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: # -*- coding: utf_8 -*-

level = True
def debug(v):
    if level:
        print(v)

NOT_FOUND = 0
ENQUEUED = 1
FOUND = 2

def bfs(graph, status, results):
    queue = []
    queue.append(1)
    while len(queue) != 0:
        node = queue.pop(0)
        status[node] = FOUND
        d = results[node]
        for edge in graph[node]:
            if status[edge] != NOT_FOUND:
                continue
            status[edge] = ENQUEUED
            queue.append(edge)
            results[edge] = d + 1

    return results

if __name__ == "__main__":
    n = int(input())
    status = [NOT_FOUND] * (n + 1)
    results = [0] * (n + 1)
    g = [[0]]

    for i in range(n):
        row = [int(x) for x in input().split()]
        row.pop(0)
        row.pop(0)
        g.append(row)

    bfs(g, status, results)
    results.pop(0)

    print(results)
    for idx, v in enumerate(results):
        print(idx + 1, v)

Python: n = int(input())

m = [[0 for _ in range(n+1)] for _ in range(n+1)]
mm = [[] for _ in range(n+1)]

for _ in range(n):
	tmp = [int(x) for x in input().split()]
	u,k,l = tmp[0],tmp[1],tmp[2:]
	mm[u] += tmp[2:]
	for x in l:
		m[u][x] = 1
		
dp = [float('inf') for _ in range(n+1)]
queue = [1]

while queue:
	t = queue.pop(0)
	for x in mm[t]:
		if dp[x] > dp[t] + 1:
			dp[x] = dp[t] + 1
			queue.append(x)
		else:
			pass
			
for i,x in enumerate(queue):
	if i == 0:
		pass
	else:
		if x == float('inf'):
			print(i, -1)
		else:
			print(i, x)

Python: import collections

N = int(input())
M = []
for i in range(N):
    a = list(map(int,input().strip().split()))
    b = [int(i+1 in a[2:]) for i in range(N)]
    M.append(b)

D = [-1 for _ in range(N)]
D[0] = 0 # 始点への距離は 0, 他の距離は-1
Q = collections.deque()
Q.append(0) # 始点
while len(Q) > 0:
    #print("bfs", Q) # 各ステップでの Q の動作を確認
    cur = Q.popleft()
    for dst in range(N):
        # curからdstに移動可能かつ、dstが未訪問だったら
        if M[cur][dst] == 1 and D[dst] == -1:
            D[dst] = D[cur]+1
            Q.append(dst) # Qにdstを詰める
for v in range(N):
    print(v+1, D[v])

Python: import heapq
from collections import deque
from enum import Enum
import sys
import math
from _heapq import heappush, heappop

BIG_NUM = 2000000000
MOD = 1000000007
EPS = 0.000000001

class Info:
    def __init__(self,arg_node_id,arg_sum_cost):
        self.node_id = arg_node_id
        self.sum_cost = arg_sum_cost


V = int(input())
ADJ = [[] for i in range(V)]

for loop in range(V):
    input_str = list(map(int,input().split()))
    node_id = input_str[0]-1
    for i in range(input_str[1]):
        ADJ[node_id].append(input_str[2+i]-1)

visited = [False]*V
visited[0] = True

min_dist = [-1]*V
min_dist[0] = 0

Q = deque()
Q.append((Info(0,0)))

while len(Q) > 0:
    info = Q.popleft()
    for next_node in ADJ[info.node_id]:
        if visited[next_node] == True:
            continue
        visited[next_node] = True
        min_dist[next_node] = info.sum_cost+1
        Q.append((Info(next_node,min_dist[next_node])))

for i in range(V):
    print("%d %d"%(i+1,min_dist[i]))

Python: from collections import deque
V = int(input())
edge = [[] for _ in range(V)]
for _ in range(V):
    u, _, *v = map(lambda x: int(x)-1, input().split())
    edge[u] = v
dist = [-1] * V
dist[0] = 0
que = deque([0])

while len(que):
    v = que.popleft()
    for c in edge[v]:
        if dist[c] == -1:
            dist[c] = dist[v] + 1
            que.append(c)
for i, d in enumerate(dist):
    print(i+1, d)

Python: n = int(input())
a = [[] for i in range(n)]

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

d = [0] * n
isDiscovered = [False] * n

def bfs(x):
    global time_stamp
    isDiscovered [x] = True
    time_stamp += 1
    for i in a[x]:
        if not isDiscovered[i]:
            d[i] = d[x] + 1

bfs(0)
d_ = 1
while not(isDiscovered == [True] * n):
    for i in range(n):
        if d[i] is d_ and not isDiscovered[i]:
            bfs(i)
    d_ += 1

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

Python: from collections import deque

n = int(input())
graph = [[0]]
for _ in range(n):
    u, k, *v = map(int, input().split())
    graph.append(v)

queue = deque([1])
ans = [-1 for _ in range(n + 1)]
ans[1] = 0
while queue:
    cur = queue.popleft()
    for next in graph[cur]:
        if ans[next] != -1:
            continue
        ans[next] = ans[cur] + 1
        queue.append(next)
for i in range(1, n + 1):
    print(i, ans[i])

Python: class Queue:
  def __init__(self,c):
    self.values = [None]*(c+1)
    self.s = 0
    self.t = 0

  def push(self,x):
    if self._next(self.s) == self.t:
      raise Exception("Overflow")
    self.values[self.s] = x
    self.s = self._next(self.s)

  def pop(self):
    if self.s == self.t:
      raise Exception("Underflow")
    ret = self.values[self.t]
    self.t = self._next(self.t)
    return ret

  def size(self):
    if self.s >= self.t:
      return self.s-self.t
    else:
      return len(self.values) - (self.t-self.s)


  def _next(self,p):
    p += 1
    if p >= len(self.values):
      p = 0
    return p


def solve(G):
  d = {}
  n = len(G)
  for u in G:
    d[u] = -1
  d[1] = 0
  queue = Queue(n+1)
  queue.push(1)
  while queue.size() > 0:
    u = queue.pop()
    for v in G[u]:
      if d[v] == -1:
        d[v] = d[u] + 1
        queue.push(v)
  return d







n = int(input())
G = {}
for i in range(n):
  entry = list(map(int, input().split(' ')))
  u = entry[0]
  k = entry[1]
  G[u] = set()
  for v in entry[2:]:
    G[u].add(v)


d = solve(G)
for u in G:
  print(u,d[u])

Python: from collections import deque
n=int(input())
d=[-1]*(n+1)
d[1]=0
v=[[] for i in range(n+1)]
for i in range(n):
  a=list(map(int,input().split()))
  v[a[0]]=a[2:]
q=deque()
q.append(1)
while len(q)>0:
  curr=q.popleft()
  for i in v[curr]:
    if d[i]==-1:
      d[i]=d[curr]+1
      q.append(i)
for i in range(1,n+1):
  print(f'{i} {d[i]}')

Python: #!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin
from Queue import Queue
 
 
def main():
    num = int(stdin.readline())
 
    L = []
    for _ in xrange(num):
        L.append([int(s) for s in stdin.readline().split()[2:]])
 
    d = [-1] * num
    d[0] = 0
    q = Queue(100)
    q.put(0)
    while not q.empty():
        u = q.get()
        for v in L[u]:
            if d[v-1] < 0:
                d[v-1] = d[u] + 1
                q.put(v-1)
 
    for i, v in enumerate(d):
        print(i+1, v)
 
 
main()