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<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++: // Ref : https://book.mynavi.jp/ec/products/detail/id=35408

#include <iostream>
#include <queue>
#include <limits.h>

using namespace std;
static const int NMAX = 100;
int N, D[NMAX] = {};
bool G[NMAX][NMAX] = { { false } };

void breadthFirstSearch(int base) {
	int ix;
	for (int i = 0; i < N; i++) {
		D[i] = INT_MAX;
	}

	D[base] = 0;
	queue<int> q;
	q.push(base);
	while (!q.empty()) {
		ix = q.front(); q.pop();
		for (int i = 0; i < N; i++) {
			if (!G[ix][i]) continue;
			if (D[i] != INT_MAX) continue;
			D[i] = D[ix] + 1;
			q.push(i);
		}
	}

	for (int i = 0; i < N; i++) {
		cout << i + 1 << " " << ((D[i] == INT_MAX) ? (-1) : D[i]) << endl;
	}
}

int main() {
	int ix, deg, cache;
	cin >> N;

	for (int i = 0; i < N; i++) {
		cin >> ix >> deg;
		for (int j = 0; j < deg; j++) {
			cin >> cache;
			G[ix-1][cache-1] = true;
		}
	}

	breadthFirstSearch(0);

	return 0;
}

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

const int MAXV = 1010, MAXE = 1000000;

struct edge { int u, v, weight, next; } g[MAXE];


int n;
int head[MAXV], idx;

int parent[MAXV], visited[MAXV], dist[MAXV];

void bfs(int u){
    memset(parent, -1, sizeof(parent));
    memset(visited, 0, sizeof(visited));
    memset(dist, -1, sizeof(dist));
    
    queue<int> q;
    q.push(u);
    visited[u] = 1;
    dist[u] = 0;
    
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        for (int i = head[u]; ~i; i = g[i].next) {
            int v = g[i].v;
            if (!visited[v]) {
                q.push(v);
                visited[v] = 1, parent[v] = u, dist[v] = dist[u] + 1;
            }
        }
    }
}

int main(int argc, char *argv[])
{
    
 
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    idx = 0;
    memset(head, -1, sizeof(head));
    
    cin >> n;
    
    for (int i = 0, u, m, v; i < n; i++) {
        cin >> u >> m;
        for (int j = 0; j < m; j++) {
            cin >> v;
            g[idx] = edge{u, v, 0, head[u]};
            head[u] = idx++;
        }
    }
    
    bfs(1);
    
    for (int i = 1; i <= n; i++) {
        cout << i << " " << dist[i] << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <stdio.h>
#define REP(i, n) for(int i = 0;i < n;i++)

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);
	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[n][n] = 0;
	}

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

	REP(i, n)
	{
		REP(j, n)
		{
			cout << M[i][j];
		}
		cout << endl;
	}

	bfs(0);
	return 0;
}

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

int main() {
	int n;
	std::cin >> n;
	std::vector<int> d(n, -1);
	std::vector<int> dtmp(n, -1);
	std::vector<std::vector<int>> vec(n);
	for (int i = 0; i < n; i++) {
		int u, k;
		std::cin >> u >> k;
		while (k--) {
			int a;
			std::cin >> a;
			vec[i].push_back(a - 1);
		}
	}

	dtmp[0] = 0;
	for (int i = 0; i < n; i++) {
		d = dtmp;
		for (int idx = 0; idx < n; idx++) {
			if (d[idx] >= 0) {
				for (int j = 0; j < vec[idx].size(); j++) {
					if (dtmp[vec[idx][j]] == -1) {
						dtmp[vec[idx][j]] = i + 1;
					}
				}
			}
		}
	}

	for (int i = 0; i < n; i++) {
		std::cout << i + 1 << " " << d[i] << std::endl;
	}
}