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
}

C++: #include <bits/stdc++.h>
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
template<class T> inline bool chmax(T &a, T b) { if (a<b) {a=b; return 1;} return 0;}
template<class T> inline bool chmin(T &a, T b) { if (b<a) {a=b; return 1;} return 0;}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n;
    cin >> n;
    vector<vector<int>> to(n);
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        u--;
        rep(j, k) {
            int v;
            cin >> v;
            to[u].push_back(--v);
        }
    }

    queue<int> q;
    vector<int> dist(n, -1);
    q.push(0);
    dist[0] = 0;
    
    while (!q.empty()) {
        int v = q.front();
        q.pop();
        for (int i = 0; i < to[v].size(); ++i) {
            int nv = to[v][i];
            if (dist[nv] >= 0) continue;
            q.push(nv);
            dist[nv] = dist[v] + 1;
        }
    }

    rep(i, n) cout << i+1 << " " << dist[i] << endl;
}

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 <algorithm>
#include <map>
#include <vector>
#include <string>
#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<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 <algorithm>
#include <deque>
#include <iostream>
#include <map>
#include <sstream>
#include <vector>

using namespace std;

deque<int> to_visit;
int t = 1;

int main() {
  int n;
  cin >> n;

  vector<bool> visited(n + 1, false);
  vector<int> dist(n + 1, -1);
  vector<vector<int>> V(n + 1);

  cin.ignore();

  for (string line; getline(cin, line);) {
    istringstream is{line};
    int id, n_nbrs, nbr;
    is >> id >> n_nbrs;
    vector<int> out_nbrs;
    while (is >> nbr)
      out_nbrs.push_back(nbr);
    V[id] = out_nbrs;
  }

  to_visit.push_back(1);
  dist[1] = 0;
  while (!to_visit.empty()) {
    if (visited[to_visit.front()]) {
      to_visit.pop_front();
      continue;
    }
    int curr = to_visit.front();
    to_visit.pop_front();
    visited[curr] = true;
    for (auto nbr : V[curr]) {
      if (dist[nbr] == -1)
        dist[nbr] = dist[curr] + 1;
      to_visit.push_back(nbr);
    }
  }

  for (int i = 1; i < V.size(); ++i) {
    cout << i << " " << dist[i] << endl;
  }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <stdio.h>
#include <cmath>
#include <map>
#include <queue>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
  int n;
  cin >> n;
  vector<vector<int>> Garph(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    rep(j, k) {
      int v;
      cin >> v;
      Garph[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 next_v : Garph[v]) {
      if(dist[next_v] != -1) { continue;}
      dist[next_v] = dist[v] + 1;
      que.push(next_v);
    }
  }
  for(int i = 0; i < n; i++) {
    printf("%d %d\n", i+1, dist[i]);
  }
  return 0;
}