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 <sstream>
#include <cstdio>
#include <stdlib.h>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
#define max 101
#define INF -1
#define WHITE 0
#define GRAY -1
#define BLACK 1
int n,color[max],d[max];
int varry[max][max];
void bfs(int s){
  queue<int>q;
  int u;
  for(int i=1;i<=n;i++){
    d[i]=INF;
  }
  color[s]=GRAY;
  d[s]=0;
  q.push(s);
  while(!q.empty()){
    u=q.front();
    q.pop();
    for(int i=1;i<varry[u][0]+1;i++){
      if(color[varry[u][i]]==WHITE){
	color[varry[u][i]]=GRAY;
	d[varry[u][i]]=d[u]+1;
	q.push(varry[u][i]);
      }
    }
    color[u]=BLACK;
  }

}
int main(){
  int u;
  cin>>n;
  for(int k=0;k<n;k++){
    cin>>u;
    cin>>varry[u][0];
    for(int i=0;i<varry[u][0];i++)
      cin>>varry[u][i+1];
  }
  bfs(1);
  for(int i=1;i<=n;i++)
    cout<<i<<" "<<d[i]<<endl;


  return 0;
}

C++: // ALDS1_11_C
#include <bits/stdc++.h>
#define endl "\n"
#define rep(i,n) for(int i=0;i<int(n);i++)
#define SZ(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ipair;
template <class T>ostream &operator<<(ostream &o,const vector<T>&v)
{o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}
namespace you {
    std::string to_string(char val) {
        return std::string(1, val);
        // return std::string{val};
        // you::to_string(char)
    }
}

vector<int> d(110,-1);
vector<vector<int>> to(110);
vector<int> setu(110,0);
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(12);

    int n;
    cin>>n;
    rep(i,n){
        int u,k;
        cin>>u>>k;
        setu[u]=k;
        rep(j,k){
            int q;
            cin>>q;
            to[u].emplace_back(q);
        }
    }
    queue<int> next;
    next.push(1);
    d[1]=0;
    while(!next.empty()){
        int cur=next.front();
        next.pop();
        for(int i=0;i<setu[cur];i++){
            int t=to[cur][i];
            //１に近いところから見ているので、もし距離が更新されているならそれ以上距離が短くなることはない。
            //よって、そのnodeからの探索はしなくていい。a⇔bのときに無限ループしちゃう。
            if(d[t]!=-1) continue; 
            d[t]=d[cur]+1;
            next.push(t);
        }
    }
    for(int i=1;i<=n;i++){
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}