matrix


def graph_bfs(v_init):
    vertices_status_list[v_init] = VISITED_IN_QUEUE
    vertices_distance_list[v_init] = 0
    vertices_visit_queue.appendleft(v_init)

    while vertices_visit_queue:
        current_vertex = vertices_visit_queue.popleft()
        for v in range(1, vertices_num + 1):
            if adj_matrix[current_vertex - 1][v - 1] and vertices_status_list[v] is UNVISITED:
                vertices_status_list[v] = VISITED_IN_QUEUE
                vertices_distance_list[v] = vertices_distance_list[current_vertex] + 1
                vertices_visit_queue.appendleft(v)
        vertices_status_list[current_vertex] = POPPED_OUT
    return vertices_distance_list


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertices_num = int(_input[0])
    vertices_info = list(map(lambda x: x.split(), _input[1:]))
    init_adj_matrix = [[0] * vertices_num for _ in range(vertices_num)]
    # assert len(vertex_info) == vertex_num

    # config length = (vertex_num + 1)
    vertices_visit_queue = deque()
    vertices_status_list = [UNVISITED] * vertices_num
    vertices_status_list.insert(0, -1)
    vertices_distance_list = [0] * (vertices_num + 1)

    adj_matrix = generate_adj_matrix(vertices_info)
    ans = graph_bfs(v_init=1)
    for j in range(vertices_num):
        print(j + 1, ans[j + 1])

Python: N = int(input())
edge = [[] for _ in range(N)]

for _ in range(N):
    l = list(map(int, input().split()))
    for j in range(l[1]):
        edge[l[0]-1].append(l[2+j]-1)


now_list = [0]
next_list = []
dist = 0
dists = [-1] * N
while len(now_list) > 0:
    for _ in range(len(now_list)):
        v = now_list.pop()
        if dists[v] == -1:
            dists[v] = dist
        else:
            continue
        for nv in edge[v]:
            next_list.append(nv)
    now_list = next_list
    next_list = []
    dist += 1

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

Python: from collections import deque
import sys

INFTY=sys.maxsize
WHITE=0
GRAY=1
BLACK=2

color=[]
d=[]
Q=deque([])
n=0
L=[]

def readinput():
    global n
    global L

    n=int(input())
    for i in range(n+1):
        L.append([])

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


def bfs(s):
    global color
    global d
    global Q

    for i in range(n+1):
        color=[WHITE]*(n+1)
        d=[-1]*(n+1)

    color[s]=GRAY
    d[s]=0
    Q.append(s)

    while(len(Q)>0):
        u = Q.popleft()
        for l in L[u]:
            if(color[l]==WHITE):
                color[l]=GRAY
                d[l]=d[u]+1
                Q.append(l)
        color[u]=BLACK

if __name__=='__main__':
    readinput()
    bfs(1)
    for i in range(1,n+1):
        print('{} {}'.format(i, d[i]))

Python: import numpy as np
N= int(input())
frag, T, L, Q = np.zeros(N),np.zeros(N),np.zeros(N),[0]
# frag, T, L,Q = [0]*N, [0]*N, [0]*N, [0]
a = 100
frag[0] = 1
def func(ide):
#     print("frag = {}".format(frag))
    for i in E[ide]:
        i = int(i) - 1
        if frag[i] != 1:
            frag[i] = 1
            L[i] = L[ide] +1 
            Q.append(i) 
        else:
            return None
            


E = [input().split()[2:] for _ in range(N)]

while Q:
    top = Q[0]
    func(top)
    del Q[0]
for i in range(N):print(i + 1 ,int(L[i]))

Python: N = int(input())
G = [None for i in range(N)]
for i in range(N):
    u, k, *vs = map(int, input().split())
    G[u-1] = [e-1 for e in vs]


from collections import deque
dist = [-1]*N
que = deque([0])
dist[0] = 0
while que:
    v = que.popleft()
    d = dist[v]
    for w in G[v]:
        if dist[w] > -1:
            continue
        dist[w] = d + 1
        que.append(w)

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