Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, &g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

func fillDistancesByBreadthFirstSearch(g *DirectedGraph, startNode *DirectedGraphNode) {
	startNode.visited = true
	startNode.d = 0

	queue := Queue{}
	queue.enqueue(startNode)
	for !queue.isEmpty() {
		u := queue.dequeue().node
		for _, adjacent := range u.adjacents {
			if !adjacent.visited {
				adjacent.visited = true
				adjacent.d = u.d + 1
				adjacent.parent = u
				queue.enqueue(adjacent)
			}
		}
		u.visited = true
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	// fmt.Println(g)
	fillDistancesByBreadthFirstSearch(g, &g.nodes[1])
	// fmt.Println(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		distance := node.d
		if distance == infty {
			distance = -1
		}
		fmt.Println(node.key, distance)
	}
}

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

#define M_PI       3.14159265358979323846   // pi

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll> VI;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, ll, ll> t4;
typedef tuple<ll, ll, ll, ll, ll> t5;

#define rep(a,n) for(ll a = 0;a < n;a++)
#define repi(a,b,n) for(ll a = b;a < n;a++)

using namespace std;

static const ll INF = 1e15;

struct warshall_floyd {
	static void solve(vector<vector<ll>>& d) {
		int n = d.size();
		rep(k, n) {
			rep(i, n) {
				rep(j, n) {
					d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
				}
			}
		}
	}
};

int main() {
	int n;
	cin >> n;
	vector<vector<ll>> dist(n, vector<ll>(n, INF));
	rep(i, n) {
		dist[i][i] = 0;
	}
	rep(i, n) {
		int a, v;
		cin >> a >> v;
		rep(j, v) {
			int t;
			cin >> t;
			t--;
			dist[i][t] = 1;
		}
	}
	warshall_floyd::solve(dist);
	rep(i, n) {
		if (dist[0][i] == INF) {
			cout << i + 1 << " " << -1 << endl;
		}
		else {
			cout << i + 1 << " " << dist[0][i] << endl;
		}
	}
	return 0;
}

C++: //#define LOCAL

#include<bits/stdc++.h>

using namespace std;

#define rep(a, b) for(int i = a; i <= b; i++)
#define mst(a) memset(a, 0, sizeof(a))

const int MAX = 1e2 + 10;


bool mtx[MAX][MAX];
int vis[MAX];
int n;

queue<int> q;

void init(void)
{
	while(!q.empty())
		q.pop();
	mst(vis);
	mst(mtx);
	n = 0;
	return;
}

bool check(int x, int y)
{
	if(mtx[x][y] && !vis[y])
		return true;
	return false;
}

void Bfs(void)
{
	q.push(1);
	while(!q.empty())
	{
		int cur = q.front();
		q.pop();
		rep(1, MAX - 10)
		{
			if(check(cur, i))
			{
				q.push(i);
				vis[i] = vis[cur] + 1;
			}
		}
	}
	return;
}

int main()
{
#ifdef LOCAL
	freopen("in.txt", "r", stdin);
#endif

	while(~scanf("%d", &n))
	{
		rep(1, n)
		{
			int row;
			scanf("%d", &row);
			int num;
			scanf("%d", &num);
			for(int j = 1; j <= num; j++)
			{
				int tmp;
				scanf("%d", &tmp);
				mtx[row][tmp] = true;
			}
		}
		Bfs();
		rep(1, n)
		{
			printf("%d %d\n", i, vis[i]);
		}
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define REP(i,n) for(int i=0;i<(n);i++)
#define REAP(i,a,n) for(int i=(a);i<(n);i++)
#define YES cout<<"Yes"<<endl
#define NO cout<<"No"<<endl
#define fr first
#define sc second
#define pb push_back
#define All(v) v.begin(),v.end()
typedef long long ll;

int table[101][101];

void init(){
    REP(i,101){
        REP(j,101){
            table[i][j]=1e9;
            if(i==j)table[i][j]=0;
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    init();
    int u,k,v;
    REP(i,n){
        cin >> u >> k;
        REP(j,k){
            cin >> v;
            table[u-1][v-1]=1;
        }
    }

    REP(k,n){
        REP(i,n){
            REP(j,n){
                table[i][j]=min(table[i][j],table[i][k]+table[k][j]);
            }
        }
    }
    REP(i,n){
        cout << i+1 << " " << ((table[0][i]<n)?table[0][i]:-1);
        cout << endl;
    }
}

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
#include<queue>
using namespace std;
#define N 1000
bool M[N][N];

int main(){
    int n,u,k,v;
    queue<int> Q;
 
    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]=true;
	}
    }
   
    int d[N]={0};
    Q.push(0);
    while(!Q.empty()){
	u=Q.front();
	Q.pop();
	for(int i=1;i<n;i++){
	    if(M[u][i] && d[i]==0){
		d[i]=d[u]+1;
		Q.push(i);
	    }
	}
    }

    for(int i=0;i<n;i++){
	if(i!=0 && d[i]==0) d[i]=-1;
	printf("%d %d\n",i+1,d[i]);
    }

    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#define N 100
using namespace std;

int color[N], d[N];
int M[N][N];


void bfs(int n) {
	queue<int> Q;
	d[0] = 0;
	for (int i = 1;i < n;i++) d[i] = -1;
	Q.push(0);
	while (!Q.empty()) {
	  for (int i = 0;i < n;i++)
		  if (M[Q.front()][i] == 1) {
			  if (color[i] == 0) {
				  d[i] = d[Q.front()] + 1;
				  color[i] = 1;
				  Q.push(i);
			  }
		  }
		  Q.pop();
	}
	for (int i = 0;i < n;i++)
		cout << i + 1 << " " << d[i] << endl;
}


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

	bfs(n);

}