Go: package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)

	g := make([][]int, n+1)
	d := make([]int, n+1)
	for i := 0; i < n; i++ {
		var u,k int
		fmt.Scan(&u)
		fmt.Scan(&k)
		g[u] = make([]int, k)
		for j := 0; j < k; j++ {
			fmt.Scan(&g[u][j])
		}

		d[i+1] = -1
	}

	q := [][]int{}
	q = append(q, []int{1, 0})
	for len(q) > 0 {
		pop := q[0]
		if len(q) > 1 {
			q = q[1:]
		} else {
			q = [][]int{}
		}
		if d[pop[0]] >= 0 {
			continue
		}
		d[pop[0]] = pop[1]

		for j := 0; j < len(g[pop[0]]); j++ {
			q = append(q, []int{g[pop[0]][j], pop[1]+1})
		}
	}

	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d\n", i, d[i])
	}
}

Python: INF = float('inf')

v = int(input())
graph = [None]

for i in range(v):
    u = list(map(int, input().split()))
    
    graph.append(u[2:])

visited = [False] * (v+1)
visited[1] = True
cost = [INF] * (v+1)
cost[1] = 0
c = 0

q = graph[1]

while q:
    c += 1
    q_next = []
    for u in q:
        if not visited[u]:
            visited[u] = True
            cost[u] = c
            q_next.extend(graph[u])
    q = q_next
    
for i in range(v):
    if cost[i+1] == INF: cost[i+1] = -1
    print(i+1, cost[i+1])

Python: from collections import deque
N=int(input())
color=["white"]*(N+1)
rinsetu=[[] for i in range(N+1)]
for i in range(N):
    a,*b=list(map(int,input().split()))
    for idx,j in enumerate(b):
        if idx==0:continue
        rinsetu[a].append(j)
distance=[10**5]*(N+1)
distance[1]=0
def bfs():
    d = deque()
    d.append(1)
    while(d):
        num=d.popleft()
        color[num] = "black"
        for i in rinsetu[num]:
            if color[i]=="white":
                d.append(i)
                distance[i]=min(distance[num]+1,distance[i])

bfs()
for i in range(1,N+1):
    if distance[i]==10**5:distance[i]=-1
    print(i,distance[i])

Python: N= int(input())
E = [input().split()[2:] for _ in [0]*N]
Q = [0]
L = [0] + [-1]*N

    


while Q:
    top = Q.pop(0)
    for i in E[top]:
        i = int(i) - 1
        if L[i] < 0 :L[i] = L[top] +1 ; Q+= [i]

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

Python: n = int(input())
l = [[] for i in range(n)]
retval=[10**10 for i in range(n)]



for i in range(n):
    _input = [int(j) - 1 for j in input().split(" ")]
    u = _input[0]
    k = _input[1] + 1
    node = sorted(_input[2::])
    if u in node:
        node.remove(u)
    l[u] = node

retval[0]=0
for step in range(n+1):
    for i ,d in enumerate(retval):
        if d==step:
            for node in l[i]:
                retval[node]=min(retval[node],step+1)

for i,d in enumerate(retval):
    if d==10**10:
        print(i+1,-1)
    else:
        print(i+1,d)

Python: # 幅優先探索 Breadth first search: BFS
import queue

n = int(input())
Adj = [[] for i in range(n)]
for i in range(n):
    dat = [int(i) for i in input().split()]
    Adj[dat[0] - 1] = dat[2:]

D = [-1 for i in range(n)]
D[0] = 0
Q = queue.Queue()
Q.put(1)
while not Q.empty():
    u = Q.get()
    for v in Adj[u - 1]:
        if D[v - 1] == -1:
            Q.put(v)
            D[v - 1] = D[u - 1] + 1

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

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

while Q:top = Q.pop();func(top)

