Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

Python: import sys
from collections import deque

n = int(sys.stdin.readline().strip())
edges = [[] for _ in range(n)]
for _ in range(n):
    tmp = list(map(int, sys.stdin.readline().strip().split(" ")))
    for node in tmp[2:]:
        edges[tmp[0] - 1].append(node-1)
# print(edges)

distance = [0] * n
q = deque()
q.append((0, 0))
visited = set()
while q:
    node, d = q.popleft()
    # print(node, d)
    if node in visited:
        continue
    distance[node] = d
    visited.add(node)
    for next in edges[node]:
        # print("next", next)
        q.append((next, d + 1))

for i, d in enumerate(distance):
    if i == 0:
        print(1, 0)
    else:
        print(i + 1, d if d > 0 else -1)

Python: import collections

def breadth_first_search(g,check,length):
    q = collections.deque()
    q.append(1)
    check[1] = 1
    length[1] = 0
    while len(q) != 0:
        v = q.popleft()
        for u in g[v]:
            if check[u] == 0:
                check[u] = 1
                length[u] = length[v]+1
                q.append(u)

    return length

def main():
    N = int(input())
    g = []
    g.append([])
    for i in range(N):
        tmp = input().split()
        tmp_ls = []
        for i in range(int(tmp[1])):
            tmp_ls.append(int(tmp[i+2]))
        g.append(tmp_ls)

    check = [0]*(N+1)
    length = [0]*(N+1)
    ans = breadth_first_search(g,check,length)
    for i in range(N):
        node_num = i+1
        if ans[node_num] == 0 and i != 0:
            ans[node_num] = -1
        print(node_num,ans[node_num])

main()

Python: from collections import deque

def main():
    n = int(input())
    V = [None]*(n+1)
    ans = [None]*(n+1)
    for i in range(1, n+1):
        _, _, *v = map(int, input().split())
        V[i] = v
    q = deque([1])
    ans[1] = 0
    while q:
        node = q.pop()
        d = ans[node]+1
        for v in V[node]:
            if ans[v] is None:
                ans[v] = d
                q.appendleft(v)
    print(1, 0)
    for i, distance in enumerate(ans[2:], 2):
        print(i, distance or -1)

if __name__ == "__main__":
    main()

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


while Q:top = Q.pop(0);func(top)

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

Python: from collections import deque
n=int(input())
l=[list(map(int,input().split())) for i in range(n)]
d=deque()
d.append(1)
check=[0]*n
check[0]=1
ans=[0]*n
kyori=[0]*n
while len(d)!=0:
  v=d.popleft()
  for i in l[v-1][2:]:
    if check[i-1]==0:
      check[i-1]=1
      ans[i-1]=(kyori[v-1]+1)
      kyori[i-1]=(kyori[v-1]+1)
      d.append(i)
for i in range(1,n):
  if ans[i]==0:
    ans[i]=-1
for i in range(n):
    print(i+1,ans[i])

Python: # coding: utf-8

from queue import Queue

N = int(input())
graph = [None]
for _ in range(N):
    graph.append(list(map(int, input().split(" ")))[1:])

class BFSSolver:

    def __init__(self, graph):
        self.graph = graph
        self.queue = Queue()
        self.queue.put(1)
        self.before_id = 1
        self.already_searched = [1]
        self.res = [0]
        for _ in range(N):
            self.res.append(-1)
        self.res[1] = 0
        self.turn = 0

    def next_turn(self):
        now_id = self.queue.get()
        before_id = now_id
        neighbors = self.graph[now_id][1:]
        for i in neighbors:
            if i not in self.already_searched:
                self.turn = self.res[before_id] + 1
                self.already_searched.append(i)
                self.res[i] = self.turn
                self.queue.put(i)

    def solve(self):
        while not self.queue.empty():
            self.next_turn()

        for id, i in enumerate(self.res[1:]):
            print("{} {}".format(id+1, i))

s = BFSSolver(graph)
s.solve()

Python: #!/usr/bin/python3

def find(id, V, d, dist):
    i = id - 1
    dist[i] = d
    for v in V[i]:
        find(v, V, d + 1, dist)
    
n = int(input())
# [isFind, d, f]
A = [[False, 0, 0] for i in range(n)]
U = []
V = []
dist = [-1] * n
for i in range(n):
    l = list(map(int, input().split()))
    U.append(l[0])
    V.append(l[2:])

find(1, V, 0, dist)

for u in U:
    print(u, dist[u - 1])

Python: import collections

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

dist = [-1]*N
que = collections.deque()

G = [[]]*N
for ukv in UKV:
    G[ukv[0]-1] = sorted(ukv[2:])

dist[0] = 0
que.append(1)

while len(que) != 0:
    v = que.popleft()
    for nv in G[v-1]:
        if dist[nv-1] != -1:
            continue
        dist[nv-1] = dist[v-1] + 1
        que.append(nv)

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

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

def BFS(adj, start):
    n = len(adj)
    d = [n] * n
    flag = [0] * n
    Q = []

    Q.append(start)
    d[start] = 0

    while len(Q) != 0:
        u = Q.pop(0)
        v = [i for i, x in enumerate(adj[u]) if (x == 1) and (flag[i] == 0)] # v <= ??£??\???????????????????????¢?´¢??????????????????
        
        for i in v:
            Q.append(i)
            d[i] = min(d[u] + 1, d[i])
            flag[u] = 1
    
    for i in range(n):
        if d[i] == n:
            d[i] = -1

    return d

def main():
    n = int(input())
    adj = [[0 for i in range(n)] for j in range(n)]
    
    for i in range(n):
        tmp = list(map(int, input().split()))
        u = tmp[0]
        u = u -1
        k = tmp[1]
        v = tmp[2:]
        for j in range(k):
            adj[u][v[j]-1] = 1
    
    d = BFS(adj, 0)
    for i in range(n):
        print(i+1, d[i])


if __name__ == "__main__":
    main()

Python: from collections import deque
u = int(input())
g = [[i for i in map(int, input().split())] for _ in range(u)]
graph = [[] for _ in range(u)]
ans = [-1] * u
for i in range(u):
    for j in range(g[i][1]):
        graph[i].append(g[i][2 + j] - 1)
que = deque()
que.append(0)
ans[0] = 0
while que:
    v = que.popleft()
    for nv in graph[v]:
        if ans[nv] != -1:
            continue
        ans[nv] = ans[v] + 1
        que.append(nv)

for i in range(u):
    print(i+1, ans[i])