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 <queue>
using namespace std;

int n;
char c[101];
int g[101][101];
int t = 0;
int visit[101];
int finish[101];
int d[101];
int dist = 0;

void bfs(int start) {
    t++;
    queue<int> q;
    q.push(start);
    c[start] = 'g';
    visit[start] = t;
    while(!q.empty()) {
        t ++;
        int now = q.front();
        dist ++;
        for (int i = 1; i <= n ; ++i) {
            if(g[now][i] && c[i] == 'w') {
                q.push(i);
                c[i] = 'g';
                visit[i] = t;
                d[i] = d[now] + 1;
            }
        }
        q.pop();
        c[now] = 'b';
        finish[now] = t;
    }
}
int main() {
    cin >> n;
    for (int i = 1; i <= n ; ++i) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; ++j) {
            int v;
            cin >> v;
            g[u][v] = 1;
        }
    }

    for (int l = 0; l < n; ++l) {
        c[l+1] = 'w';
    }

    for (int i1 = 1; i1 <=n ; ++i1) {
        d[i1] = -1;
    }
    for (int m = 1; m <= n ; ++m) {
        d[1] = 0;
        if(c[m] == 'w') bfs(m);
        break;

    }
    for (int j1 = 1; j1 <=n ; ++j1) {
        cout << j1 << " " << d[j1] << 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<queue>
using namespace std;
#define INF 9999999

int G[101][101];
int dis[101];
int main(){
  int n;
  cin>>n;
  for(int i=0;i<n;i++){
    int u,k;
    cin>>u>>k;
    for(int j=1;j<=k;j++){
      G[u][0]=k;
      cin>>G[u][j];
    }
  }
  fill(dis,dis+101,INF);
  dis[1]=0;
  queue<int> Q;
  Q.push(1);
  while(!Q.empty()){
    int num=Q.front(); Q.pop();
    for(int i=1;i<=G[num][0];i++){
      int k=G[num][i];
      dis[k]=min(dis[num]+1,dis[k]);
      Q.push(k);
    }
  }
  for(int i=1;i<=n;i++){
    cout<<i<<" "<<dis[i]<<"\n";
  }
}

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 (!p.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() {

  cin >> n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }

  int u, k, v;
  for (int i = 0; i < n; i++) {
    cin >> u >> k;
    u--; // to 0 origin
    for (int j = 0; j < n; j++) {
      cin >> v;
      v--; // to 0 origin
      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,100000000000);
	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]-1 << endl;
	
}

C++: //#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
using in = int64_t;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define REP(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
const double PI=3.14159265358979323846;
const in MOD = 1000000007;
const in INF=1<<30;
using P=pair<int,int>;
vector<int> dx={0,1,-1,0};
vector<int> dy={1,0,0,-1};

struct edge{int to; int cost;};
vector<vector<edge>> graph(0);
vector<int> d(0);
const int MAX_dist=1e9;

void init(int n){
    graph.resize(n);
    d.resize(n,MAX_dist);
}

void dijkstra(int s){
    priority_queue<P, vector<P>, greater<P>> que;
    d[s]=0;
    que.emplace(0,s);
    while(!que.empty()){
        P p=que.top();
        que.pop();
        int v=p.second;
        if(d[v]<p.first) continue;
        rep(i,graph[v].size()){
            edge e=graph[v][i];
            if(d[e.to]>d[v]+e.cost){
            d[e.to]=d[v]+e.cost;
            que.emplace(d[e.to],e.to);
            }
        }
    }
}

int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cout << fixed << setprecision(10);
    int n;cin>>n;
    init(n);
    int k,v;
    rep(i,n){
        cin>>k;cin>>k;
        rep(j,k){
            cin>>v;
            graph[i].push_back({v-1,1});
        }
    }
    dijkstra(0);
    rep(i,n){
        cout<<i+1<<" ";
        if(d[i]==MAX_dist) cout<<-1;
        else cout<<d[i];
        cout<<'\n';
    }
}

C++: #include<iostream>
#include<queue>
using namespace std;
int N;
int D[100];
void bfs(int src){
    int u[100],k[100],a[10001],d[100][100];
    bool visit[100];
    for(int i=1;i<=N;++i){
        cin>>u[i]>>k[i];
        for(int j=0;j<k[i];++j){
            cin>>a[j];
            d[u[i]][a[j]]=1;
        }
        visit[i]=true;
    }
    queue<int>Q;
    Q.push(src);
    D[src]=0;
    visit[src]=false;
    while(!Q.empty()){
        int cur=Q.front();
        Q.pop();
        for(int i=1;i<=N;++i){
            if(d[cur][i]==1&&visit[i]){
                visit[cur]=false;
                visit[i]=false;
                D[i]=D[cur]+1;
                Q.push(i);
            }
        }
    }
    for(int i=1;i<=N;++i){
        if(i!=1&&D[i]==0){
            D[i]=-1;
        }
        cout<<i<<" "<<D[i]<<endl;
    }
}
int main(){
    cin>>N;
    int start=1;
    bfs(start);
}