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 <iostream>
#include <vector>
#include <queue>

using namespace std;

int main()
{
  bool firstFlag = true;
  int N, u, k, v, frontNum, ansNum;
  int depth = 0;

  cin >> N;
  vector<vector<int> > G(N, vector<int>(N, 0));
  vector<int> ansList(N, -1);
  queue<int> q, r;

  for (int i = 0; i < N; i++){
    cin >> u >> k;
    for (int j = 0; j < k; j++){
      cin >> v;
      G[u - 1][v - 1] = 1;
    }
  }
  q.push(0);
  ansList[0] = 0;
  while(!q.empty()){
    frontNum = q.front();
    q.pop();
    for (int i = 0; i < N;i++){
      if(G[frontNum][i] == 0)continue;
      if(ansList[i] != -1)continue;
      ansList[i] = ansList[frontNum] + 1;
      q.push(i);
    }
  }
  for (int i = 0; i < ansList.size();i++){
    cout << i + 1 << " " << ansList[i] << endl;
  }
  return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
static const int N=100;
static const int INFTY =(1<<21);

int n,M[N][N];
int d[N];//?????¢??§?¨??????¶???(color)???????????????

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 <stack>
#define NIL -1
#define N 110

using namespace std;

bool A[N + 1][N + 1];
int d[N + 1];
int n;

stack<int> s1;
stack<int> s2;

void bfs(int depth, stack<int> si, stack<int> so) {
  if (si.empty()) return;
  while (!si.empty()) {
    int u = si.top();
    si.pop();
    for (int v = 1; v <= n; v++) {
      if (A[u][v] && d[v] == NIL) {
        so.push(v);
        d[v] = depth;
      }
    }
  }
  bfs(depth + 1, so, si);
}

int main() {

  cin >> n;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      A[i][j] = false;
    }
  }

  for (int i = 1; i <= n; i++) {
    int u, k, v;
    cin >> u >> k;
    for (int j = 1; j <= k; j++) {
      cin >> v;
      A[u][v] = true;
    }
  }

  for (int i = 1; i <= N; i++) d[i] = NIL;
  s1.push(1);
  d[1] = 0;
  bfs(1, s1, s2);

  for (int i = 1; i <= n; i++) {
    cout << i << " " << d[i] << endl;
  }
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n) ; i++)
constexpr auto INF = 2147483647;
typedef long long ll;

int main(){

  int n;
  cin >> n;
  int score[101];
  bool adjacent_graph[101][101];
  rep(i,101){
    score[i] = -1;
    rep(j,101) adjacent_graph[i][j] = false;
    }

  int vertex,edge,direction;
  rep(i,n){
    cin >> vertex >> edge;
    rep(j,edge){
      cin >> direction;
      adjacent_graph[vertex][direction]  = true;
      // adjacent_graph[direction][vertex]  = true;
    }
  }
  queue<int> que;
  que.push(1);
  score[1] = 0;
  while(!que.empty()){
    int now = que.front();que.pop();
    rep(i,n+1) {
      if(adjacent_graph[now][i] && score[i] == -1){
        score[i] = score[now]+1;
        que.emplace(i);
      }
    }
  }

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

  return 0;
}

C++: #include<iostream>
#include<queue>
using namespace std;
const int MAXN = 105;
const int INF = 1<<21;
int a[105][105];
int d[MAXN];
int n;


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

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

C++: #include<bits/stdc++.h>
using namespace std;
static const int INF=1000000;

int main(){
  int n,u,k,v;
  cin>>n;
  vector<int> G[n];
  int D[n];
  
  for(int i=0;i<n;i++){
    cin>>u>>k;
    u--;
    for(int j=0;j<k;j++){
      cin>>v;
      v--;
      G[u].push_back(v);
      //cout<<"#"<<u<<v<<endl;
      //G[v].push_back(u);
    }
  }
  for(int i=0;i<n;i++){
    D[i]=INF;
  }
    
  D[0]=0;
  queue<int>Q;
  Q.push(0);
  while(!Q.empty()){
    int u=Q.front();Q.pop();
    for(int i=0;i<G[u].size();i++){
      v=G[u][i];
      if(D[v]!=INF) continue;
      D[v]=D[u]+1;
      Q.push(v);
    }
  }
  for(int i=0;i<n;i++){
    cout<<i+1<<" "<<(D[i]==INF ? -1:D[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++ ){
        cin >> u >> k;
        u--;
        for ( int j = 0; j < k; j++ ){
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
    bfs(0);
    
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define MAX 105

vector<vector<int> > vec;
vector<int> ve;
int dis[MAX];
queue<int> Q;
int n;

int search(int start, int end) {
	while(!Q.empty()) Q.pop();
	Q.push(start);
	for (int i = 1; i <= n; i++) {
		dis[i] = 0;
	}
	int now, len = 0;
	while (!Q.empty()) {
		now = Q.front();
		Q.pop();
		if (now == end)
			return dis[now];
		if (dis[now] == len)
			len++;
		for (int cnt = 1; cnt <= vec[now][0]; cnt++) {
			if (dis[vec[now][cnt]] == 0) {
				dis[vec[now][cnt]] = len;
				Q.push(vec[now][cnt]);
			}
		}
	}
	return -1;
}

int main(void) {
	vec.push_back(ve);
	int u, k, v, i;
	cin >> n;
	for (i = 1; i <= n; i++) {
		ve.clear();
		cin >> u >> k;
		ve.push_back(k);
		while (k--) {
			cin >> v;
			ve.push_back(v);
		}
		vec.push_back(ve);
	}

	for (i = 1; i <= n; i++) {
		cout << i << " " << search(1, i) << endl;
	}
	
}