Go: package main

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

type Queue []int

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

func (q *Queue) pop() int {
	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([]int, 0))
	queue.push(1)
	paths[1] = 1

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

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

Python: from collections import deque

n = int(input())
graph = [[] for _ in range(n + 1)]
for _ in range(n):
    input_list = list(map(int, input().split()))
    index = input_list[0]
    num = input_list[1]

    if num >= 1:
        nodes = input_list[2:]
        for node in nodes:
            graph[index].append(node)
            # graph[node].append(index)

visited = [-1] * (n + 1)
num = [-1] * (n + 1)
q = deque()
visited[1] = 1
num[1] = 0
q.append(1)

while q:
    index = q.popleft()
    
    for node in graph[index]:
        if visited[node] == -1:
            visited[node] = 1
            num[node] = num[index] + 1
            q.append(node)


for i, j in enumerate(num):
    if i == 0:
        continue
    print(i, j)

Python: N= int(input())
E = [input().split()[2:] for _ in range(N)]
frag, T, L,Q = [0]*N, [0]*N, [0]*N, [0]
frag[0] = 1
def func(ide):
    for i in E[ide]:
        i = int(i) - 1
        if frag[i] != 1:frag[i] = 1;L[i] = L[ide] +1 ;Q.append(i) 
        else:return

while Q:top = Q[0];func(top);del Q[0]
    
for i in range(1,N):
    if int(L[i]) == 0:
        L[i] = -1

for i in range(N):print(i + 1 ,int(L[i]))

Python: #from collections import deque
import sys

readline = sys.stdin.readline
sys.setrecursionlimit(10**6)

#def mypopleft(que, index):
#    if len(que) > index:
#        return que.pop(index)
#    else:
#        return []


def main():
    # input
    n = int(input())

    graph = []
    for i in range(n):
        u, k, *tmp = [int(i) for i in readline().split()]
        graph.append(tmp)
    
    #print(graph)
    d = [-1]*n
    #que = deque([1])
    que = [1]
    #count = 0
    d[0] = 0
    check = []

    while True:
        v = que.pop(0)
        #print(v)
        #count += 1
        #print(d)
        for u in graph[v-1]:
            #print(u)
            if d[u-1] == -1:
                d[u-1] = d[v-1] + 1
                que.append(u)
        if len(que) == 0:
            break
    
    for i in range(n):
        print("{} {}".format(i+1, d[i]))


if __name__ == "__main__":
    main()

Python: from sys import maxsize


def read_adj():
    n = int(input())
    adj_list = [[] for _ in range(n + 1)]
    for _ in range(1, n + 1):
        u, _, *adj = [int(x) for x in input().split()]
        adj_list[u] = adj
    return n, adj_list


def shortest_paths(n, adj_list, ini_key):
    dist = [maxsize] * (n + 1)

    S = [ini_key]
    dist[ini_key] = 0

    while S != []:
        key = S.pop()
        d = dist[key] + 1
        for k in adj_list[key]:
            if d < dist[k]:
                dist[k] = d
                S.append(k)

    return dist


def print_dist(n, dist):
    for i in range(1, n + 1):
        if dist[i] == maxsize:
            print(i, -1)
        else:
            print(i, dist[i])


def main():
    n, adj_list = read_adj()
    dist = shortest_paths(n, adj_list, 1)
    print_dist(n, dist)


if __name__ == '__main__':
    main()

Python: n = int(input())
G = {}
D = [-1] * n
for _ in range(n):
    A = list(map(int, input().split()))
    G[A[0] - 1] = [a - 1 for a in A[2:]]

# print(G)

q = [(0, 0)]
while len(q) > 0:
    v, d = q[0]
    del q[0]
    if D[v] >= 0:
        continue
    D[v] = d

    for nv in G[v]:
        q.append((nv, d+1))

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

Python: from collections import deque

N = int(input())
graph = {i:[] for i in range(N)}

for i in range(N):
    g = list(map(int, input().split()))
    for j in range(g[1]):
        graph[g[0]-1].append(g[j+2]-1)
        
que = deque()
dist = [-1 for _ in range(N)]
que.append(0)
dist[0] = 0

while que:
    top = que.popleft()
    
    for i in graph[top]:
        if(dist[i] != -1):
            continue
        dist[i] = dist[top]+1
        que.append(i)

for i in range(len(dist)):
    print(i+1, dist[i])

Python: n = int(input())
v = []
for i in range(n):
    v_i = list(map(int,input().split()))[2:]
    v.append(v_i)
    
d = [-1]*n
d[0]=0
queue = [1]
dis = 1
while len(queue)!=0:
    queue2 = []
    for i in queue:
        for nex in v[i-1]:
            if d[nex-1]==-1:
                d[nex-1]=dis
                queue2.append(nex)
    dis +=1
    queue = queue2

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

Python: # -*- coding: utf-8 -*-
from collections import deque


class Graph:
    def __init__(self, n, adj_matrix):
        self.n = n
        self.adj_matrix = adj_matrix

    def show(self):
        for _ in self.adj_matrix:
            print(*_)

    def dfs(self):
        self.states = [2] * self.n
        self.d = [None] * self.n
        self.f = [None] * self.n
        self.time = 0

        for u in range(self.n):
            if self.states[u] == 2:
                self.dfs_visit(u)

    def dfs_visit(self, u):
        self.states[u] = 1
        self.time += 1
        self.d[u] = self.time

        for v, edge in [(v, edge) for v, edge in enumerate(self.adj_matrix[u])
                        if edge]:
            if self.states[v] == 2:
                self.dfs_visit(v)

        self.states[u] = 0
        self.time += 1
        self.f[u] = self.time

    def show_dfs(self, start=0):
        self.dfs()
        for i, (d, f) in enumerate(zip(self.d, self.f)):
            print(i + 1, d, f)

    def bfs(self, start):
        self.states = [1] * self.n
        self.dists = [float('inf')] * self.n

        queue = deque([start])
        self.dists[start] = 0
        while queue:
            u = queue.popleft()
            edges = self.adj_matrix[u]

            for v, edge in [(v, edge) for v, edge in enumerate(edges) if edge]:
                if self.dists[v] > self.dists[u] + 1:
                    self.dists[v] = self.dists[u] + 1
                queue.append(v)

        self.dists = [
            -1 if dist == float('inf') else dist for dist in self.dists
        ]

    def show_bfs(self, start=0):
        self.bfs(start=start)
        for i, dist in enumerate(self.dists):
            print(i + 1, dist)


if __name__ == '__main__':
    n = int(input())
    adj_matrix = [[0] * n for i in range(n)]
    for i in range(n):
        for v in input().split()[2:]:
            adj_matrix[i][int(v) - 1] = 1

    g = Graph(n, adj_matrix)
    g.show_bfs()