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: m = [[0 for _ in range(n+1)] for _ in range(n+1)]
mm = [[] for _ in range(n+1)]

n = int(input())
for _ in range(n):
	tmp = [int(x) for x in input().split()]
	u,k,l = tmp[0],tmp[1],tmp[2:]
	mm[u] += tmp[2:]
	for x in l:
		m[u][x] = 1
		
dp = [float('inf') for _ in range(n+1)]
queue = [1]

while queue:
	t = queue.pop(0)
	for x in mm[t]:
		if dp[x] > dp[t] + 1:
			dp[x] = dp[t] + 1
			queue.append(x)
		else:
			pass
			
for i,x in enumerate(queue):
	if i == 0:
		pass
	else:
		if x == float('inf'):
			print(i, -1)
		else:
			print(i, x)

Python: n = int(input())
graph = [[0 for i in range(n)] for j in range(n)]
d = [0] * n
f = [0] * n
queue = [0]


for i in range(n):
   a = list(map(int, input().split()))
   for j in range(0, a[1], 1):
       graph[a[0] - 1][a[2 + j] - 1] = 1

f[0] = 1
while len(queue) != 0:
    i = queue.pop(0)
    for j in range(n):
        if (graph[i][j] == 1) & (f[j] == 0):
            queue.append(j)
            f[j] = 1
            d[j] = d[i] + 1

[print(i+1, d[i] if (i == 0) | (d[i] != 0) else -1) for i in range(n)]

Python: # -*- coding: utf-8 -*-
'''
所要時間は、分位であった。
'''


# ライブラリのインポート
#import re #正規表現
import sys
#import heapq
#import bisect
from collections import deque
#import math

def main():
    inf = 10000
    n = int(input())
    D = [inf for i in range(n)]
    L = [[] for i in range(n)]
    for i, line in enumerate(sys.stdin):
        L[i] = list(map(lambda x: int(x)-1, list(line.strip("\n").split())))

    q = deque([0])
    D[0] = 0
    while(len(q)):
        u = q.popleft()
        if L[u][1] == -1:
            continue
        for j in range(2,len(L[u])):
            if D[L[u][j]] == inf:
                q.append(L[u][j])
            D[L[u][j]] = min(D[L[u][0]] + 1, D[L[u][j]]) 

                      
    for i in range(n):
        print("{} {}".format(i+1,D[i])) if D[i] < inf else print("{} {}".format(i+1,-1))
            
if __name__ == '__main__':
    main()

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