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 <stdio.h>
#include <queue>

int time, n;
int d[100], color[100];
int M[100][100];

void bfs(int s) {
    std::queue<int> Q;
    
    for (int i=0; i<100; i++){
        color[i] = 0;
        d[i] = -1;
    }
    
    color[s] = 1;
    d[s] = 0;
    Q.push(s);
    while (!Q.empty()) {
        int u = Q.front(); Q.pop();
        for (int i=0; i<n; i++) {
            if(M[u][i] && color[i] == 0) {
                color[i] = 1;
                d[i] = d[u]+1;
                Q.push(i);
            }
        }
        color[u] = 2;
    }
}

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

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

using namespace std;

int D[110]; // ?????¢????¨???¶
int v, A[100][100], u, k, w;
queue<int> Q;

void bfs(int src) {

	Q.push(src);
	D[src] = 0;

	while (!Q.empty()) {
		int cur = Q.front();
		Q.pop();
		for (int i = 0; i < v; ++i) {
			if (A[cur][i] == 1 && D[i] == 0) {
				D[i] = D[cur] + 1;
				Q.push(i);
			}
		}
	}

	for (int l = 0; l < v; ++l) {
		if (D[l] == 0) { D[l] = -1; }
		if (l == 0) { D[l] = 0; }
		cout << l+1 << " " << D[l] << endl;
	}

}

int main(){
	cin >> v;
	// ???????????§??????v
	for (int i = 0; i < v; ++i) {

		cin >> u >> k;
		// ??????????????????u???k?????\?????????????????°??????

		for (int j = 0; j < k; ++j) {

			cin >> w;
			A[u - 1][w - 1] = 1;

			// ??£??\???????????§?¨??????????????????????????????????

		}
	}

	
	bfs(0);

}

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

int k[1000][1000], n, a, b, c, t, x[1000];
queue<int>Q;
queue<int>R;

int main() {
	memset(x, -1, sizeof(x));
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> a >> b;
		for (int j = 0; j < b; j++) {
			cin >> c;
			k[i][c] = 1;
		}
	}
	Q.push(1);
	x[1] = 0;
	while (!Q.empty()) {
		t++;
		while (!Q.empty()) {
			for (int i = 1; i <= n; i++) {
				if (x[i] == -1 && k[Q.front()][i] == 1) {
					x[i] = t;
					R.push(i);
				}
			}
			Q.pop();
		}
		while (!R.empty()) {
			Q.push(R.front());
			R.pop();
		}
	}
	for (int i = 1; i <= n; i++) {
		cout << i << ' ' << x[i] << endl;
	}
	return 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];
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, 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<iostream>
#include<queue>
using namespace std;
int M[100][100] = {};
int color[100] = {};
int d[100] = {};
int n;
static const int INTFY = -1;


void bfs(int s) {
	int u;
	queue<int> q;
	color[s] = 1;
	d[s] = 0;
	q.push(s);
	while (!q.empty()) {
		u = q.front();q.pop();
		for (int v = 0;v < n;v++) {
			if (M[u][v] == 1 && color[v] == 0) {
				color[v]++;
				d[v] = d[u] + 1;
				q.push(v);
			}
			color[u]++;
		}
	}
	for (int i = 0;i < n;i++) {
		cout << i + 1 << " " << d[i] << endl;
	}
}
int main() {
	int k, m, j;
	cin >> n;
	for (int i = 0;i < n;i++) {
		cin >> m >> k;
		for (int l = 0;l < k;l++) {
			cin >> j;
			M[m - 1][j - 1] = 1;
		}
	}
	for (int i = 0;i < n;i++) {
		d[i] = INTFY;
	}
	bfs(0);

	


	return 0;
}

C++: #include<bits/stdc++.h>
#define ll long long int
#define FOR(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define REP(i,n) FOR(i,0,n)
#define REP1(i,n) FOR(i,1,n)

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);
  REP(i, n) d[i] = INFTY;
  d[s] = 0;
  int u;
  while ( !q.empty() ) {
    u = q.front();
    q.pop();
    REP(v, n) {
      if ( M[u][v] == 0 ) continue;
      if ( d[v] != INFTY ) continue;
      d[v] = d[u] + 1;
      q.push( v );
    }
  }
  REP(i, n) {
    cout << i+1 << " " << ( (d[i] == INFTY) ? (-1) : d[i] ) << endl;
  }
}

int main() {
  int u, k, v;

  cin >> n;
  REP(i, n) {
    REP(j, n) M[i][j] = 0;
  }

  REP(i, n) {
    cin >> u >> k;
    u--;
    REP(j, k) {
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }

  bfs(0);
  return 0;
}