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 _GLIBCXX_DEBUG
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i < (n + 1); ++i)
using namespace std;
using ll = long long;
const int INF = +100100100;
// typedef pair<int,int> P;

vector<int> D(150, INF);
vector<vector<int>> M(150, vector<int>(150));
int n;

void bfs()
{
    int s = 0;
    queue<int> Q;
    Q.push(s);
    D[0]=0;
    while (!Q.empty())
    {
        int u = Q.front();
        Q.pop();
        rep(v, n)
        {
            // 訪れたことがない
            if (D[v] == INF&&M[u][v]==1)
            {
                D[v] = D[u] + 1;
                Q.push(v);
            }
        }
    }
    rep(i,n)if(D[i]==INF)D[i]=-1;
}

int main()
{
    cin >> n;
    vector<list<int>> L(n);
    rep(i, n)
    {
        int u, e;
        cin >> u >> e;
        rep(j, e)
        {
            int v;
            cin >> v;
            --v;
            L[i].push_back(v);
        }
    }
    
    rep(i, n)
    {
        rep(j, n)
        {
            list<int>::iterator it = find(L[i].begin(), L[i].end(), j);
            if (it != L[i].end())
            {
                M[i][j] = 1;
                L[i].erase(it);
            }
        }
    }
    bfs();
    rep(i,n){
        printf("%d %d\n",i+1,D[i]);
    }
    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 <bits/stdc++.h>

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define FOR(i,n,m) for(int i=(int)(n); i<=(int)(m); i++)
#define RFOR(i,n,m) for(int i=(int)(n); i>=(int)(m); i--)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)
#define setp(n) fixed << setprecision(n)

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }

#define ll long long
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll,ll>
#define pi pair<int,int>

#define all(a) (a.begin()),(a.end())
#define rall(a) (a.rbegin()),(a.rend())
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define ins insert

using namespace std;

//-------------------------------------------------
//--Graph Template
//-------------------------------------------------
template<class E>
struct Graph
{
    vector<vector<E> > adj;
    Graph(int N):adj(N){}
    virtual void add_edge(int v, E e){adj[v].push_back(e);}
    vector<E>& operator[](int v){return adj[v];}
    inline int size(){return adj.size();}
};

struct NormalEdge {
    int to;
    NormalEdge(int to):to(to){}
};

struct UWGraph : public Graph<NormalEdge>
{
    UWGraph(int N):Graph(N){}
    void add_edge(int v, int e){adj[v].push_back({e});}
};

//-------------------------------------------------
//--Dist BFS
//-------------------------------------------------
template<class E>
vector<int> distBFS(Graph<E> &G, int s)
{
    vector<int> dist(G.size(),-1); dist[s]=0;
    queue<int> que; que.push(s);
    while(!que.empty()){
        int v = que.front(); que.pop();
        for(auto e:G[v]){
            if (dist[e.to]!=-1) continue;
            dist[e.to]=dist[v]+1;
            que.push(e.to);
        }
    }
    return dist;
}

//-------------------------------------------------

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N; cin>>N;
    UWGraph G(N);
    rep(i,N){
        int u,k; cin>>u>>k; u--;
        rep(i,k){
            int v; cin>>v; v--;
            G.add_edge(u,v);
        }
    }
    auto dist = distBFS(G,0);
    rep(i,N){
        cout<<i+1<<" "<<dist[i]<<"\n";
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
#define MAX_V 110

int main() {
    
    vector<vector<int>> G(MAX_V);
    int n; cin >> n;
    for(int i=0; i<n; i++){
        int v, k; cin >> v >> k;

        for(int j=0; j<k; j++){
            int u; cin >> u;
            G[v].push_back(u);
        }
    }

    vector<int> dist(MAX_V, -1);
    dist[1] = 0;

    queue<int> q;
    q.push(1);
    while(!q.empty()){

        int v = q.front();
        q.pop();

        for(int i=0; i<G[v].size(); i++){
            int u = G[v][i];
            if(dist[u] == -1){
                dist[u] = dist[v] + 1;
                q.push(u);
            }
        }
    }

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