Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, &g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

func fillDistancesByBreadthFirstSearch(g *DirectedGraph, startNode *DirectedGraphNode) {
	startNode.visited = true
	startNode.d = 0

	queue := Queue{}
	queue.enqueue(startNode)
	for !queue.isEmpty() {
		u := queue.dequeue().node
		for _, adjacent := range u.adjacents {
			if !adjacent.visited {
				adjacent.visited = true
				adjacent.d = u.d + 1
				adjacent.parent = u
				queue.enqueue(adjacent)
			}
		}
		u.visited = true
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	// fmt.Println(g)
	fillDistancesByBreadthFirstSearch(g, &g.nodes[1])
	// fmt.Println(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		distance := node.d
		if distance == infty {
			distance = -1
		}
		fmt.Println(node.key, distance)
	}
}

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
input:
4
1 2 2 4
2 1 4
3 0
4 1 3

output:
1 0
2 1
3 2
4 1
"""

import sys
from collections import deque

UNVISITED, VISITED_IN_QUEUE, POPPED_OUT = 0, 1, 2


def generate_adj_matrix(v_info):
    for v_detail in v_info:
        v_index, adj_num, *adj_list = map(int, v_detail)
        # assert len(adj_list) == adj_num
        init_adj_table[v_index].extend(adj_list)
    return init_adj_table


def graph_bfs(v_init):
    status[v_init] = VISITED_IN_QUEUE
    distance[v_init] = 0
    queue.appendleft(v_init)

    while queue:
        current = queue.popleft()
        for v in adj_table[current]:
            if status[v] is UNVISITED:
                status[v] = VISITED_IN_QUEUE
                distance[v] = distance[current] + 1
                queue.append(v)
        status[current] = POPPED_OUT
    return distance


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertices_num = int(_input[0])
    vertices_info = list(map(lambda x: x.split(), _input[1:]))
    init_adj_table = [[] for _ in range(vertices_num + 1)]
    # assert len(vertex_info) == vertex_num

    # config length = (vertex_num + 1)
    queue = deque()
    status = [UNVISITED] * (vertices_num + 1)
    distance = [-1] * (vertices_num + 1)

    adj_table = generate_adj_matrix(vertices_info)
    ans = graph_bfs(1)
    for k, v in enumerate(ans[1:], 1):
        print(k, v)

Python: from sys import stdin
from collections import deque

def read_graph(n):
    A = [ [0]*(n+1) for _ in range(n+1) ]
    for _ in range(n):
        line = deque(stdin.readline().strip().split())
        i = line.popleft()
        line.popleft()
        for k in line:
            A[int(i)][int(k)] = 1
    return A

def bfs_ctrl(n, A):
    color = ["WHITE"] * (n+1)
    d = [-1] * (n+1)
    Q = deque([])

    def bfs(s):
        nonlocal color
        nonlocal d
        nonlocal Q
        color[s] = "GRAY"
        d[s] = 0
        Q.append(s)

        while Q:
            u = Q.popleft()
            for v in range(1, n+1):
                if A[u][v] and color[v] == "WHITE":
                    color[v] = "GRAY"
                    d[v] = d[u] + 1
                    Q.append(v)

            color[u] = "BLACK"

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

n = int(input())
A = read_graph(n)
bfs_ctrl(n, A)

Python: from collections import deque
INF = 1145141919810364364334
s = [None]
r = [None]

n = int(input())
for _ in range(n):
    temp = list(map(int,input().split()))
    s.append(temp[2:])
    
d = [INF] * (n+1)

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

while q:
    x = q.popleft()
    for i in s[x]:
        if d[i] == INF:
            q.append(i)
            
        d[i] = min(d[x] + 1 , d[i])
        
for i in range(1,n+1):
    if d[i] == INF:
        d[i] = -1
    print(i,d[i])

Python: def main():
    import sys
    N = int(sys.stdin.readline())
    L1 = [list(map(int, sys.stdin.readline().split())) for i in range(N)]
    L = [[] for _ in range(N+1)]
    for row in L1:
        L[row[0]] += row[2:]
    #print(L)
    
    d = [-1 for i in range(N+1)] #距離
    def bfs(p, queue=[]):
        queue+=[p]
        d[p]=0
        while queue:
            now = queue.pop(0)
            for ch in L[now]:
                if d[ch] ==-1: #未開
                    d[ch] = d[now]+1
                    queue +=[ch]
    
    
    bfs(1)
    for idx, ans in enumerate(d[1:]):
        print(idx+1, ans)


if __name__=='__main__':
    main()

Python: from collections import deque


def bfs(root):
    Q = deque()
    distance[root] = 0
    Q.append(root)
    i = root
    while len(Q) > 0:
        i = Q.popleft()
        for v in range(n):
            if adjMat[i][v] == 1 and color[v] == 'white':
                Q.append(v)
                color[v] = 'gray'
                distance[v] = distance[i] + 1
        color[i] = 'black'


n = int(input())
adjMat = [[0] * n for _ in range(n)]
color = ['white'] * n
distance = [-1] * n

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

bfs(0)

for i in range(n):
    out = ''
    out += '{} {}'.format(i + 1, distance[i])
    print(out)

Python: from collections import deque

n = int(input())                #エッジの個数
edge = [[] for _ in range(n)]   #エッジの隣接リスト（お隣さんを格納する）

for _ in range(n):
  u, _, *v = map(lambda x: int(x)-1, input().split())
  edge[u] = sorted(v)           #入力された隣接頂点をお隣さんリストに格納

dist = [-1] * n                #始点から各頂点iまでの距離を測るリスト
dist[0] = 0                    #0番目のエッジの距離
Q = deque([0])                 #次に訪問すべきエッジを記録するキュー

while len(Q):
  v = Q.popleft()             #vに次に訪問するエッジを代入（v=自分）
  for c in edge[v]:           #v(自分)のお隣さんの数分だけイテレーション
    if dist[c] == -1:         #もしお隣さんお距離が-1になっていたら
      dist[c] = dist[v] + 1   #お隣さんの距離=自分の距離+1にする
      Q.append(c)             #次に訪問すべきキューにお隣さんを代入

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