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 <cstdio>
#include <cstring>
#include <queue>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int flag[maxx];
int d[maxx];


void bfs() {
	queue<int>q;

	q.push(1);
	d[1] = 0;
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		for (int i = 2; i <= n; i++) {
			if (m[u][i] == 1 && flag[i] == 0) {
				// ?????°???????????????
				flag[i] = 1;
				// ??´??°??????
				d[i] = d[u] + 1;
				// ?????\??????
				q.push(i);
			}
		}
	}
}
int main()
{

	scanf("%d", &n);
	memset(m, 0, sizeof(m));
	for (int i = 1; i <= n; i++) {
		scanf("%d %d", &u, &num);

		// ????§????
		flag[i] = 0;
		d[i] = -1;
		for (int j = 1; j <= num; j++) {
			scanf("%d", &v);
			m[u][v] = 1;
		}
	}
	bfs();
	for (int i = 1; i <= n; i++) {
		printf("%d %d\n", i, d[i]);
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
const int N = 101;
const int CRL = -1;
int adj[N][N] = {0};
int d[N]={0};
int kai[N];

int main()
{
    int n;
    queue <int> q;
    q.push(1);
    cin >> n;
    for(int i=1;i<=n;i++){
    	int k;
    	int l;
    	cin >> l >> k;
    	kai[i]=l;
    	for(int j=1;j<k+1;j++){
    		int m;
    		cin >> m;
    		adj[i][j] = m;
    	}
    }
    while(q.size()){
    	int k = q.front();
    	q.pop();
    	for(int i=1;i<kai[i]+1;i++){
    		if(d[adj[k][i]]==0){
    			d[adj[k][i]] = d[k]+1;
    			q.push(adj[k][i]);
    		}
    	}
    }
    for(int i=1;i<=n;i++){
    	cout << i << " " << d[i] << endl;
    }
    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,v,k;
    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 < (n); ++i)

using namespace std;
using ll = long long;
using v1 = vector<int>;
using vl = vector<long long>;
using v2 = vector<vector<int>>;
using v3 = vector<vector<char>>;


void bfs(v2& a, v2& b){
	queue<int> q;
	q.push(a[0][0]);
	while(!q.empty()){
		int x = q.front()-1;
		int t = b[x][1];
		q.pop();
		rep(i, a[x][1]){
			int y = a[x][2+i]-1;
			if(a[y][0] != -1 && a[y][0] != -2){
				b[y][1] = t+1;
				a[y][0] = -1;
			}
			if(a[y][0] != -2) q.push(y+1);
		}
		a[x][0] = -2;
	}
}

int main(){
	int n;
	cin >> n;
	v2 a(n, v1(0));
	v2 b(n, v1(2, 0));
	rep(i, n){
		int m;
		cin >>m;
		a[i].push_back(m);
		b[i][0] = m;
		int x;
		cin >> x;
		a.at(i).push_back(x);
		rep(j, x){
			int y;
			cin >> y;
			a.at(i).push_back(y);
		}
	}
	bfs(a, b);
	for(int i = 1;i<n; i++){
		if(b[i][1] == 0) b[i][1] = -1;
	}
	rep(i, n){
		rep(j, 2){
			cout << b[i][j];
			if(j != 1) cout << " ";
			else cout << endl;
		}
	}
}

C++: #include<stdio.h>
#include<queue>
#define MAX 101
using namespace std;

int G[MAX][MAX], d[MAX];
queue<int> Q;

void adjacency_matrices(int n) {
    int i, j, u, m, k;

    for (i=1; i<=n; i++) {
        scanf("%d", &u);
        scanf("%d", &m);
        for (j=1; j<=m; j++) {
            scanf("%d", &k);
            G[u][k] = 1;
        }
    }
}

void breadth_first_search(int n, int i, int dist) {
    int k;
    d[i] = dist++;
    for (int j=1; j<=n; j++) {
        if (G[i][j]==1 && d[j]==-1) {
            Q.push(j);
            d[j] = dist;
        }
    }

    while(!Q.empty()) {
        dist++;
        int length = Q.size();
        for (int j=1; j<=length; j++) {
            k = Q.front(); Q.pop();
            for (int m=1; m<=n; m++) {
                if (G[k][m]==1 && d[m]==-1) {
                    Q.push(m);
                    d[m] = dist;
                }
            }
        }
    }
}

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

    for (int i=1; i<=n; i++) {
        d[i]=-1;
        for (int j=1; j<=n; j++) {
            G[i][j] = 0;
        }
    }

    adjacency_matrices(n);

    breadth_first_search(n, 1, 0);

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