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++: //
// Created by ?????°?????? on 2016/05/15.
//

#include <iostream>
#include <queue>
using namespace std;
const int N = 100;
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,v,k;
    for (int i = 0; i < n ; ++i) {
        for (int j = 0; j < n ; ++j) {
            M[i][j] = 0;
        }
    }
    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 inf 1<<30

int n,M[105][105],d[105];
queue<int> Q;

void dfs(int s){
	d[s]=0;
	Q.push(s);
	int v;
	while(!Q.empty()){
		s=Q.front();Q.pop();
		for(int v=0;v<n;v++){
			if(M[s][v]==0){
				continue;
			}
			if(d[v]!=-1){
				continue;
			}
			d[v]=d[s]+1;
			Q.push(v);
		}
	}
}

int main() {
  cin>>n;
  for(int i=0;i<105;i++){
  	d[i]=-1;
    for(int j=0;j<105;j++){
      M[i][j];
    }
  }
  int u,k,v;
  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);
  for(int i=0;i<n;i++){
  	printf("%d %d\n",i+1,d[i]);
  }
}

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

#define N 100
#define 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() {
  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++ ) {
    int a, b;
    cin >> a >> b;
    --a;
    for ( int j = 0; j < b; j++ ) {
      int c;
      cin >> c;
      M[a][--c] = 1;
    }
  }

  bfs(0);

  return 0;
}

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

std::queue<std::pair<int, int>> q;
std::vector<std::vector<int>> vec;
std::vector<int> distances;
int n, id, num, d;

void bfs_search(int start_id) {
    q.push(std::make_pair(start_id, 0));
    while (!q.empty()) {
        auto x = q.front();
        q.pop();
        distances[x.first-1] = x.second;
        for (int i = 1; i <= n; i++) {
            if (vec[x.first][i] == 1 && distances[i-1] == -1) {
                q.push(std::make_pair(i, x.second+1));
                distances[i-1] = x.second;
            }
        }
    }
}

int main() {
    std::cin >> n;
    vec.assign(n+1, std::vector<int>(n+1, -1));
    for (int i = 0; i < n; ++i) {
        std::cin >> id >> num;
        for (int p = 0; p < num; p++) {
            std::cin >> d;
            vec[id][d] = 1;
        }
    }
    for (int i = 0; i < n; i++) {
        distances.push_back(-1);
    }
    bfs_search(1);
    for (int i = 0; i < n; i++) {
        std::cout << i+1 << " " << distances[i] << std::endl;
    }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>

using namespace std;

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

static const int N = 100;
static const int FAR = (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] = FAR;
	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] != FAR) continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	for (int i = 0; i < n; ++i)
		cout << i + 1 << " " << ((d[i] == FAR) ? -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;
	}

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

	bfs(0);

	return 0;
}

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

#define REP(i, n) for(int i = 0; i < n; i++)
using namespace std;

int main()
{   
    /* 座席　（中央×後）*/
    //資料の説明通りにやってみたつもりです

    int n;
    cin >> n;
    vector<vector<int>> edges(n, vector<int>());

    REP(i, n) {
        int u, k, e;
        cin >> u >> k;

        REP(j, k) {
            cin >> e;
            edges.at(u-1).push_back(e-1);
        }
    }

    queue<int> Q;
    vector<int> dst(n, 1000000);

    dst[0] = 0;
    Q.push(0);

    while (!Q.empty()) {
        int cur = Q.front();
        Q.pop();

        REP(i, edges[cur].size()) {
            if (dst[edges[cur][i]] == 1000000)
                Q.push(edges[cur][i]);
                if (dst[edges[cur][i]] > dst[cur]+1)
                    dst[edges[cur][i]] = dst[cur]+1;
        }
    }

    REP(i, n) {
        if (dst[i] == 1000000)
            cout << i+1 << " " << -1 << endl;
        else 
            cout << i+1 << " " << dst[i] << endl;
    }
}

C++: #include <iostream>
#include <queue>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;
int m[N][N],color[N],d[N],n;



void bfs(int s){
	
	queue<int> q;
	q.push(s);
	for(int i=0;i<N;i++){
		color[i] = WHITE;
		d[i] = (1<<21);
	}
	d[s] = 0;
	color[s] = GRAY;
	int u;
	while(!q.empty()){
		u = q.front();
		q.pop();
		
		for(int v=0;v<n;v++){
			if(m[u][v]&&color[v]==WHITE){
				color[v] = GRAY;
				d[v] = d[u]+1;
				q.push(v);
			}
		}
	}
	for(int i=0;i<n;i++){
			cout<<i+1<<" "<<((d[i]==(1<<21))?(-1):(d[i]))<<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--;
				m[u][v]=1;
			}
		}
		bfs(0);
		
		return 0;
}