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>
#include <cstring>
using namespace std;

struct edge{
    int node;
    edge *next;
}nodes[105];

int n,d[105],v[105];
queue<edge> E;

void bfs(){
    edge *e=E.front().next;
    while(e!=NULL){
        int num=e->node;
        if(v[num]==0){
            v[num]=1;
            d[num]=d[E.front().node]+1;
            E.push(nodes[num]);
        }
        e=e->next;
    }
    E.pop();
}

int main(){
    memset(v,0,sizeof(v));
    memset(d,-1,sizeof(d));
    cin>>n;
    int i,j;
    for(i=1;i<=n;i++){
        int ii,n_i;
        cin>>ii>>n_i;
        nodes[ii].node=ii;
        edge *first=&nodes[ii];
        for(j=0;j<n_i;j++){
            edge *e=new edge();
            cin>>e->node;
            first->next=e;
            first=e;
        }
    }
    d[1]=0;
    E.push(nodes[1]);
    while(E.size()!=0){
        bfs();
    }
    for(i=1;i<=n;i++)cout<<i<<" "<<d[i]<<endl;
    return 0;
}

C++: #include<iostream>
#include<queue>
#include<vector>
using namespace std;
vector<vector<int>> G(100);
vector<int> d(100);
const int INF = 1<<28;
void bfs(){
    queue<int> Q;
    Q.push(0);
    fill(d.begin(),d.end(),INF);
    d[0]=0;
    while(!Q.empty()){
        int u=Q.front();
        Q.pop();
        for(auto a:G[u]){
            if(d[a]!=INF) continue;
            d[a]=d[u]+1;
            Q.push(a);
        }
    }
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin>>n;
    for(int i=0;i<n;++i){
        int u,k;
        cin>>u>>k;
        for(int j=0;j<k;++j){
            int v;
            cin>>v;
            G[u-1].push_back(v-1);
        }
    }
    bfs();
    for(int i=0;i<n;++i)
        cout<<i+1<<' '<<d[i]<<endl;
}

C++: #include<iostream>
#include<queue>
#include<utility>
#define F first
#define S second
using namespace std;
typedef pair< int, int >p;//first = node , second = time

bool g[101][101];
int t[101];

main()
{
  int n, u, k, v;
  queue<p>que;

  cin >> n;

  for ( int i = 0; i < n ; ++i) {
    t[i] = -1;
    for(int j = 0; j < n ; ++j) {
      g[i][j] = false;
    }
  }
  
  for (int i = 0; i < n ; ++i) {
    cin >> u >> k; --u;
    
    for (int j = 0; j < k ; ++j) {
      cin >> v; --v;
      g[u][v] = true;
    }
  }

  que.push(p(0,0));
  t[0] = 0;
  while ( !que.empty() ) {
    p now = que.front(); que.pop();
    
    int pos = now.F;
    int time = now.S;
    
    for ( int i = 0; i < n ; ++i) {
      if ( g[pos][i] && t[i] == -1 ) {
	t[i] = time + 1;
	que.push(p(i,time+1));
      }
    }
  }

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

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

int main(){
  int n;
  vector<int> mat[100];
  cin >> n;
  for(int i=0;i<n;i++){
    int u,k;
    cin >> u >> k;
    for(int j=0;j<k;j++){
      int v;
      cin >> v;
      mat[i].push_back(v);
    }
  }

  int d[100];
  for(int i=0;i<n;i++) d[i]=(-1);

  queue<int> nb;
  nb.push(0);
  d[0]=0;

  while(!nb.empty()){
    for(vector<int>::iterator it=mat[nb.front()].begin();it!=mat[nb.front()].end();it++){
      if(d[*it]==-1){
        d[*it]=d[nb.front()]+1;
        nb.push(*it);
      }
    }
    nb.pop();
  }

  for(int i=1;i<=n;i++)
    cout << i << ' ' << d[i-1] << endl;
  
  return 0;
}

C++: /*
?????????: Graph I - Breadth First Search
URL: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_C
?????°
19:08 ??°?????????????????????????????£??¨??????????????????????????§???????????????????????£?????????
19:08 ???????????\????????\????????°??????????????????????¢????
19:09 ????????°???????????????????§£
19:13 ??¨???????????????????????£???
19:19 BFS????¨???¶???????¶??????????????????§??¨?????????????????????????????????
19:28 ???????????????????§?????????????????????£????????§????????????????????????????????????????????§????????????????????£????????????
*/
#include <iostream>
#include <vector>
#include <set>
#include <queue>
#define INF 114514
using namespace std;

int main()
{
	int n; cin>>n;
	vector< set<int> > graphdat(n+1);  
	for(int i=0;i<n;i++){
		int u; int k; cin >> u >> k;
		set<int> v;
		for(int j=0;j<k;j++){
			int tmp;
			cin >> tmp;
			v.insert(tmp);
		}
		graphdat[u] = v;
	}

	vector<int> distance(n+1);
	distance[1] = 0;
	for(int i=2;i<=n;i++){
		distance[i] = INF;
	}

	queue<int> Q;
	Q.push(1);

	while(!Q.empty()) {
		int cur = Q.front();
		Q.pop(); // pop?????????????????????????????¨?¬???\??§??????
		for(int dest=1; dest<=n; dest++) {
			if(graphdat[cur].find(dest) != graphdat[cur].end()) { // ??????????????????
				if(distance[dest] > distance[cur] + 1) { // ??´??°??§????????????
					distance[dest] = distance[cur] + 1;
					Q.push(dest);
				}
			}
		}
	}

	for(int i=1;i<=n;i++){
		cout << i << " " << distance[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);

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;
}

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;
    }
}

C++: #include<stdio.h>


#define MAX 101
#define WHITE 2
#define GRAY 1
#define BLACK 0

int col[MAX], d[MAX], a[MAX][MAX]; 
 
int n, h= 0, t = 0;


int Que[MAX];


/*Qの操作*/
 int Dequeque(){
  h++;
  return Que[h - 1];
}
void Enqueque(int b){
  Que[t] = b;
  t++;
}

 
void BFS(int s){
  int i, u;
  for(i = 1; i < n+1; i++){
      col[i] = WHITE;


      d[i] = -1;
  }
  d[s] = 0;
  

  col[s] = GRAY;
  
  Enqueque(s);
 
  while(h != t){
    u = Dequeque();
    for(i = 1; i <= n; i++){
      if((col[i] == WHITE) && (a[u][i] == 1)){


    col[i] = GRAY;
    d[i] = d[u] + 1;
    Enqueque(i);
      }
    }
   

    col[u] = BLACK;
  }
}
 

  
int main(){
 
  scanf("%d", &n);
 
  int i, u, j,y=1,e;



  /*配列の初期化*/
  for(i = 1; i < n+1; i++){
    for(j = 1; j < n+1; j++){
     

 a[i][j] = 0;

    }
  }

  int x; 
  for(i = 1; i < n+1; i++){

    scanf("%d%d",&u,&e);
    for(j = 1; j <= e; j++){
      scanf("%d", &x);
      a[i][x] = 1;
    }
  }
 
  BFS(y);
   
  for(i = 1; i < n+1; i++){
    printf("%d ", i);
    printf("%d\n", d[i]);
  }
  return 0;
}