Go: package main

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

type AdjacentList struct {
	matrix [][]int
}

func NewEmptyAdjacentList(dim int) *AdjacentList {
	matrix := make([][]int, dim)
	for i := 0; i < dim; i++ {
		matrix[i] = make([]int, dim)
	}
	return &AdjacentList{matrix: matrix}
}

func (al *AdjacentList) set(node int, adjacent int) {
	al.matrix[node-1][adjacent-1] = 1
}

func (al *AdjacentList) findAdjacentsFor(node int) []int {
	adjacents := []int{}
	for i, v := range al.matrix[node-1] {
		if v == 1 {
			adjacents = append(adjacents, i+1)
		}
	}
	return adjacents
}

type DistanceList struct {
	list []int
}

func NewDistanceList(dim int) *DistanceList {
	list := make([]int, dim)
	for i := 0; i < dim; i++ {
		list[i] = -1
	}
	return &DistanceList{list: list}
}

func (dl *DistanceList) set(node int, distance int) {
	dl.list[node-1] = distance
}

func (dl *DistanceList) get(node int) int {
	return dl.list[node-1]
}

func (dl *DistanceList) isVisited(node int) bool {
	return dl.list[node-1] >= 0
}

type Position struct {
	node     int
	distance int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	dim, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	al := NewEmptyAdjacentList(dim)

	for i := 1; i <= dim; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}

		adjacentNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		for j := 0; j < adjacentNum; j++ {
			adjacent, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			al.set(node, adjacent)
		}
	}

	dl := NewDistanceList(dim)

	bfs(al, dl)

	for i := 1; i <= dim; i++ {
		fmt.Printf("%d %d\n", i, dl.get(i))
	}
}

func bfs(al *AdjacentList, dl *DistanceList) {
	stack := []Position{Position{node: 1, distance: 0}}
	for len(stack) > 0 {
		currentPosition := stack[0]
		stack = stack[1:]
		if !dl.isVisited(currentPosition.node) {
			dl.set(currentPosition.node, currentPosition.distance)
		}
		for _, v := range al.findAdjacentsFor(currentPosition.node) {
			stack = append(stack, Position{node: v, distance: currentPosition.distance + 1})
		}
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

Python: from collections import deque

n = int(input())
graph = [[] for _ in range(n)]
for i in range(n):
    graph[i] += list(map(lambda x: x - 1, list(map(int, input().split()))[2:]))

visited = [-1] * n
que = deque()
# 頂点0を入れておく
que.append(0)
visited[0] = 0
cnt = 0

while que:
    v = que.popleft()
    for nv in graph[v]:
        if not visited[nv] == -1:
            continue
        visited[nv] = visited[v] + 1
        que.append(nv)

for v, d in enumerate(visited, 1):
    print(v, d)

Python: from heapq import heappush, heappop, heapify
from collections import deque, defaultdict, Counter
import itertools
from itertools import permutations, combinations, accumulate
import sys
import bisect
import string
import math
import time


def I(): return int(input())


def S(): return input()


def MI(): return map(int, input().split())


def MS(): return map(str, input().split())


def LI(): return [int(i) for i in input().split()]


def LI_(): return [int(i)-1 for i in input().split()]


def StoI(): return [ord(i)-97 for i in input()]


def ItoS(nn): return chr(nn+97)


def input(): return sys.stdin.readline().rstrip()


def show(*inp, end='\n'):
    if show_flg:
        print(*inp, end=end)


YNL = {False: 'No', True: 'Yes'}
YNU = {False: 'NO', True: 'YES'}
MOD = 10**9+7
inf = float('inf')
IINF = 10**10
l_alp = string.ascii_lowercase
u_alp = string.ascii_uppercase
ts = time.time()
sys.setrecursionlimit(10**6)
nums = ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10']

show_flg = False
# show_flg = True


def bfs(graph, initial):
    n = len(graph) - 1
    dist = [-1] * (n + 1)
    q = deque([initial])
    visited = [False] * (n + 1)
    visited[initial] = True
    dist[initial] = 0

    while len(q) != 0:
        edge = q.popleft()
        nxt = graph[edge]

        for i, e in enumerate(nxt):
            if visited[e] is False:
                q.append(e)
                dist[e] = dist[edge] + 1
                visited[e] = True

    return dist


def main():
    N = I()
    graph = [[] for i in range(N+1)]

    for i in range(N):
        a = LI()
        edge = a[0]
        if a[1] == 0:
            continue
        for e in a[2:]:
            graph[edge].append(e)
            # graph[e].append(edge)

    # print(graph)
    ret = bfs(graph, 1)
    for i in range(1, N+1):
        print(i, ret[i])


if __name__ == '__main__':
    main()

Python: import math
import copy
import sys
import fractions
# import numpy as np
# import statistics
import decimal
import heapq
import collections
import itertools
import bisect

# from operator import mul

sys.setrecursionlimit(100001)


# input = sys.stdin.readline
# sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputIntList():
    outputDataList = []
    inputData = input().split()
    outputDataList = [int(n) for n in inputData]

    return outputDataList


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

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

d = [-1] * n

for a in adj:
    for i in range(len(a)):
        a[i] -= 1

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

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

Python: n=int(input())
G=[[] for i in range(n)]
#G=[]
Q=[1]
d=[-1]*n
d[0]=0
visited=[False]*n
visited[0]=True

for i in range(n):
    arr=[int(x) for x in input().split()[2:]]
    for l in arr:
        G[i].append(l)
        #G[l-1].append(i+1)
    

kyori=0
while len(Q)!=0:
    
    #print(Q)
    #print(visited)
    v=Q.pop(0)
    
    for j in G[v-1]:
        if visited[j-1]:#次に行くところがすでに踏破済みだったら
            continue#更新しない
        else:
            d[j-1]=d[v-1]+1
            Q.append(j)
            visited[j-1]=True
for a in range(n):
    print(a+1,d[a])

Python: from sys import stdin
from collections import deque
n = int(stdin.readline())
M = [[0] * (n + 1) for _ in range(n + 1)]
d = [200] * (n + 1)
def bfs():
    d[1] = 0
    dq = deque()
    dq.append(1)
    while len(dq) > 0:
        u = dq.popleft()
        for v in range(1, n + 1):
            if M[u][v] == 0 or d[v] != 200: continue
            d[v] = d[u] + 1
            dq.append(v)
    for i in range(1, n + 1):
        print(i, (-1 if d[i] == 200 else d[i]))
for u in range(1, n + 1):
    U = [int(j) for j in stdin.readline().split()]
    for v in U[2:]:
        M[u][v] = 1
bfs()

Python: n = int(input())
adj = [[0 for _ in range(n)] for _ in range(n)]
for i in range(n):
    l = list(map(int, input().split()))
    if l[1] == 0:
        continue 
    else:
        for j in range(2,len(l)):
            adj[l[0]-1][l[j]-1] = 1

color = ['white' for _ in range(n)]
d = [-1 for _ in range(n)]
color[0] = 'grey'
d[0] = 0
Q = [1]
while Q:
    u = Q.pop(0)
    color[u-1] = 'black'
    for v in range(1, n+1):
        if adj[u-1][v-1] == 1 and color[v-1] == 'white':
            Q.append(v)
            color[v-1] = 'grey'
            d[v-1] = d[u-1] + 1  

for i in range(n):
    print(' '.join([str(i+1), str(d[i])]))