Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve
const INFTY = (1 << 21)
const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 頂点1から頂点iまでの距離
var color, d [MAX]int

func bfs(s int) {
	var q []int
	q = append(q, s)
	for i := 0; i < n; i++ {
		d[i] = INFTY
	}
	//sは開始点なので、0をいれる
	d[s] = 0

	//キューが空になるまで、以下を繰り返す
	for len(q) > 0 {
		u := q[0]
		q = q[1:]
		for v := 0; v < n; v++ {
			if M[u][v] == 0 {
				continue
			}
			if d[v] != INFTY {
				continue
			}
			d[v] = d[u] + 1
			q = append(q, v)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Printf("%d ", i+1)
		if d[i] == INFTY {
			fmt.Printf("%d\n", -1)
		} else {
			fmt.Printf("%d\n", d[i])
		}
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	bfs(0)

}

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

using namespace std;
#define INT_MIN     (-2147483647 - 1) /* minimum (signed) int value */
#define INT_MAX       2147483647    /* maximum (signed) int value */


static const int N = 100;
static const int NEW = 0;
static const int VISITING = 1;
static const int OLD = 2;

int n, m[N][N] = {0}, t;
int color[N] = { 0 }, t1[N] = { 0 }, t2[N] = {0};

void getMatrix()
{
	int u, v, k;
	cin >> n;
	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;
		}
	}
}

int nxt(int idx)
{
	for (int i = 0; i < n; ++i)
	{
		if (1 == m[idx][i] && color[i] == NEW)
			return i;
	}
	return -1;
}

void dfs_visit(int idx)
{
	stack<int> s;
	s.push(idx);
	color[idx] = VISITING;
	t1[idx] = t++;


	while (!s.empty())
	{
		int u = s.top();
		int v = nxt(u);
		if (-1 != v)
		{
			color[v] = VISITING;
			t1[v] = t++;
			s.push(v);
		}
		else
		{
			s.pop();
			color[u] = OLD;
			t2[u] = t++;
		}
	}
}

void dfs()
{
	t = 1;

	for (int i = 0; i < n; ++i)
		color[i] = NEW;

	for (int i = 0; i < n; ++i)
	{
		if (color[i] == NEW)
			dfs_visit(i);
	}

	for (int i = 0; i < n; ++i)
	{
		cout << i + 1 << " " << t1[i] << " " << t2[i] << endl;
	}
}

int dist[N];

void bfs(int idx)
{
	queue<int> q;
	q.push(idx);

	for (int i = 0; i < n; ++i)
		dist[i] = INT_MAX;
	dist[idx] = 0;

	int u;
	while (!q.empty())
	{
		u = q.front(); q.pop();
		for (int i = 0; i < n; ++i)
		{
			if (m[u][i] == 0) continue;
			if (dist[i] != INT_MAX) continue;
			dist[i] = dist[u] + 1;
			q.push(i);
		}
	}
	for (int i = 0; i < n; ++i)
	{
		cout << i + 1 << " " <<( (dist[i] == INT_MAX) ? (-1) : dist[i]) << endl;
	}
}


int main()
{
	getMatrix();
	bfs(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], 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 v, k ,u;
	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;
		}
	}
	
	bfs(0);
	
	return 0;
	
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

// ---------------------
// repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF 922337203685477580
typedef long long ll;

int matrix[110][110];
int dist[110];
int n;
queue<int> Q;

int main() {
  REP(x, 110) {
    REP(y, 110) {
      matrix[x][y] = 0;
    }
    dist[x] = (1 << 15);
  }

  // int n;
  cin >> n;

  REP(_, n) {
    int v, num;
    cin >> v >> num;

    REP(i, num) {
      int cv;
      cin >> cv;
      matrix[v][cv] = 1;
    }
  }

  dist[1] = 0;
  Q.push(1);

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

    FOR(v, 1, n + 1) {
      if (matrix[f][v]) {
        Q.push(v);
        dist[v] = min(dist[v], dist[f] + 1);
      }
    }
  }


  FOR(v, 1, n + 1) {
    if (dist[v] == (1 << 15)) {
      cout << v << " -1" << endl;
    } else {
      cout << v << " " << dist[v] << endl;
    }
  }


  return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
using namespace std;
int n;
int D[100];
int matrix[100][100];
void bfs(int src)
{
    cerr<<"bfs root = "<<src<<endl;
    queue<int> q;
    q.push(src);
    D[src]=0;
    while(!q.empty())
    {
        int cur=q.front();
        q.pop();
        cerr<<"visiting "<<cur<<' '<<D[cur]<<endl;
        for(int dst=0;dst<n;dst++)
        {
            if(matrix[cur][dst]==1&&D[dst]!=99999999)
            {
                D[dst]=D[cur]+1;
                q.push(dst);
            }
        }
    }
};

int main()
{
    vector<int> l[101];
    cin>>n;
    for(int i=0;i<n;i++)
    {
        int u,k;
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            int tmp;
            cin>>tmp;
            l[u].push_back(tmp);
        }
    }
    
    for(int i=0;i<100;i++)
    {
        D[i]=99999999;
    }
    
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<n;j++)
        {
            matrix[i][j]=0;
        }
    }
    
    for(int i=1;i<n+1;i++)
    {
        for(int j=0;j<l[i].size();j++)
        {
            matrix[i-1][l[i][j]-1]=1;
        }
    }
    
    for(int i=0;i<n;i++)
    {
        bfs(i);
    }
    
    for(int i=0;i<n;i++)
    {
        cout<<(i+1)<<' '<<D[i]<<endl;
    }
}