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 <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <queue>
using namespace std;

bool A[110][110],flag[110];
int d[110];
int n;

void bfs(){
	queue<int> Q;
	Q.push(1);
	d[1]=0;
	while(Q.empty()==0){
		int u=Q.front();
		Q.pop();
		for(int i=2;i<=n;i++){
			if(A[u][i]==true && flag[i]==false ){
				flag[i]=true;
				Q.push(i);
				d[i]=d[u]+1;
			}
		}
	}
	for(int i=2;i<=n;i++) if(flag[i]==false) d[i]=-1;
	return ;
}

int main(){
	int a,b,c;
	cin>>n;
	for(int i=1;i<=n;i++){
		flag[i]=false;
			for(int j=1;j<=n;j++){
				A[i][j]=false;
		}
	}
	for(int i=1;i<=n;i++){
		cin>>a>>b;
		for(int j=1;j<=b;j++){
			cin>>c;
			A[a][c]=true;
		}
	}
	bfs();
	for(int i=1;i<=n;i++) cout<<i<<" "<<d[i]<<endl;	
	return 0;
}

C++: // -*- mode:c++; coding:utf-8; c-basic-offset:2; -*-
// ALDS1_11_C: Breadth First Search

#include <algorithm>
#include <cstdio>
#include <queue>

using uint = unsigned int;

class Graph {
  const uint n_;
  uint* const g_;
  int* const depth_;
  
public:
  Graph(uint n) : n_(n),
                  g_(new uint[(n_*n_)]),
                  depth_(new int[n])
  {
    std::fill(g_, g_+(n_*n_), 0u);
  }

  ~Graph()
  {
    delete[] g_;
    delete[] depth_;
  }
  
  uint* operator [](uint i) const { return g_+(n_*i); }

  int* depth() const { return depth_; }

  void bfs()
  {
    init_depth();
    std::queue<uint> q;
    auto i = 0u;
    q.push(i);
    depth_[i] = 0;
    while (!q.empty()) {
      i = q.front();
      for (auto j = i+1; j < n_; ++j) {
        if ((*this)[i][j] && depth_[j] == -1) {
          q.push(j);
          depth_[j] = depth_[i]+1;
        }
      }
      q.pop();
    }
  }

private:
  void init_depth()
  {
    std::fill(depth_, depth_+(n_), -1);
  }
};

int main()
{
  uint n;
  std::scanf("%u", &n);

  Graph g(n);

  uint u, k, v;
  for (auto i = 0u; i < n; ++i) {
    std::scanf("%u %u", &u, &k);
    for (auto j = 0u; j < k; ++j) {
      std::scanf("%u", &v);
      g[u-1][v-1] = 1;
    }
  }

  g.bfs();
  auto depth = g.depth();
  for (auto i = 0u; i < n; ++i) {
    std::printf("%u %d\n", i+1, depth[i]);
  }
}

// eof

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

int n, dd[101], f[101], tmap[101][101];
int color[101], t = 0;
queue<int> Q;


void a(){
	while (!Q.empty()){
		int d = Q.front();
		Q.pop();
		for (int i = 1; i <= n; i++){
			if (color[i] == 0 && tmap[d][i] == 1){
				Q.push(i);
				color[i] = 1;
				dd[i] = dd[d] + 1;
			}
		}
	}
}


int main(){
	cin >> n;
	for (int i = 0; i < 100; i++){
		f[i] = color[i] = 0;
		dd[i] = -1;
		for (int j = 0; j < 100; j++){
			tmap[i][j] = 0;
		}
	}

	int u, k, v;

	for (int i = 0; i < n; i++){
		cin >> u >> k;
		for (int j = 0; j < k; j++){
			cin >> v;
			tmap[u][v] = 1;
		}
	}
	color[1] = 1;
	Q.push(1);
	dd[1] = t;
	a();
	for (int i = 1; i <= n; i++){
		cout << i << " " << dd[i] << endl;
	}
	return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<stack>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#define _USE_MATH_DEFINES // M_PI????????????????????????
#include<math.h>
#include<queue>
#pragma warning(disable:4996)
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] ) << "\n";
	}
}

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;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,o,n) for(long long i = o;i<n;i++)
#define oneforall ios::sync_with_stdio(false);cin.tie(0);
#define all(v) (v).begin(),(v).end()
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) long long __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
#define int long long 
const long long inf=1e18;
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
typedef vector<int> vi;
typedef vector<long long> vl;
typedef long long ll;
typedef vector<pair<long, long > > vpll;
typedef vector<pair<int, int > > vpii;
#define FORR(x,arr) for(auto& x:arr)
#define ZERO(a) memset(a,0,sizeof(a))





//3111111111111111111111111111111

	int n;
	vi adj[310];
	bool visit[310];
	int dep[310];
	void bfs(){

		visit[1] = 1;
		queue<int> queue1;
		queue1.push(1);
		while(!queue1.empty()){
			int tmp = queue1.front();
			queue1.pop();
			FORR(x1,adj[tmp])if(!visit[x1]){
				visit[x1] = 1;
				queue1.push(x1);
				dep[x1] = dep[tmp]+1;
			}
		}
	}

	void solve(){
		
		in(n);
		memset(dep,-1,sizeof(dep));
		dep[1] = 0;
		FOR(i,0,n){
			ini(x,x1);
			FOR(i1,0,x1){
				ini(tmp);
				adj[x].push_back(tmp);
			}
		}
		bfs();
		FOR(i,1,n+1){
			out(i,dep[i]);
		}







		
		
	}























int32_t main() {
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall 
	oneforall

	solve();
	


	return 0;
}