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 <iostream>
#include <queue>
 
using namespace std;
 
int D[110]={0};
void bfs(int src,int n,int g[110][110]){
 
queue<int> Q;
Q.push(src);
D[src]=0;
while (! Q.empty()){
    int cur =Q.front();
    Q.pop();
    for(int r=0;r<n;r++){
        if (g[cur][r]==1&&D[r]==0){
            D[r]=D[cur]+1;
            Q.push(r);
        }
    }
}
}
int main() {
int n,g[110][110]={0};
cin>>n;
int j,num,t;
for(int k=0;k<n;k++){
cin>>j>>num;
for(int kk=0;kk<num;kk++){
    cin>>t;
    g[k][t-1]=1;
}
}
bfs(0,n,g);

for(int a=0;a<n;a++){
	if(a!=0){
    if(D[a]!=0){
    cout<<a+1<<" "<<D[a]<<endl;
}
else{
		cout<<a+1<<" -1"<<endl;
}
}
else{
	cout<<a+1<<" 0"<<endl;
}

}
    return 0;
}

C++: #include<iosrteam>
#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;
    }
  }

  dfs(0);

  return 0;
}

C++: #include <queue>
#include <vector>
#include <iostream>
using namespace std;

// ------ Class ------ //
class Graph1 {
public:
	// ------ Variables ------ //
	static const int INF = 1000000000;
	int V, E; vector<vector<int> > G;

	// ------ Constructors ------ //
	Graph1() : V(0), E(0), G(vector<vector<int> >()) {}
	Graph1(int v) : V(v), E(0), G(vector<vector<int> >(v)) {}
	Graph1(vector<vector<int> > g) : V(g.size()), G(g) { for (int i = 0; i < g.size(); i++) E += g[i].size(); }

	// ------ Basic Functions ------ //
	int size() { return V; }
	void add1(int v1, int v2) { G[v1].push_back(v2); E++; }
	void add2(int v1, int v2) { add1(v1, v2); add1(v2, v1); }

	// ------ Operators ------ //
	friend bool operator==(const Graph1& g1, const Graph1& g2) { return g1.G == g2.G; }
	friend bool operator!=(const Graph1& g1, const Graph1& g2) { return g1.G != g2.G; }
	vector<int> operator[](int x) { return G[x]; }

	// ------ Algorithms ------ //
	vector<int> dist(int s) {
		queue<int> que; que.push(s);
		vector<int> d(V, INF); d[s] = 0;
		while (!que.empty()) {
			int u = que.front(); que.pop();
			for (int i = 0; i < G[u].size(); i++) {
				if (d[G[u][i]] == INF) {
					d[G[u][i]] = d[u] + 1;
					que.push(G[u][i]);
				}
			}
		}
		return d;
	}
};

// ------ Main ------ //
int n, u, k, v;
int main() {
	cin >> n; Graph1 g(n);
	for(int i = 0; i < n; i++) {
		cin >> u >> k;
		for(int j = 0; j < k; j++) cin >> v, g.add1(u - 1, v - 1);
	}
	vector<int> d = g.dist(0);
	for(int i = 0; i < n; i++) cout << i + 1 << ' ' << (d[i] != Graph1::INF ? d[i] : -1) << endl;
}

C++: #include <bits/stdc++.h>
#define ALL(a)  (a).begin(),(a).end()
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
typedef pair<long long, long long> Pll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<long long> vll;
typedef vector<vector<long long>> vvll;
template <typename T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template <typename T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const long long INF = 1LL << 60;


int main(){
  int n;
  cin >> n;
  vvll edge(n, vll(0));
  for(int i = 0; i < n; i++){
    ll u, k;
    cin >> u >> k;
    u--;
    for(int j = 0; j < k; j++){
      ll v;
      cin >> v;
      v--;
      edge.at(u).push_back(v);
    }
  }

  vector<Pll> d(n);
  for(int i = 0; i < n; i++){
    d.at(i).first = INF;
    d.at(i).second = (ll)i;
  }
  d.at(0).first = 0;

  priority_queue<P, vector<P>, greater<P>> que;
  que.push(make_pair(0,0));

  while(!que.empty()){
    P p = que.top(); que.pop();

    if(d.at(p.second).first < p.first) continue;

    for(int i = 0; i < edge.at(p.second).size(); i++){
      ll v = edge.at(p.second).at(i);
      if(d.at(v).first > p.first + 1LL){
        d.at(v).first = p.first + 1LL;
        que.push(d.at(v));
      }  
    }
  }

  for(int i = 0; i < n; i++){
    if(i == 0) continue;
    if(d.at(i).first == INF) d.at(i).first = -1;
  }

  for(int i = 0; i < n; i++){
    cout << i+1 << ' ' << d.at(i).first << endl;
  }

}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define REP(i,n) for(int i=1;i<=n;i++)
typedef long long ll;

int main(){
	int n;
	cin >> n;
	vector<vector<int> > to(n);
	rep(i,n){
		int u;
		cin >> u;
		u--;
		int k;
		cin >> k;
		rep(j,k){
			int v;
			cin >> v;
			v--;
			to[u].push_back(v);
		}
	}
	
	int dist[105];
	rep(i,n){
		dist[i] = -1;
	}
	
	queue<int> que;
	dist[0] = 0;
	que.push(0);
	while(!que.empty()){
		int p = que.front();
		que.pop();
		for (int i = 0; i < to[p].size(); ++i) {
			int nextv = to[p][i];
			if(dist[nextv] != -1) continue;
			dist[nextv] = dist[p] + 1;
			que.push(nextv);
		}
	}
	
	rep(i,n){
		cout << i+1 << " " << dist[i] << endl;
	}
    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;

int n, d[110];
bool a[110][110] = {};

void bfs(int u){
  
  queue<int> Q;
  
  Q.push(u);
  d[u] = 0;
  
  while(Q.size()){
    int p = Q.front();
    Q.pop();
    
    for(int i = 2;i <= n;i++){
      if(a[p][i] && d[i] == 0){
        Q.push(i);
        d[i] = d[p] + 1;
      }
    }
  }
}

int main(){
  
  int u, k, v;
  
  cin >> n;
  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> v;
      a[u][v] = true;
    }
  }
  
  bfs(1);
  
  for(int i = 1;i <= n;i++){
    if(d[i] || i == 1) cout << i << " " << d[i] << endl;
    else cout << i << " " << -1 << endl;
  }
  
  return 0;
}