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: # -*- coding: utf-8 -*-
import sys
from collections import deque
sys.setrecursionlimit(10**9)
INF=10**18
MOD=10**9+7
input=lambda: sys.stdin.readline().rstrip()
YesNo=lambda b: print('Yes' if b else 'No')
YESNO=lambda b: print('YES' if b else 'NO')

def main():
    N=int(input())
    edge=[[] for _ in range(N)]
    for i in range(N):
        l=list(map(lambda x:int(x)-1,input().split()))
        edge[i]=l[2:]
    d=[INF]*N
    d[0]=0
    que=deque()
    que.append(0)
    while que:
        v=que.popleft()
        for nv in edge[v]:
            if d[nv]>d[v]+1:
                d[nv]=d[v]+1
                que.append(nv)
    for i in range(N):
        print(i+1,d[i] if d[i]!=INF else -1)

if __name__ == '__main__':
    main()

Python: def bfs(adj, s):
    n = len(adj)
    d = [-1 for _ in range(n)]
    c = [0 for _ in range(n)]

    d[s] = 0
    c[s] = 1

    queue = [s]

    while len(queue) > 0:
        u = queue.pop()
        for v in adj[u]:
            if c[v] == 0:
                c[v] = 1
                d[v] = d[u] + 1
                queue.append(v)

    return d


n = int(input())
adj = [[] for _ in range(n)]
for _ in range(n):
    s = [int(x) for x in input().split()]
    u = s[0]
    for v in s[2:]:
        adj[u - 1].append(v - 1)

d = bfs(adj, 0)

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

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

while Q:top = Q[0];func(top);del Q[0]

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

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

"""
input:
4
1 2 2 4
2 1 4
3 0
4 1 3

output:
1 0
2 1
3 2
4 1
"""

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_index, adj_num, *adj_list = map(int, v_detail)
        # assert len(adj_list) == adj_num
        init_adj_table[v_index].extend(adj_list)
    return init_adj_table


def graph_bfs(v_init):
    status[v_init] = VISITED_IN_QUEUE
    distance[v_init] = 0
    queue.appendleft(v_init)

    while queue:
        current = queue.popleft()
        for v in adj_table[current]:
            if status[v] is UNVISITED:
                status[v] = VISITED_IN_QUEUE
                distance[v] = distance[current] + 1
                queue.append(v)
        status[current] = POPPED_OUT
    return distance


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

    # config length = (vertex_num + 1)
    queue = deque()
    status = [UNVISITED] * (vertices_num + 1)
    distance = [-1] * (vertices_num + 1)

    adj_table = generate_adj_matrix(vertices_info)
    ans = graph_bfs(1)
    for k, v in enumerate(ans[1:], 1):
        print(k, v)

Python: from sys import stdin
from collections import deque

def read_graph(n):
    A = [ [0]*(n+1) for _ in range(n+1) ]
    for _ in range(n):
        line = deque(stdin.readline().strip().split())
        i = line.popleft()
        line.popleft()
        for k in line:
            A[int(i)][int(k)] = 1
    return A

def bfs_ctrl(n, A):
    color = ["WHITE"] * (n+1)
    d = [-1] * (n+1)
    Q = deque([])

    def bfs(s):
        nonlocal color
        nonlocal d
        nonlocal Q
        color[s] = "GRAY"
        d[s] = 0
        Q.append(s)

        while Q:
            u = Q.popleft()
            for v in range(1, n+1):
                if A[u][v] and color[v] == "WHITE":
                    color[v] = "GRAY"
                    d[v] = d[u] + 1
                    Q.append(v)

            color[u] = "BLACK"

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

n = int(input())
A = read_graph(n)
bfs_ctrl(n, A)

Python: from collections import deque
INF = 1145141919810364364334
s = [None]
r = [None]

n = int(input())
for _ in range(n):
    temp = list(map(int,input().split()))
    s.append(temp[2:])
    
d = [INF] * (n+1)

d[1] = 0
q = deque()
q.append(1)

while q:
    x = q.popleft()
    for i in s[x]:
        if d[i] == INF:
            q.append(i)
            
        d[i] = min(d[x] + 1 , d[i])
        
for i in range(1,n+1):
    if d[i] == INF:
        d[i] = -1
    print(i,d[i])

Python: def main():
    import sys
    N = int(sys.stdin.readline())
    L1 = [list(map(int, sys.stdin.readline().split())) for i in range(N)]
    L = [[] for _ in range(N+1)]
    for row in L1:
        L[row[0]] += row[2:]
    #print(L)
    
    d = [-1 for i in range(N+1)] #距離
    def bfs(p, queue=[]):
        queue+=[p]
        d[p]=0
        while queue:
            now = queue.pop(0)
            for ch in L[now]:
                if d[ch] ==-1: #未開
                    d[ch] = d[now]+1
                    queue +=[ch]
    
    
    bfs(1)
    for idx, ans in enumerate(d[1:]):
        print(idx+1, ans)


if __name__=='__main__':
    main()

Python: from collections import deque


def bfs(root):
    Q = deque()
    distance[root] = 0
    Q.append(root)
    i = root
    while len(Q) > 0:
        i = Q.popleft()
        for v in range(n):
            if adjMat[i][v] == 1 and color[v] == 'white':
                Q.append(v)
                color[v] = 'gray'
                distance[v] = distance[i] + 1
        color[i] = 'black'


n = int(input())
adjMat = [[0] * n for _ in range(n)]
color = ['white'] * n
distance = [-1] * n

for _ in range(n):
    adj = list(map(int, input().split()))
    i = adj[0]
    v = adj[2:]
    for j in v:
        adjMat[i - 1][j - 1] = 1

bfs(0)

for i in range(n):
    out = ''
    out += '{} {}'.format(i + 1, distance[i])
    print(out)