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: # coding: utf-8

from queue import Queue

N = int(input())
graph = [None]
for _ in range(N):
    graph.append(list(map(int, input().split(" ")))[1:])

class BFSSolver:

    def __init__(self, graph):
        self.graph = graph
        self.queue = Queue()
        self.queue.put(1)
        self.before_id = 1
        self.already_searched = [1]
        self.res = [0]
        for _ in range(N):
            self.res.append(-1)
        self.res[1] = 0
        self.turn = 0

    def next_turn(self):
        now_id = self.queue.get()
        before_id = now_id
        neighbors = self.graph[now_id][1:]
        for i in neighbors:
            if i not in self.already_searched:
                self.turn = self.res[before_id] + 1
                self.already_searched.append(i)
                self.res[i] = self.turn
                self.queue.put(i)

    def solve(self):
        while not self.queue.empty():
            self.next_turn()

        for id, i in enumerate(self.res[1:]):
            print("{} {}".format(id+1, i))

s = BFSSolver(graph)
s.solve()

Python: #!/usr/bin/python3

def find(id, V, d, dist):
    i = id - 1
    dist[i] = d
    for v in V[i]:
        find(v, V, d + 1, dist)
    
n = int(input())
# [isFind, d, f]
A = [[False, 0, 0] for i in range(n)]
U = []
V = []
dist = [-1] * n
for i in range(n):
    l = list(map(int, input().split()))
    U.append(l[0])
    V.append(l[2:])

find(1, V, 0, dist)

for u in U:
    print(u, dist[u - 1])

Python: import collections

N = int(input())
UKV = [list(map(int,input().split())) for _ in range(N)]

dist = [-1]*N
que = collections.deque()

G = [[]]*N
for ukv in UKV:
    G[ukv[0]-1] = sorted(ukv[2:])

dist[0] = 0
que.append(1)

while len(que) != 0:
    v = que.popleft()
    for nv in G[v-1]:
        if dist[nv-1] != -1:
            continue
        dist[nv-1] = dist[v-1] + 1
        que.append(nv)

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

Python: # -*- coding: utf-8 -*-                                                                                                                                                                                                                               

def BFS(adj, start):
    n = len(adj)
    d = [n] * n
    flag = [0] * n
    Q = []

    Q.append(start)
    d[start] = 0

    while len(Q) != 0:
        u = Q.pop(0)
        v = [i for i, x in enumerate(adj[u]) if (x == 1) and (flag[i] == 0)] # v <= ??£??\???????????????????????¢?´¢??????????????????
        
        for i in v:
            Q.append(i)
            d[i] = min(d[u] + 1, d[i])
            flag[u] = 1
    
    for i in range(n):
        if d[i] == n:
            d[i] = -1

    return d

def main():
    n = int(input())
    adj = [[0 for i in range(n)] for j in range(n)]
    
    for i in range(n):
        tmp = list(map(int, input().split()))
        u = tmp[0]
        u = u -1
        k = tmp[1]
        v = tmp[2:]
        for j in range(k):
            adj[u][v[j]-1] = 1
    
    d = BFS(adj, 0)
    for i in range(n):
        print(i+1, d[i])


if __name__ == "__main__":
    main()

Python: from collections import deque
u = int(input())
g = [[i for i in map(int, input().split())] for _ in range(u)]
graph = [[] for _ in range(u)]
ans = [-1] * u
for i in range(u):
    for j in range(g[i][1]):
        graph[i].append(g[i][2 + j] - 1)
que = deque()
que.append(0)
ans[0] = 0
while que:
    v = que.popleft()
    for nv in graph[v]:
        if ans[nv] != -1:
            continue
        ans[nv] = ans[v] + 1
        que.append(nv)

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

Python: def MAIN():
    n = int(input())
    li = [[] for _ in range(n + 1)]
    ans = [[i, 0] for i in range(n + 1)]
    for _ in range(n):
        u, k, *v = map(int, input().split())
        li[u] = v
    dp = [1]
    while dp:
        u = dp.pop()
        for v in li[u]:
            if ans[v][1] == 0:
                ans[v][1] = ans[u][1] + 1
                dp.append(v)
    for d in ans[1:]:
        print(*d)
MAIN()

Python: n = int(input())
 
adj = [None]
for i in range(n):
    adji = list(map(int, input().split()[2:]))
    adj.append(adji)
isSearched = [None] + [False] * n
distance = [None] + [-1] * n
def BFS(u):
    d = 0
    isSearched[u] = True
    distance[u] = d
    edge = [u]
    while edge:
        q = list(edge)
        edge = []
        d += 1
        for ce in q:
            for ne in adj[ce]:
                if not isSearched[ne]:
                    isSearched[ne] = True
                    edge.append(ne)
                    distance[ne] = d
BFS(1)
for i, x in enumerate(distance[1:], start=1):
    print(i, x)

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()

Python: from collections import deque
n=int(input())
edge=[[] for _ in range(n+1)]
for i in range(n):
  v,k,*u=map(int,input().split())
  edge[v]=u
p=[-1]*(n+1)
p[1]=0
q=deque([])
q.append(1)
v=[1]*(n+1)
v[1]=0
while q:
  now=q.popleft()
  for i in edge[now]:
    if v[i]:
      q.append(i)
      p[i]=p[now]+1
      v[i]=0
for i in range(1,n+1):
  print(i,p[i])