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

Python: import sys
import queue
input = sys.stdin.readline
n = int(input())
g = [[] for _ in range(n+1)]
d = [-1 for _ in range(n+1)]
for _ in range(n):
    c = list(map(int,input().split()))
    g[c[0]] = c[2:]

depth = 0
q = queue.Queue()
p = queue.Queue()
q.put(1)
while not q.empty():
    while not q.empty():
        s = q.get()
        if d[s] < 0:
            d[s] = depth
            for i in g[s]:
                p.put(i)
    p, q = q, p
    depth += 1

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

Python: N= int(input())
E = [input().split()[2:] for _ in range(N)]
Q = [0]
L = [0] + [-1]*N
frag = [1] + [0]*N
def func(ide):
    global Q
    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:pass
    

while Q:top = Q[0];func(top);del Q[0]

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

Python: import sys
from collections import deque

sys.setrecursionlimit(50000)

n = int(input())

data = [[] for _ in range(n)]
answer = [-1]*n
answer[0] = 0
for i in range(n):
    line = list(map(int, input().split(" ")))
    if line[1] != 0:
        for e in line[2:]:
            data[i].append(e)


def bfs(vs, count=0):
    next_vs = []
    for v in vs:
        for n_v in data[v-1]:
            if answer[n_v-1] == -1:
                answer[n_v-1] = count+1
                next_vs.append(n_v)
    if not next_vs == []:
        bfs(next_vs, count+1)


bfs([1])

for i in range(n):
    line = str(i+1) + " " + str(answer[i])
    print(line)

Python: import sys
from collections import deque

sys.setrecursionlimit(10 ** 7)
input = sys.stdin.readline
f_inf = float('inf')
mod = 10 ** 9 + 7


def resolve():
    n = int(input())
    edge = [[] for _ in range(n)]
    for _ in range(n):
        u, k, *V = map(int, input().split())
        for v in V:
            edge[u - 1].append(v - 1)

    depth = [f_inf] * n
    depth[0] = 0
    que = deque([0])
    while que:
        v = que.popleft()
        for u in edge[v]:
            if depth[u] == f_inf:
                depth[u] = depth[v] + 1
                que.append(u)

    for i in range(n):
        print(i + 1, depth[i] if depth[i] != f_inf else -1)


if __name__ == '__main__':
    resolve()

Python: import sys
# sys.stdin = open('input.txt')
from collections import deque

def fillMatrix():
    for i in range(n):
        u, k, *v = map(int, input().split())
        for j in v:
            matrix[i][j-1] = 1

def bfs(s):
    status[s] = VISITING
    distance[s] = 0
    Q.append(s)
    while len(Q) > 0:
        u = Q.popleft()
        for v in range(n):
            if matrix[u][v] and status[v] == NOT_VISITED:
                status[v] = VISITING
                distance[v] = distance[u] + 1
                Q.append(v)
        status[u] = VISITED

n = int(input())
matrix = [[0]*n for i in range(n)]
INFTY = 1 << 21
distance = [INFTY] * n

NOT_VISITED = 0 # WHITE
VISITING = 1 # GRAY
VISITED = 2 # BLACK
status = [NOT_VISITED] * n
Q = deque()

fillMatrix()
bfs(0)

for i in range(n):
    ans = []
    ans.append(i+1)
    if distance[i] == INFTY:
        distance[i] = -1
    ans.append(distance[i])
    ans = map(str, ans)
    print(' '.join(ans))

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 = [-1 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 and dis[k] == -1:
         dis[k] = dis[s] + 1
         bfs_visit(k)

for s in range(n):
    bfs_visit(s)
for s in range(n):
    print (s+1,dis[s])

Python: 
n = int(input())
X = []
for _ in range(n):
    x = list(map(int, input().split()))
    if x[1] == 0:
        X.append([])
    else:
        X.append(x[2:])
Y = [-1 for _ in range(n)]
def search(i = 0, d = 0):
    if Y[i] > d or Y[i] < 0:
        Y[i] = d
        for x in X[i]:
            search(x - 1, d + 1)
    
search()

for i, y in enumerate(Y):
    print('{} {}'.format(i + 1, y))