Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

Python: from collections import deque

N = int(input())

nodes = [tuple(map(int, input().split(' '))) for _ in range(N)]

distances = [-1] * (N + 1)

queue = deque()
queue.append((1, 0))

while len(queue) > 0:
    node, distance = queue.popleft()
    if distances[node] != -1:
        continue
    distances[node] = distance

    neighbors = nodes[node - 1][2:]
    for neighbor in neighbors:
        queue.append((neighbor, distance + 1))

for node in range(1, N + 1):
    print(node, distances[node])

Python: #coding: utf-8
inf = 100000000
n = int(input())

List = [0] + [list(map(int,input().split())) for i in range(n)]
color = [0] + ["white" for  i in range(n)]
d = [inf for i in range(n+1)]

s = 1
Q = [s]
d[s] = 0
while Q != []:
    q = Q.pop()
    if color[q] == "white":
        k = List[q][1]
        if k != 0:
            Q += List[q][2:2+k]
            for i in List[q][2:2+k]:
                d[i] = min(d[q] + 1, d[i])
    
    color[q] = "black"


for i, dis in enumerate(d[1:], 1):
    if dis == inf:
        dis = -1
    print(i, dis)

Python: # coding: utf-8
import queue

q = queue.Queue()
A = [[]*101 for _ in range(101)]
d = [-1]*101
visited = [False]*101

n = int(input().rstrip())
for i in range(n):
    line = [int(j) for j in input().rstrip().split()]
    A[i+1].extend(line[2:])

d[1] = 0

q.put(1)
while not q.empty():
    v = q.get()
    if visited[v] == True:
        continue
    visited[v] = True
    for i in A[v]:
        if d[i] == -1:
            d[i] = d[v] + 1
        else:
            d[i] = min(d[i],d[v] + 1)
        q.put(i)
        
for i in range(n):
    print(str(i+1)+" "+str(d[i+1]))

Python: import queue

n = int(input())

Graph = [[x-1 for x in list(map(int, input().split()))[2:]] for i in range(n)]


# for i in range(n):
#     li = list(map(int, input().split()))
#     a = li[0]
#     a-=1
#     b = li[2:]
#     Graph[a].append(b)


dist = [-1]*n
q = queue.Queue()

dist[0] = 0
q.put(0)

while not q.empty():
    v = q.get()

    for nv in Graph[v]:
        if dist[nv] != -1: continue

        dist[nv] = dist[v] + 1
        q.put(nv)


for v in range(n):
    print(v+1, dist[v])

Python: INF = 10**18 + 7


def main():
    from collections import deque
    N = int(input())
    G = [[] for _ in range(N)]
    for _ in range(N):
        u, k, *A = (int(i)-1 for i in input().split())
        G[u] = A

    def bfs(s=0):
        que = deque([])
        dist = [INF]*N
        dist[s] = 0
        que.append(s)
        while que:
            pos = que.popleft()
            for v in G[pos]:
                if dist[v] != INF:
                    continue
                dist[v] = dist[pos] + 1
                que.append(v)
        return dist

    dist = bfs()
    for i, d in enumerate(dist, start=1):
        print(i, d if d != INF else -1)


if __name__ == '__main__':
    main()

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using Graph = vector<vector<int>>;

int main(){
    int n; cin>>n;
    Graph G(n);
    rep(i,n){
        int u,k; cin>>u>>k;
        rep(j,k){
            int v; cin>>v;
            G[u-1].push_back(v-1);
        }
    }

    vector<int> dist(n,-1);
    queue<int> que;

    dist[0]=0;
    que.push(0);

    while(!que.empty()){
        int v = que.front();
        que.pop();

        for(auto nv : G[v]){
            if(dist[nv]!=-1)continue;
            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }
    rep(i,n){
        cout<<i+1<<" "<<dist[i]<<endl;
    }
    return 0;
}

C++: #include <stdio.h>
#include <queue>
using namespace std;
struct bfs{
    int n;
    int l;
};
int main(){
    int n,a,m,temp,ans[101];
    bool graph[101][101];
    bfs t,b;
    queue<bfs> q;
    scanf("%d",&n);
    for(int i=0;i<101;i++){
        for(int j=0;j<101;j++){
            graph[i][j]=false;
        }
        ans[i]=-1;
    }
    for(int i=0;i<n;i++){
        scanf("%d%d",&a,&m);
        for(int j=0;j<m;j++){
            scanf("%d",&temp);
            graph[a][temp]=true;
        }
    }
    t.n=1;
    t.l=0;
    q.push(t);
    while(!q.empty()){
        t=q.front();
        q.pop();
        if(ans[t.n]==-1)ans[t.n]=t.l;
        else continue;
        t.l++;
        b=t;
        for(int i=1;i<=n;i++){
            if(graph[t.n][i]){
                b.n=i;
                q.push(b);
            }
        }
    }
    for(int i=1;i<=n;i++){
        printf("%d %d\n",i,ans[i]);
    }
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
#include <string.h>
#include <limits.h>
using namespace std;
vector<int> v[101];
int d[101];
queue<int> q;
bool flag[101];
int main(){
	int n, u, k; scanf("%d", &n);
	for (int i = 0; i < n; ++i){
		scanf("%d %d", &u, &k);
		for (int j = 0; j < k; ++j){
			int tmp; scanf("%d", &tmp);
			v[u].push_back(tmp);
		}
	}
	memset(d, -1, sizeof(d));
	d[1] = 0;
	q.push(1); flag[1] = true;
	while (!q.empty()){
		int m = q.front(); q.pop();
		for (int i = 0; i < v[m].size(); ++i){
			int tmp = v[m][i];
			if (!flag[tmp]){
				flag[tmp] = true;
				d[tmp]=d[m]+1;
				q.push(tmp);
			}
		}
	}
	for (int i = 1; i <= n; ++i){
		cout << i << ' ' << d[i] << '\n';
	}
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repr(i, n) for (int i = (n); i >= 0; --i)
#define FOR(i, m, n) for (int i = (m); i < (n); ++i)
#define FORR(i, m, n) for (int i = (m); i >= (n); --i)
using namespace std;
typedef long long ll;
const ll mod = 1000000007;
const ll mod2 = 998244353;
const int INF = 1000000005;
const int MAX = 105;

vector<int> to[MAX];
bool seen[MAX];
int d[MAX];

void bfs(int u) {
  queue<int> q;
  seen[u] = true;
  d[u] = 0;
  q.push(u);
  while (!q.empty()) {
    u = q.front();
    q.pop();
    for (int v: to[u]) {
      if (seen[v]) continue;
      d[v] = d[u] + 1;
      seen[v] = true;
      q.push(v);
    }
  }
}

int main() {
  int n, u, k, v;
  cin >> n;
  rep(i, n) {
    cin >> u >> k;
    rep(j, k) {
      cin >> v;
      to[u-1].push_back(v-1);
    }
  }

  rep(i, n) {
    seen[i] = false;
    d[i] = INF;
  }

  bfs(0);

  rep(i, n) {
    cout << i+1 << " ";
    if (seen[i]) cout << d[i] << endl;
    else cout << -1 << endl;
  }



  
  return 0;
}