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>
using namespace std;
typedef long long LL;
const int INF = 0x3f3f3f3f;
const int MAXN = 100;
struct Graph{
    struct Edge{
        int to, w;
        Edge(int v, int _w):to(v), w(_w){}
    };
    vector<Edge> edge;
    vector<vector<int> > vertex;
    int V, E;
    Graph(int _V):V(_V),E(0){
        edge.clear(); vertex.clear();
        vertex.resize(V);
    }
    void addEdge(int u, int v, int w){
        vertex[u].push_back(E++);
        edge.push_back(Edge(v, w));
    }
};
void SPFA(Graph& G, LL* d, int s){
    bool inq[MAXN]; int cnt[MAXN];
    memset(cnt, 0, sizeof(int)*G.V);
    memset(d, INF, sizeof(LL)*G.V);
    memset(inq, false, sizeof(bool)*G.V);
    d[s] = 0; inq[s] = true;
    queue<int> q; q.push(s);
    while (q.size()){
        int p = q.front(); q.pop(); inq[p] = false;
        cnt[p]++; if (cnt[p] > G.V){ d[s] = -1; break;}
        for (auto index : G.vertex[p]){
            auto &e = G.edge[index];
            if (d[p] + e.w < d[e.to]){
                d[e.to] = d[p] + e.w;
                if (!inq[e.to]) inq[e.to] = true, q.push(e.to);
            }
        }
    }
}
int main(){
    int n;
    cin >> n;
    Graph G(n);
    LL d[MAXN];
    for (int i = 0 ; i < n ; i++){
        int m;
        cin >> m >> m;
        while (m--){
            int v;
            cin >> v;
            G.addEdge(i, v-1, 1);
        }
    }
    SPFA(G, d, 0);
    for (int i = 0 ; i < n ; i++)
        cout << i+1 << ' ' << d[i] << '\n';
}

C++: #include<bits/stdc++.h>

using namespace std;
int V;
vector<int> G[102];
bool vis[102];
int d[102];
const int inf=0x3f3f3f;

void bfs(int s=1){
    d[s]=0;
    queue<int> que;
    que.push(s);
    while(!que.empty()){
        int t=que.front();
        que.pop();
        vis[t]=true;
        for(int i=0;i<G[t].size();i++){
            if(!vis[G[t][i]]){
                que.push(G[t][i]);
                d[G[t][i]]=min(d[G[t][i]],d[t]+1);
            }
        }
    }
}


int main(){
    cin>>V;
	int i;
	for(int i=1;i<=V;i++){
        d[i]=inf;
        vis[i]=false;
	}
    for(i=1;i<=V;i++){
        int id,k;
        cin>>id>>k;
        while(k--){
            int out;
            cin>>out;
            G[id].push_back(out);
        }
        sort(G[id].begin(),G[id].end());
    }
    bfs();
    for(int i=1;i<=V;i++){
        cout<<i<<" "<<(d[i]==inf?-1:d[i])<<endl;
    }
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;

int main() {
  ll n;
  cin >> n;
  vector<set<ll>> v(n);
  for(ll i=0;i<n;i++) {
    ll f,k;
    cin >> f >> k;
    for(ll j=0;j<k;j++) {
      ll temp;
      cin >> temp;
      temp--;
      v[i].insert(temp);
    }
  }
  vector<ll> ans(n,-1);
  ans[0]=0;
  queue<ll> q;
  q.push(0);
  while(q.size()) {
    ll p=q.front();
    q.pop();
    for(ll t:v[p]) {
      if(ans[t]<0) {
        ans[t]=ans[p]+1;
        q.push(t);
      }
    }
  }
  for(ll i=0;i<n;i++) {
    cout << i+1 << " " << ans[i] << endl;
  }
}

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

using namespace std;

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

    vector<vector<int>> graph(n);

    for(int i = 0; i < n; i++ ){
        int v, k;
        cin >> v >> k;
        for(int j = 0; j < k; j++){
            int v2;
            cin >> v2;
            graph[v-1].push_back(v2-1);
        }
    }

    vector<int> d(n, -1);
    queue<int> q;
    q.push(0);
    d[0] = 0;

    while(!q.empty()){
        int cur = q.front();
        q.pop();
        for(int i = 0; i < graph[cur].size(); i++ ){
            int next = graph[cur][i];
            if(d[next] == -1){
                d[next] = d[cur]+1;
                q.push(next);
            }
        }
    }

    for(int i = 0 ; i < n; i++ ){
        cout << i+1 << " " << d[i] << endl;
    }

    return 0;
}

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

using namespace std;

static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
static const int INF = 1 << 30;

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


void dfs(int s){
    queue<int> q;
    q.push(s);
    for (int i = 0; i < n; ++i){
        d[i] = INF;
    }
    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] != 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;
    }
}

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;
        for (int j = 0; j < k; ++j){
            cin >> v;
            M[u - 1][v - 1] = 1;
        }
    }

    dfs(0);

    return 0;
}

C++: #include <iostream>
#include <string>
#include <map>
#include <queue>
#include <algorithm>
using namespace std;
#define MAX 100000

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]==1){
        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;
}