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;

void bfs(int);

static const int Q = 100;
static const int W = (1<<21);

int n,M[Q][Q],d[Q];

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;
}
    

void bfs(int s){
  queue<int> q;
  q.push(s);

  for(int i=0;i<n;i++){
    d[i]=W;
  }
  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]!=W)continue;
      d[v]=d[u]+1;
      q.push(v);
    }
  }

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

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> P;

#define vi vector<int>
#define vl vector<long long>
#define vvi vector< vector<int> >
#define vvl vector< vector<ll> >
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define REPD(i, n) for (int i = (int)(n-1); i >= 0; i--)
#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define FORD(i, a, b) for (int i = (int)(a); i >= (int)(b); i--)
#define INF 1e18
#define MOD 1e9+7

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

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

const int MAX_N = 110;
vector < vector<int> > G;
int d[MAX_N];

void bfs(int s) {
    d[s] = 0;
    queue<int> q;
    q.push(s);
    while (!q.empty()) {
        int u = q.front(); q.pop();
        REP(i, (int)G[u].size()) {
            int v = G[u][i];
            if (d[v] != -1) continue;
            d[v] = d[u]+1;
            q.push(v);
        }
    }
}

int main() {
    int n;
    cin >> n;
    G.resize(n);
    REP(i, n) {
        d[i] = -1;
        int u, k;
        cin >> u >> k;
        --u;
        REP(j, k) {
            int v;
            cin >> v;
            --v;
            G[u].push_back(v);
        }
    }

    bfs(0);
    REP(i, n) {
        cout << i+1 << ' ' << d[i] << endl;
    }
}

C++: #include <cstdio>

#define N 100

int check(int id, int distance, int a[N + 1][N], int count[N], int d[N]){
    if(d[id] != -1 && distance >= d[id]) return d[id];
    d[id] = distance;
    for(int i = 0; i < count[id]; ++i){
        check(a[id][i], distance + 1, a, count, d);
    }
    return d[id];
}

int main(){
    int n;
    std::scanf("%d", &n);

    int a[N + 1][N];
    int d[N + 1];
    int count[N + 1];
    for(int i = 1; i <= n; ++i){
        int id;
        std::scanf("%d", &id);
        std::scanf("%d", &count[id]);
        for(int j = 0; j < count[id]; ++j){
            std::scanf("%d", &a[id][j]);
        }
        d[id] = -1;
    }

    check(1, 0, a, count, d);

    for(int i = 1; i <= n; ++i){
        std::printf("%d %d\n", i, d[i]);
    }

    return 0;
}

C++: /*
 * ALDS1_11_C.cpp
 *
 *  Created on: May 8, 2018
 *      Author: 13743
 */

#include<iostream>
#include<queue>
#include<vector>

using namespace std;

queue<int> Q;
int d[101];

void bfs(vector<int>* a, int rt) {
	Q.push(rt);
	d[rt] = 1;
	while(!Q.empty()) {
		int u = Q.front();
		Q.pop();
		for(int &x:a[u]) {
			if(d[x] == 0) {
				Q.push(x);
				d[x] = d[u] + 1;
			}
		}

	}
}

int main() {
	int n;
	vector<int> adj[101];

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

	bfs(adj, 1);

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

}

C++: //さっさと済ませられるところはさっさと済ましてしまう．ただし注意深く
#include <cstdio>
#include <iostream>
#include <queue>
#define MAX_VERTEXES 100
#define ZERO 0
#define NIL -1

using namespace std;

//think easy make easy

int n;//num of vertexes(頂点)
int matrix_graph[MAX_VERTEXES+1+1][MAX_VERTEXES+1+1];//1オリジン
int min_path[MAX_VERTEXES+1+1];


int main(){
	scanf("%d",&n);

	int v_num;
	int k;//v_numの出次数

	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			matrix_graph[i][j] = ZERO;
		}
	}

	for(int i=0;i<n;i++){
		scanf("%d",&v_num);
		scanf("%d",&k);

		for(int j=0;j<k;j++){
			int v_num2;
			scanf("%d",&v_num2);
			matrix_graph[v_num][v_num2] = 1;
		}
	}

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

	int s = 1;
	queue<int> q;
	q.push(1);
	while(!q.empty()){
		s = q.front();
		q.pop();
		for(int i=1;i<=n;i++){
			if(min_path[i] == NIL && matrix_graph[s][i] == 1){
				q.push(i);
				min_path[i] = min_path[s] + 1;
			}
		}
	}
	for(int i=1;i<=n;i++){
		cout <<i <<" " <<min_path[i] <<endl;
	}

	return 0;
}