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>
using namespace std;
#define int long long

bool isprime(int n){
    double rootn = sqrt(n);
    if (n < 2){
        return false;
    }
    else if (n == 2){
        return true;
    }
    else if (n % 2 == 0){
        return false;
    }
    else{
        for(int i = 3; i <= rootn; i += 2){
            if(n % i == 0){
                return false;
            }
        }
        return true;
    }
}

// 空のベクトルを二つ渡す。N (>=2) 以下の素数を primes に順番に入れる。
void prime_vectors(int N, vector<int>& primes, vector<bool>& is_prime){
    primes = {};
    is_prime = {};
    for(int i=0; i<=N; i++){
        is_prime.push_back(true);
    }

    primes.push_back(2);
    for(int j=4; j<=N; j+=2){
        is_prime[j] = false;
    }

    int i;
    for(i=3; i*i<=N; i+=2){
        if(!is_prime[i]) continue;
        primes.push_back(i);
        for(int j=2*i; j<=N; j+=i){
            is_prime[j] = false;
        }
    }

    for(; i<=N; i+=2){
        if(is_prime[i]){
            primes.push_back(i);
        }
    }
}

signed main(){
    // cout << fixed << setprecision(10) << flush;

    int n;
    cin >> n;
    vector<vector<int>> e(n);
    for(int i=0; i<n; i++){
        int u, k;
        cin >> u >> k;
        for(int j=0; j<k; j++){
            int v;
            cin >> v;
            e[i].push_back(v-1);
        }
    }

    int d[n];
    for(int i=0; i<n; i++){
        d[i] = -1;
    }

    queue<int> q;
    q.push(0);
    d[0] = 0;
    while(!q.empty()){
        int v = q.front();
        q.pop();
        for(int i=0; i<e[v].size(); i++){
            if(d[e[v][i]] == -1){
                d[e[v][i]] = d[v] + 1;
                q.push(e[v][i]);
            }
        }
    }

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

    return 0;
}

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

#define rep(i, a, b) for (int i = a; i < (int)(b); ++i)
#define rrep(i, a, b) for (int i = b - 1; i >= (int)(a); --i)

using namespace std;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;

void bfs(const vvi& g, vi& ds, int i) {
    int n = g.size();

    vector<bool> seen(n, false);
    queue<int> queue;
    queue.push(i);
    ds[i] = 0;
    seen[i] = true;

    while (!queue.empty()) {
        int v = queue.front();
        queue.pop();

        for (auto itr = g[v].begin(); itr != g[v].end(); ++itr) {
            if (!seen[*itr]) {
                queue.push(*itr);
                ds[*itr] = ds[v] + 1;
                seen[*itr] = true;
            }
        }
    }

    rep(i, 0, n) {
        if (!seen[i]) { ds[i] = -1; }
    }
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    vvi g(n);
    rep(i, 0, n) {
        int u, k;
        cin >> u >> k;

        rep(j, 0, k) {
            int v;
            cin >> v;
            g[u - 1].push_back(v - 1);
        }
    }

    vi ds(n, 0);

    bfs(g, ds, 0);
    rep(i, 0, n) {
        cout << i + 1 << " " << ds[i] << endl;
    }

    return 0;
}

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

int main(){
	vector<int> graph[100];
	queue<int> que;
	int d[100];
	int n;
	cin >> n;
	for(int i = 0;i < n;i++){
		int now,m;
		cin >> now >> m;
		for(int j = 0;j < m;j++){
			int t;
			cin >> t;
			graph[now - 1].push_back(t - 1);
		}
		d[i] = -1;
	}
	d[0] = 0;
	que.push(0);
	while(!que.empty()){
		int num = que.front();
		que.pop();
		for(int i = 0;i < graph[num].size();i++){
			if(d[graph[num][i]] == -1) {
				d[graph[num][i]] = d[num] + 1;
				que.push(graph[num][i]);
			}
		}
	}
	for(int i = 0;i < n;i++){
		cout << i + 1 << " " << d[i] << endl;
	}
	return 0;
}