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 <algorithm>
#include <iostream>
#include <string>
#include <cstring>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <deque>
#include <iomanip>
#include <limits>
#include <map>
#include <queue>
#include <stack>
#include <vector>

#define FOR(i,k,n) for(int (i) = (k); (i) < (n); ++(i))
#define rep(i,n) FOR(i,0,n)
#define pb push_back
#define all(v) begin(v), end(v)
#define debug(x) cerr << #x << ": " << x << endl
#define debug2(x,y) cerr << #x << ": " << x << ", " << #y << ": " << y << endl

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector< vector<int> > vvi;
template<class T> using vv=vector< vector<T> >;
typedef deque<int> di;
typedef deque< deque<int> > ddi;


int main() {
    int n;
    cin >> n;
    vi vlist[101];
    rep(i,n) {
        int u,k;
        cin >> u >> k;
        rep(i,k) {
            int v;
            cin >> v;
            vlist[u].pb(v);
        }
    }

    queue<int> Q;
    int count[101];
    Q.push(1);

    while(!Q.empty()) {
        int i = Q.front();
        Q.pop();
        
        rep(j,vlist[i].size()) {
            if(count[vlist[i][j]] == 0 && vlist[i][j] != 1) {
                count[vlist[i][j]] = count[i] + 1;
                Q.push(vlist[i][j]);
            }
        }
    }
    FOR(i,1,n+1) {
        if(i != 1 && count[i] == 0) {
            cout << i << " " << -1 << endl;
        } else {
            cout << i << " " << count[i] << endl;
        }
    }

	return 0;
}

C++: #include<iostream>
#include<queue>
using namespace std;
const int MAXN = 105;
const int INF = 1<<21;
int a[105][105];
int d[MAXN];
int n;


void bfs(int s)
{
	for(int i = 0; i < n; i++)
	{
		d[i] = INF;
	}
	queue<int> q;
	q.push(s);
	d[s] = 0;
	
	int u;
	while(!q.empty())
	{
		u = q.front(); q.pop();
		for(int v = 0; v < n; v++)
		{
			if(d[v] != INF)
				continue;
			if(a[u][v] == 0)
				continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	
	for(int i = 0; i < n; i++)
	{
		cout << i+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--;
			a[u][v] = 1;
		}
	}
	bfs(0);
	return 0;
}

C++: //============================================================================
// Name        : Graph.cpp
// Author      : Ken
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

struct Node{
	int id;
	vector<int> adjNodes;
	bool isFound;
	int discover_time;
	int finish_time;
	int distance;
};

class Graph{
public:
	vector<Node> nodeList;
	map<int, vector<Node*> > distanceMap;
	Graph():nodeList(), distanceMap(){}

	void insert(Node& i){
		nodeList.push_back(i);
	}

	void SearchDepthFirst(int source_id, int& timer){
		Node& source_node = nodeList.at(source_id);
		source_node.isFound = true;
		source_node.discover_time = timer;
		for(int i=0; i<source_node.adjNodes.size(); i++){
			if(nodeList.at(source_node.adjNodes.at(i)).isFound == false){
				timer ++;
				nodeList.at(source_node.adjNodes.at(i)).isFound = true;
				nodeList.at(source_node.adjNodes.at(i)).discover_time = timer;
				SearchDepthFirst(source_node.adjNodes.at(i), timer);
				nodeList.at(source_node.adjNodes.at(i)).finish_time = timer;
			}
		}
		timer++;

		source_node.finish_time = timer;
	}

	void SearchDepthFirstAll(int& timer){
		for(int i=0; i<nodeList.size(); i++){
			if(nodeList.at(i).isFound == false){
				SearchDepthFirst(i, timer);
				timer++;
			}
		}
	}

	void writeSearchResult(){
		for(int i=0; i<nodeList.size(); i++){
			cout << nodeList.at(i).id+1 << " " << nodeList.at(i).discover_time << " " << nodeList.at(i).finish_time << "\n";
		}
	}


	void addDistance(){
		vector<Node*> vec;
		vec.push_back(&nodeList.at(0));
		distanceMap[0] =vec;
		int cur_distance=0;

		while(cur_distance < nodeList.size()){
			vector<Node*>& vec_p_node = distanceMap[cur_distance];
			vector<Node*> empty_vec;
			distanceMap[cur_distance+1] = empty_vec;
			for(int i=0; i<vec_p_node.size(); i++){
				vector<int>& adjNodes = vec_p_node.at(i)->adjNodes;
				for(int j=0; j<adjNodes.size(); j++){
					if(nodeList.at(adjNodes.at(j)).distance == -1){
					    nodeList.at(adjNodes.at(j)).distance = cur_distance+1;
					    distanceMap[cur_distance+1].push_back(&nodeList.at(adjNodes.at(j)));
					}
				}
			}
			if(distanceMap[cur_distance+1].size() == 0){
				break;
			}

			cur_distance++;
		}
	}

	void writeDistance(){
		for(int i=0; i<nodeList.size(); i++){
			cout << i+1 << " " << nodeList.at(i).distance << "\n";
		}
	}

	void write(){
		for(int i=0; i<nodeList.size(); i++){
			Node& node = nodeList.at(i);
			cout << node.id << " " << node.adjNodes.size() << " ";

			for(int j=0; j<node.adjNodes.size(); j++){
				cout << node.adjNodes.at(j) << " ";
			}
			cout << "\n";
		}

	}

	void writeMap(){
		map<int, vector<Node*> >::iterator p;
		for(p=distanceMap.begin(); p!=distanceMap.end(); ++p){
			cout << "distance: " << p->first << ", id: ";
			vector<Node*>::iterator p2;
			for(p2=p->second.begin(); p2!=p->second.end(); ++p2){
				cout << (*p2)->id << " ";
			}
			cout << "\n";
		}
	}
};

void writeMatrix(vector<vector<int> > matrix){
	for(int i=0; i<matrix.size(); i++){
		for(int j=0; j<matrix.at(i).size()-1; j++){
			cout << matrix.at(i).at(j) << " ";
		}
		cout << matrix.at(i).at(matrix.at(i).size()-1);
		cout << "\n";
	}
}

int main() {
	int n;
	cin >> n;
	Graph g;

	for(int i=0; i<n; i++){
		int id, k;
		cin >> id >> k;
		vector<int> adjNodes;
		for(int j=0; j<k; j++){
			int input;
			cin >> input;
			adjNodes.push_back(input-1);
		}
		sort(adjNodes.begin(), adjNodes.end());
		Node node = {id-1, adjNodes, false, -1, -1, -1};
		g.insert(node);
	}

	//g.write();
	//int timer = 1;
	//g.SearchDepthFirstAll(timer);
	//g.writeSearchResult();

	g.nodeList.at(0).distance = 0;
	g.addDistance();
	g.writeDistance();

	return 0;
}