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;

int main(){
	int n,m,l,i,j,p;
	int f[1000][1000];
	int D[1000] = {};
	cin >> n;
	for(i = 0; i < n; i++){
		cin >> m;
		cin >> p;
		for(j = 0; j < p; j++){
			cin >> l;
			f[m][l] = 1;
		}
	}
	queue<int> Q;
	Q.push(1);
	while(!Q.empty()){
		int cur = Q.front();
		Q.pop();
		for(i = 1; i <= n; i++){
			if(f[cur][i] == 1 && D[i] == 0){
				D[i] = D[cur] + 1;
				Q.push(i);
			}
		}
	}				
	for(i = 1; i <= n; i++){
		if (D[i] == 0 && i !=1 )
			D[i] = -1;
		cout << i << " " << D[i] << endl;
	}
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
#include<set>
#include<cstdio>
#include<cmath>
#include<deque>
#include<numeric>
#include<queue>
#include<stack>
#include<cstring>
#include<limits>
#include<functional>
#include<unordered_set>
#include<iomanip>
#include<cassert>
#include<regex>
#include<bitset>
#include<complex>
#include<chrono>
#include<random>
#define rep(i,a) for(int i=(int)0;i<(int)a;++i)
#define rrep(i,a) for(int i=(int)a-1;i>=0;--i)
#define REP(i,a,b) for(int i=(int)a;i<(int)b;++i)
#define RREP(i,a,b) for(int i=(int)a-1;i>=b;--i)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(),x.end()
typedef std::vector<int> vi;
typedef std::vector<std::vector<int>> vvi;
typedef std::vector<long long> vl;
typedef std::vector<std::vector<long long>> vvl;
#define out(x) cout<<x<<"\n";
using ll=long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;

ll gcd(ll n, ll m) {
    ll tmp;
    while (m!=0) {
        tmp = n % m;
        n = m;
        m = tmp;
    }
    return n;
}

ll lcm(ll n, ll m) {
    return abs(n) / gcd(n, m)*abs(m);//gl=xy
}
 
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
 
using namespace std;

template<typename T>//O(V^2)　全点間距離 辺のコストがすべて等しいとき,ダイクストラより高速に使える
vector<vector<T>> bfs(vector<vector<T>> &g){
    queue<T>q;
    int n=g.size();
    T INFTY=numeric_limits<T>::max();
    vector<vector<T>>dist(n,vector<T>(n,INFTY));
    for(int i=0;i<n;++i){
        dist[i][i]=0;
        q.emplace(i);
        while(!q.empty()){
            int v=q.front();
            q.pop();
            for(auto x:g[v]){
                if(dist[i][x]==INFTY){
                    q.emplace(x);
                    dist[i][x]=dist[i][v]+1;
                }
            }
        }
    }
    return dist;
}

void solve(){
  int n;
  cin>>n;
  vector<vector<int>>g(n);
  rep(i,n){
      int id;
      cin>>id;
      id--;
      int k;
      cin>>k;
      rep(j,k){
          int a;
          cin>>a;
          a--;
          g[id].pb(a);
      }
  }
  auto d=bfs(g);
  rep(i,n){
      cout<<i+1<<" "<<(d[0][i]!=numeric_limits<int>::max()?d[0][i]:-1)<<"\n";
  }
}


int main(){
    ios::sync_with_stdio(false);
  cin.tie(0);
    cout<<fixed<<setprecision(15);
  solve();
    return 0;
}

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

void BFS(vector<vector<long long> >& Graph, long long start, vector<long long>& reach, vector<bool>& Flag) {
	queue<long long>Q;
	Q.push(start);
	Flag.at(start) = true;
	reach.at(start) = 0;
	while (!Q.empty()) {
		long long v = Q.front(); Q.pop();
		for (long long i = 0; i < Graph[v].size(); i++) {
		    long long to = Graph[v].at(i);
			if (!Flag.at(to - 1)) {
				reach.at(to - 1) = reach.at(v) + 1;
				Flag.at(to - 1) = true;
				Q.push(to - 1);
			}
		}
	}
}
int main() {
	long long N; cin >> N;
	vector<vector<long long> >Graph(N);
	for (long long i = 0; i < N; i++) {
		long long virtex, num;
		cin >> virtex >> num;
		for (long long j = 0; j < num; j++) {
			long long to; cin >> to;
			Graph.at(virtex - 1).push_back(to);
		}
	}
	vector<long long>reach(N, -1);
	vector<bool>Flag(N, false);
	BFS(Graph, 0, reach, Flag);
	for (long long i = 0; i < N; i++) {
		cout << i + 1 << ' ' << reach.at(i) << endl;
	}
}