Go: package main

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

type Pair struct {
	v int
	d int
}

type Queue []Pair

func (q *Queue) push(v Pair) {
	*q = append(*q, v)
}

func (q *Queue) pop() Pair {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

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

	nVerts := scanInt(sc)
	graph := make([][]int, nVerts+1)

	for i := 0; i < nVerts; i++ {
		u := scanInt(sc)
		nDegrees := scanInt(sc)

		graph[u] = make([]int, nDegrees)
		for d := 0; d < nDegrees; d++ {
			graph[u][d] = scanInt(sc)
		}
	}

	paths := make([]int, nVerts+1)

	queue := Queue(make([]Pair, 0))
	queue.push(Pair{1, 1})
	paths[1] = 1

	for len(queue) > 0 {
		p := queue.pop()
		d := p.d + 1
		for _, v := range graph[p.v] {
			if paths[v] == 0 {
				paths[v] = d
				queue.push(Pair{v, d})
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= nVerts; i++ {
		fmt.Fprintf(w, "%d %d\n", i, paths[i]-1)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

Python: n = int(raw_input())
G = [[0 for i in range(n+1)] for j in range(n+1)]
d = [-1 for i in range(n+1)]

for i in range(n):
    v = map(int, raw_input().split())
    for j in range(v[1]):
        G[v[0]][v[2+j]] = 1

flag = [0 for i in range(n+1)]
tn = [[0 for i in range(n+1)] for j in range(n+1)]
tn[0][1] = 1
r = 0
for i in range(n):
    for j in range(1, n+1):
        if flag[j] == 0 and tn[i][j] == 1:
            flag[j] = 1
            d[j] = r
            for k in range(1, n+1):
                if G[j][k] == 1:
                    tn[i+1][k] = 1
    r += 1

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

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.pop()
        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: #!/usr/bin/env python
# -*- coding: utf-8 -*-

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_adj_list = v_detail[2:]
        # assert len(v_adj_list) == int(v_detail[1])
        for each in v_adj_list:
            init_adj_matrix[int(v_detail[0]) - 1][int(each) - 1] = 1
    return init_adj_matrix


def graph_bfs(v_init):
    vertices_status_list[v_init] = VISITED_IN_QUEUE
    vertices_distance_list[v_init] = 0
    vertices_visit_queue.appendleft(v_init)

    while vertices_visit_queue:
        current_vertex = vertices_visit_queue.popleft()
        for v in range(1, vertices_num + 1):
            if adj_matrix[current_vertex - 1][v - 1] and vertices_status_list[v] is UNVISITED:
                vertices_status_list[v] = VISITED_IN_QUEUE
                vertices_distance_list[v] = vertices_distance_list[current_vertex] + 1
                vertices_visit_queue.appendleft(v)
        vertices_status_list[current_vertex] = POPPED_OUT
    return vertices_distance_list


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

    # config length = (vertex_num + 1)
    vertices_visit_queue = deque()
    vertices_status_list = [UNVISITED] * vertices_num
    vertices_status_list.insert(0, -1)
    vertices_distance_list = [-1] * (vertices_num + 1)

    adj_matrix = generate_adj_matrix(vertices_info)
    ans = graph_bfs(v_init=1)
    for j in range(vertices_num):
        print(j + 1, ans[j + 1])

Python: # your code goes here
#Breadth First Search
n=int(input())
V=[]
a=[]
for i in range(n):
    V.append([int(i) for i in input().split()])
    a.append(0)
    V=sorted(V,key=lambda x:x[0])
print('1 0')
d=1
c=0
w=[0]
p=[]
while c<n and w!=[]:
    i=0
    y=[]
 #   print(c)
    while c<n and i<len(w):
        j=2
        while j<2+V[w[i]][1] and c<n:
            if a[V[w[i]][j]-1]==0:
        #        print(a)
                a[V[w[i]][j]-1]=1
                p.append([V[w[i]][j],d])
                c+=1
                y.append(V[w[i]][j]-1)
            j+=1
        i+=1
    w=y
    d+=1
p=sorted(p, key=lambda x:x[0])
#print(p)
i=2
j=0
while i <=n and j<len(p):
    while p[j][0]>i:
        print(str(i) +" -1")
        i+=1
    print(str(p[j][0])+" "+str(p[j][1]))
    i+=1
    j+=1
while i<=n:
    print(str(i)+" -1")
    i+=1

Python: N=int(input())
List = [[] for i in range(N+1)]
for i in range(N):
    l=list(map(int,input().split()))
    List[l[0]]=l[2:]
#print(List)
D=[10**9 for i in range(N+1)]

Q=[[0,1]]
for i in range(10**9):
    if len(Q)==i:
        break
    if D[Q[i][1]]==10**9:
        D[Q[i][1]]=Q[i][0]
        for j in List[Q[i][1]]:
            if D[j]==10**9:
                Q.append([Q[i][0]+1,j])
for i in range(1,N+1):
    if D[i]==10**9:
        print(i,-1)
    else:
        print(i,D[i])

Python: import collections
n = int(input())
G = []
for i in range(n):
    T = [0]*n
    G.append(T)
for i in range(n):
    L = list(map(int,input().split()))
    for j in range(2,len(L)):
        G[i][L[j]-1] += 1
d = [float('inf')]*n
q = collections.deque()
q.append(0)
d[0] = 0
while len(q) > 0:
    start = q.popleft()
    for i in range(n):
        if G[start][i] == 1:
            if d[i] == float('inf'):
                q.append(i)
                d[i] = d[start]+1
for i in range(n):
    if d[i] != float('inf'):
        print(i+1,d[i])
    else:
        print(i+1,-1)

Python: n=int(input())
e=[[] for _ in range(n)]
for _ in range(n):
    u,_,*v=map(lambda x:int(x)-1, input().split())
    e[u]=sorted(v)
q=[0]
d=[-1]*n
d[0]=0
while q:
    i=q.pop(0)
    for v in e[i]:
        if d[v]==-1:
            q.append(v)
            d[v]=d[i]+1
for i in range(n):
    print(i+1,d[i])

Python: from sys import stdin
from collections import deque
n = int(input())
d = [-1] * (n + 1)
def bfs():
    d[1] = 0
    dq = deque([1])
    while len(dq) != 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] != -1 : continue
            d[c] = d[v] + 1
            dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
G = [0] + [list(map(int, inpput().split()[2:])) for i in range(n)]
bfs()

Python: n = int(raw_input())
  
G = [0 for i in range(n)] 
a = [[0 for i in range(n)] for j in range(n)]
dis = [99999 for i in range(n)]
dis[0] = 0
 
for i in range(n):
    G = map(int, raw_input().split())
    for j in range(G[1]):
        a[G[0]-1][G[2+j]-1] = 1
  
def bfs_visit(s):
    for k in range(n):
      if a[s][k] == 1:
       if dis[k] > dis[s]+1:
         dis[k] = dis[s]+1
         bfs_visit(k)
 
for s in range(n):
    bfs_visit(s)
for s in range(s):
    if dis[s] == 99999:
       dis[s] = -1
for s in range(n):
    print (s+1,dis[s])