Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

Python: ii = lambda : int(input())
li = lambda : list(map(int,input().split()))

from collections import deque

class tree:
    def __init__(self,n):
        self.n = n
        self.arr = [[] for i in range(self.n)]
        self.root = [-1]*n

    def add_arr(self, u, v):
        if v[0] != 0:
            self.arr[u-1] = v[1:]

n = ii()
t = tree(n)
for i in range(n):
    uk = li()
    t.add_arr(uk[0],uk[1:])
l = deque()
l.append(0)
t.root[0] = 0
while len(l)>0:
    p = l.popleft()
    for i in t.arr[p]:
        if t.root[i-1] == -1:
            t.root[i-1] = t.root[p]+1
            l.append(i-1)

for k,i in enumerate(t.root):
    print(k+1,i)

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)]
dp[1] = 0
queue = [1]

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

Python: import sys

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG:{} -> {}'.format(name, val), file=sys.stderr)
            return None

def bfs(adj, nxt, dis, sumi, kyori):
    nnxt = []
    for u in nxt:
        sumi[u] = True
        dis[u] = kyori

    for u in nxt:
        for v in adj[u]:
            if not sumi[v]:
                nnxt.append(v)

    return nnxt, kyori + 1

def solve():
    n = int(input())
    adj = [None] * n
    for i in range(n):
        u, k, *vs = [int(j) - 1 for j in input().split()]
        adj[u] = vs

    # debug(adj, locals())

    sumi = [False] * n
    dis = [-1] * n
    nxt = [0]
    kyori = 0

    while nxt:
        nxt, kyori = bfs(adj, nxt, dis, sumi, kyori)

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

    pass

if __name__ == '__main__':
    solve()

Python: from collections import deque
n = int(input())
edges = [[]] + [list(map(int, input().split())) for _ in range(n)]
inf = 10 ** 4
d = [inf for _ in range(n+1)]

que = deque()
d[1] = 0
que.append(1)
while que:
    cur = que.popleft()
    for to in edges[cur]:
        if d[to] == inf:
            d[to] = d[cur] + 1
            que.append(to)

for i in range(1, n+1):
    if d[i] == inf:
        d[i] = -1
    print(i, 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)
        else:return None
    

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

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

Python: 
def BFS(s = 0, time = 0):
    d[s] = time
    if len(Q) != 0:
        Q.pop(0)
        color[s] = 2
    for j in range(len(d)):
        if A[i][j] == 1 and color[j] == 0:
            Q.append(A[i][j])
            color[j] = 1
    for j in range(Q):
        time = time + 1
        BFS(Q[j], time)

n = int(raw_input())
A = [0] * n
for i in range(n):
    A[i] = [0] * n

for i in range(n):
    value = map(int, raw_input().split())
    u = value[0] - 1
    k = value[1]
    nodes = value[2:]
    for j in range(k):
        v = nodes[j] - 1
        A[u][v] = 1

color = [0] * n
Q = [0]
d = [-1] * n

BFS(0, 0)

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

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

d = [-1] * n

s = 1
q = []
d[s - 1] = 0
q.append(s)
while len(q):
    u = q.pop()
    v = adj[u - 1]
    for vi in v:
        if d[vi - 1] == -1:
            d[vi - 1] = d[u - 1] + 1         
            q.append(vi)
        elif d[vi - 1] > d[u - 1] + 1:
            d[vi - 1] = d[u - 1] + 1            
            q.append(vi)

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

Python: from collections import deque

N = int(input())
E = [None] * (N+1)
for _ in range(N):
    u, k, *vs = list(map(int, input().split()))
    E[u] = vs

d = [-1] * (N+1)
d[1] = 0
q = deque([(1, 0)])
while q:
    v, c = q.popleft()
    for u in E[v]:
        if d[u] < 0:
            d[u] = c+1
            q.append((u, c+1))

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

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_init():
    global colors
    colors = [Color.WHITE for i in range(n)]
    d[0] = 0
    bfs(0)

def bfs(u):
    global queue
    colors[u] = Color.GRAY

    for v in range(n):
        if A[u][v] == 1 and colors[v] == Color.WHITE and v not in queue:
            d[v] = d[u] + 1
            queue.append(v)

    while len(queue) > 0:
        v = queue.pop()
        bfs(v)

bfs_init()

for u in range(n):
    if colors[u] == Color.WHITE:
        d[u] = -1

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