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 rep(i, a, b) for (int i = (a); i < (int)(b); i++)
#define rrep(i, a, b) for (int i = (a); i >= (int)(b); i--)
#define all(x) (x).begin(), (x).end()
using i32 = int32_t;
using i64 = int64_t;
using f32 = float;
using f64 = double;
using P   = pair<int, int>;

template <class T>
bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    } else {
        return false;
    }
}
template <class T>
bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    } else {
        return false;
    }
}

template <class T>
void dump_vec(const vector<T>& v) {
    auto len = v.size();
    rep(i, 0, len) {
        cout << v[i] << (i == (int)len - 1 ? "\n" : " ");
    }
}

struct FastIO {
    FastIO() {
        cin.tie(0);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(20);
    }
} FASTIO;

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

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

signed main() {
    int N;
    cin >> N;
    vector<vector<int>> G(N);
    rep(i, 0, N) {
        int id, k;
        cin >> id >> k;
        id--;
        rep(j, 0, k) {
            int u;
            cin >> u;
            u--;
            G[id].push_back(u);
        }
    }

    const auto inf = 1 << 30;
    vector<int> dist(N, inf);
    dist[0] = 0;
    queue<P> q;
    q.push(make_pair(0, 0));
    while (!q.empty()) {
        auto pi = q.front();
        q.pop();
        auto u = pi.first, cost = pi.second;
        for (auto& to : G[u]) {
            if (chmin(dist[to], cost + 1)) {
                q.push(make_pair(to, dist[to]));
            }
        }
    }

    rep(i, 0, N) {
        cout << i + 1 << " " << (dist[i] == inf ? -1 : dist[i]) << "\n";
    }
}

C++: //
//
//  algoC.cpp - created by us162022
//
#include <iostream>
#include <queue>
using namespace std;
struct Node{
  int u,k,v[99];
  int distance;
};

int main(int argc, char *argv[])
{
  int n;
  Node node[100];
  queue<Node> que;

  cin >> n;

  for(int i=0; i<n; i++){
    cin >> node[i].u >> node[i].k;

    for(int j=0; j<node[i].k; j++)
      cin >> node[i].v[j];

    node[i].distance=-1;
  }

  node[0].distance = 0;
  que.push(node[0]);

  while(!que.empty()){
    Node fro = que.front();

    for(int i=0; i<fro.k; i++){
      int x = fro.v[i]-1;
  
      if(node[x].distance==-1)
	    node[x].distance = fro.distance+1;

      que.push(node[x]);
    }

    que.pop();
  }

  for(int i=0; i<n; i++)
    cout << node[i].u << " " << node[i].distance << endl;

}

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

int A[100][100];//隣接行列
int n;
int D[100];  //訪問状態を保持　距離で

void bfs(int s) {
	queue<int> Q;
	Q.push(s);
	D[s] = 0; 
	while (! Q.empty()) {
		int cur = Q.front();
		Q.pop();
		for (int d=0; d<n; ++d) {
			if (A[cur][d] == 1 && D[d] == -1) {
				D[d] = D[cur]+1;
				Q.push(d);
			}
		}
	}
}

int main() {
	cin >> n;
	int p,q,r;
	for (int i=0; i<n; ++i) {
		cin >> p >> q;
		D[i] = -1; //到達不可能の時-1
		for (int i=0; i<q; ++i) {
			cin >> r;
			A[p-1][r-1] = 1;
		}
	}
	bfs(0);
	for (int i=0; i<n; ++i) {
		cout << i+1 << " " << D[i] << endl;
	}
    return 0;
}

C++: #include<cstdio>
#include<functional>
#include<algorithm>
using namespace std;
int main(void)
{
	int i,u,j,n1,c1;
	int n,k[101],v[101][100],c[101];
	int q[100],nn[100],p1,p2;
	scanf("%d",&n);
	for(i=1;i<=n;i++)	{
		scanf("%d %d",&u,&k[i]);
		for(j=0;j<k[i];j++)	{
			scanf("%d",&v[i][j]);
		}
	}
	for(i=1;i<=n;i++)	c[i]=-1;
	c[1]=0;
	p1=0;	p2=0;
	q[p1]=1;	nn[p1]=0;
	p1++;
	c[1]=0;
	while(p1!=p2)	{
		n1=q[p2];	c1=nn[p2];
		p2++;
//		printf("n1=%d c1=%d\n",n1,c1);
		for(i=0;i<k[n1];i++)	{
//			printf("v=%d\n",v[n1][i]);
			if(c[v[n1][i]]==-1)	{
				q[p1]=v[n1][i];
				nn[p1]=c1+1;
//				printf("q=%d nn=%d\n",v[n1][i],c1+1);
				p1++;
				c[v[n1][i]]=c1+1;
			}
		}
	}
	for(i=1;i<=n;i++)	printf("%d %d\n",i,c[i]);
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
#define whi 0
#define gra 1
#define bla 2
using namespace std;
int n,d[101],color[101];
bool g[101][101];
queue<int> num;
void dft(){
	int a,i,j;
	for(i=1;i<=n;i++){
	color[i]=whi;
		d[i]=-1;
	}
	num.push(1);
	d[1]=0;
	color[1]=gra;
	while(!num.empty()){
		a=num.front();
		num.pop();
		for(int v=1;v<=n;v++){
			if(g[a][v] && color[v]==whi){
				num.push(v);
				color[v]=gra;
				d[v]=d[a]+1;
			}
			color[a]=bla;
		}
	}	
}
main(){
	int u,k,v,i,j;
	cin>>n;
	for(i=1;i<=n;i++){
		for(j=1;j<=n;j++)
		g[i][v]=false;
	}
	for(i=1;i<=n;i++){
	cin>>u>>k;
		for(j=1;j<=k;j++){
		cin>>v;
			g[u][v]=true;
		}
	}
	dft();
	for(i=1;i<=n;i++)
	cout<<i<<" "<<d[i]<<endl;
	return 0;
}