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) {
			if !dl.isVisited(v) {
				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())
g = []
# ans = [[-1]*n for _ in range(n)]
ans = [-1] * n
done = set()
q = deque()

for i in range(n):
    temp = list(map(int, input().split()))
    g.append(temp[2:])

# print(g)

q.append(0)
# dis = 1
ans[0] = 0
done.add(1)

while q:
    idx = q.popleft()
    adj = g[idx]
    # print('node:', idx+1)

    for i in adj:
        if i not in done:
            ans[i-1] = ans[idx] + 1
            done.add(i)
            q.append(i-1)
    # if len(adj) > 0:
    #     dis += 1

# print(ans)

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

Python: 
v = int(input())
vlist = [0]*v
for num in range(v):
    temp = list(map(int,input().split()))
    if temp[1] != 0:
        vlist[num] = temp[2:]
deep = [0]+[-1]*(v-1)
waiting = [1]

while waiting:
    vertex = waiting.pop(0)
    if vlist[vertex-1]:
        for subv in vlist[vertex-1]:
            if deep[subv-1] == -1:
                deep[subv-1] = deep[vertex-1]+1
                waiting += [subv]

count = 0
for num in deep:
    count += 1
    print(count,num)

Python: from collections import deque
N = input()
d = [float('inf')] * N
m = [[] for i in xrange(N)]
Q = deque([])

def bfs(s):
    Q.append(s)
    d[s] = 0

    while(len(Q) != 0):
        u = Q.popleft()
        for v in m[u]:
            if( d[v] == float('inf')):
                d[v] = d[u] + 1
                Q.append(v)

if __name__ == '__main__':

    for i in range(N):
        v = map(int, raw_input().split())
        for j in v[2:]:
            m[i].append(j-1)
    
    bfs(0)

    for i in range(N):
        if d[i] == float('inf'):
            d[i] = -1
        print (i+1), d[i]

Python: from collections import deque

n = int(input())
G = []
checked = [False for i in range(n + 1)]
d = [-1 for i in range(n + 1)]
G.append([])
for i in range(n):
    u, k, *v = map(int, input().split())
    G.append(v)

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

while q:
    current = q.pop()
    for adj in G[current]:
        if not checked[adj]:
            q.append(adj)
            checked[adj] = True
            d[adj] = d[current] + 1

for id in range(1, n + 1):
    print("{0} {1}".format(id, d[id]))

Python: #coding:utf-8
n = int(input())
Q = [1]
M = [[False for i in range(n)] for j in range(n)]
dataList = []
for i in range(n):
    data = list(map(int,input().split()))
    dataList.append(data)
    for j in range(data[1]):
        v = data[j+2] - 1
        M[i][v] = True
color = ["white" for i in range(n)]
d = [-1 for i in range(n)]
d[0] = 0
while Q != []:
    u = Q.pop() - 1
    color[u] = "gray"
    data = dataList[u]
    for i in range(data[1]):
        v = data[i+2] - 1
        if M[u][v] == True and color[v] == "white":
            d[v] = d[u] + 1
            Q.append(v+1)
    color[u] = "black"

print(" ".join([str(num) for num in d]))

Python: #!/usr/bin/env python3

import sys
# SimpleQueue でOKなのだが AOJ の環境では Python3.7 が使えない
from queue import Queue


class BFS():
    INFTY = sys.maxsize

    def __init__(self, M, n, debug=False):
        self.M = M
        self.n = n
        # 距離で訪問状態(color)を管理する
        self.d = [self.INFTY] * n
        self.debug = debug

    def bfs(self, s):
        q = Queue()
        q.put(s)
        self.d[s] = 0
        self.debug_print(q)

        while not q.empty():
            u = q.get()
            for v in range(self.n):
                if self.M[u][v] == 0:
                    continue
                if self.d[v] != self.INFTY:
                    continue
                self.d[v] = self.d[u] + 1
                q.put(v)
                self.debug_print(q)

        for i in range(self.n):
            if self.d[i] == self.INFTY:
                d = -1
            else:
                d = self.d[i]
            print(f'{i+1} {d}')

    def debug_print(self, q):
        if not self.debug:
            return
        print('d: ', self.d)
        print('q: ', q.queue)
        print('-------------------------')


def main():
    n = int(input())
    M = [[0] * n for _ in range(n)]

    for i in range(n):
        line = input()
        inputs = [int(x) for x in line.split(' ')]
        u = inputs.pop(0)
        u -= 1                  # 0 オリジンへ変換
        _ = inputs.pop(0)       # k （使わない...）
        for v in inputs:
            v -= 1              # 0 オリジンへ変換
            M[u][v] = 1

    BFS(M, n).bfs(0)


if __name__ == '__main__':
    main()

Python: import collections
n=int(input())
l=[]
for i in range(n):
  l1=list(map(int,input().split()))
  l2=[]
  if l1[1]==0:
    l2=["0" for j in range(n)]
  else:
    for j in range(n):
      if j+1 in l1[2:]:
        l2.append("1")
      else:
        l2.append("0")
  l.append(l2)
D=[-1 for i in range(n)]
D[0]=0
q=collections.deque()
q.append(0)
while len(q)!=0:
  cur=q.popleft()
  for d in range(n):
    if l[cur][d]=="1" and D[d]==-1:
      D[d]=D[cur]+1
      q.append(d)
for i in range(n):
  print(i+1,D[i])

Python: import queue,sys
N=int(input())
M=[list(map(int,e.split()[2:]))for e in sys.stdin]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v-=1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])