Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

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

C++: #include<bits/stdc++.h>
using namespace std;

typedef long long ll;

int main()
{
    ll i,j;
    ll n;
    cin >> n;
    vector<vector<ll>> graph(n);
    for(i = 0;i < n;++i){
        ll u,k,v;
        cin >> u >> k;
        --u;
        for(j = 0;j < k;++j){
            cin >> v;
            --v;
            graph.at(u).push_back(v);
        }
    }
    queue<ll> que;
    vector<ll> visit(n,false);
    que.push(0);
    visit.at(0) = true;
    vector<ll> ans(n,-1);
    ans.at(0) = 0;
    while(!que.empty()){
        ll s = que.front();
        que.pop();
        ll dis = ans.at(s);
        for(i = 0;i < graph.at(s).size();++i){
            ll g = graph.at(s).at(i);
            if(visit.at(g)){
                continue;
            }
            ans.at(g) = dis+1;
            visit.at(g) = true;
            que.push(g);
        }
    }
    for(i = 0;i < n;++i){
        cout << i+1  << " " << ans.at(i) << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <queue>

using namespace std;
static const int N = 100;
static const int INFTY = (1<<21);

int n, M[N][N];
int d[N];

void bfs(int s) {
    queue<int> q;
    q.push(s);
    for(int i=0; i<n; i++) d[i] = INFTY;
    d[s] = 0;
    int u;
    while(!q.empty()) {
        u = q.front(); q.pop();
        for(int v=0; v<n; v++) {
            if(M[u][v] == 0) continue;
            if(d[v] != INFTY) continue;
            d[v] = d[u] + 1;
            q.push(v);
        }
    }
    for(int i=0; i<n; i++) {
        cout << i+1 << " " << ((d[i] == INFTY) ? (-1) : d[i]) << endl;
    }
}

int main() {
    int u, k, v;
    
    cin >> n;
    for(int i=0; i<n; i++) {
        for(int j=0; j<n; j++) M[i][j] = 0;
    }
    
    for(int i=0; i<n; i++) {
        cin >> u >> k;
        u--;
        for(int j=0; j<k; j++) {
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
    
    bfs(0);
    
    return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
#include<algorithm>

using namespace std;

int main() {
	int n, u, k, v;
	cin >> n;
	vector<int> ans(n,1000000000);
	vector<vector<int>> adj(n);
	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		while (k--)cin >> v, adj[u-1].push_back(v-1);
	}
	queue<pair<int, int>> q;//<idx,path>
	q.push(pair<int, int>(0, 1));
	while (!q.empty()) {
		auto tmp = q.front(); q.pop();
		ans[tmp.first] = min(ans[tmp.first], tmp.second);
		for (int i = 0; i < adj[tmp.first].size(); i++) q.push(pair<int, int>(adj[tmp.first][i], tmp.second+1));
	}
	for (int i = 0; i < n; i++)	cout << i + 1 << " " << (ans[i] == 1000000000 ? -1 : ans[i]-1) << endl;
	
}

C++: #include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>

#include <iostream>
#include <complex>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>

#include <functional>
#include <cassert>

typedef long long ll;
using namespace std;

#define debug(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl;

#define mod 1000000007 //1e9+7(prime number)
#define INF 1000000000 //1e9
#define LLINF 2000000000000000000LL //2e18
#define SIZE 100010


int main(){
  int n;
  bool connected[200][200] = {};
  
  scanf("%d", &n);

  for(int i=0;i<n;i++){
    int u, k, v;

    scanf("%d%d", &u, &k);
    u--;
    
    for(int j=0;j<k;j++){
      scanf("%d", &v);
      v--;

      connected[u][v] = true;
    }
  }

  queue<int> q1, q2;
  bool visited[200] = {};
  int ans[200];

  for(int i=0;i<n;i++) ans[i] = -1;
  
  q1.push(0);

  for(int i=0;q1.size();i++){

    while(q1.size()){
      int p = q1.front();
      q1.pop();

      if(visited[p]) continue;
      visited[p] = true;

      ans[p] = i;
      
      for(int j=0;j<n;j++){
        if(connected[p][j]){
          q2.push(j);
        }
      }
    }

    q1 = q2;
    q2 = queue<int>();
  }

  for(int i=0;i<n;i++)
    printf("%d\n", ans[i]);
  
  return 0;
}