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;
static const int N = 100;
static const int INFTY = (1<<21);

int n, M[N][N];
int d[N];  // 距離で訪問状態（color）を管理する

void bfs(int s) {
  queue<int> q;  // 標準ライブラリの queue を使用
  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<iostream>
#include<queue>
#include<string>

using namespace std;

void bfs();

const int Infty = 20000000;

bool **M;
int *dist,n;
string *color;
queue<int> Q;

int main(){
	cin>>n;
	M = new bool*[n]; for(int i=0;i<n;i++) M[i] = new bool[n];
	color = new string[n]; dist = new int[n];
	
	for(int i=0;i<n;i++) M[i] = M[i]-1; M = M-1;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++) M[i][j] = false;
	}
	color = color-1; dist = dist-1;

	int vertex,deg,edge;
	for(int i=1;i<=n;i++){
		cin>>vertex>>deg;
		for(int j=1;j<=deg;j++){
			cin>>edge;
			M[vertex][edge] = true;
		}
	}

	bfs();

	for(int i=1;i<=n;i++){
		cout<<i<<" ";
		if(dist[i]!=Infty)
			cout<<dist[i]<<endl;
		else
			cout<<-1<<endl;
	}

	for(int i=1;i<=n;i++) delete [] (M[i]+1); delete [] (M+1);
	delete [] (color+1); delete [] (dist+1);
}

void bfs(){
	for(int i=1;i<=n;i++){
		color[i] = "WHITE"; dist[i] = Infty;
	}

	int s = 1;
	Q.push(s);
	color[s] = "GRAY";
	dist[s] = 0;
	int u;
	while(!Q.empty()){
		u = Q.front();
		Q.pop();
		for(int v=1;v<=n;v++){
			if(M[u][v]==true&&color[v]=="WHITE"){
				Q.push(v);
				color[v] = "GRAY";
				dist[v] = 0;
				dist[v] = dist[u]+1;
			}
		}
		color[u] = "BLACK";
	}
}

C++: #include<bits/stdc++.h>

using namespace std;

#define rep(a, b) for(int i = a; i <= b; i++)
#define mst(a) memset(a, 0, sizeof(a))

const int MAX = 1e2 + 10;


bool mtx[MAX][MAX];
int vis[MAX];
int n;

queue<int> q;

void init(void)
{
	while(!q.empty())
		q.pop();
	mst(vis);
	return;
}

bool check(int x, int y)
{
	if(mtx[x][y] && !vis[y])
		return true;
	return false;
}

void GetAns(void)
{
	rep(2, n)
	{
		if(vis[i] == 0)
			vis[i] = -1;
	}
	return;
}

void Bfs(void)
{
	int cnt = 1;
	q.push(1);
	while(!q.empty())
	{
		int cur = q.front();
		q.pop();
		rep(1, n)
		{
			if(check(cur, i))
			{
				q.push(i);
				vis[i] = vis[cur] + 1;
				cnt++;
				if(cnt == n)
					return;
			}
		}
	}
	return;
}

int main()
{
	while(~scanf("%d", &n))
	{
		init();
		rep(1, n)
		{
			int row;
			scanf("%d", &row);
			int num;
			scanf("%d", &num);
			while(num--)
			{
				int tmp;
				scanf("%d", &tmp);
				mtx[row][tmp] = true;
			}
		}
		
		Bfs();

		GetAns();
		
		rep(1, n)
			printf("%d %d\n", i, vis[i]);
	}
	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <stack>
#include <cstdlib>
#include <queue>
#include <vector>
#include <set>

using namespace std;
int n,m,l,p;
bool a[100][100];
int D[100];
void bfs( int src) {
	queue<int> Q;
	Q.push(src);
	D[src]=0;
	while( ! Q.empty() ) {
		int cur = Q.front();
		Q.pop();
		for(int dst = 0; dst < n; dst++ ) {
			if( D[dst] < 1 && a[cur][dst] == 1 ) {
				D[dst] = D[cur] + 1;
				Q.push(dst);
			}
		}
	}
	for (int i = 0; i < n;i++) {
	cerr << i+1 <<  " " << D[i] <<  endl;
	}
}

int main() {
	cin >> n;
	for ( int i = 0;i < n;i++) {
		D[i] = -1;
		for(int j= 0; j < n;j++) {
			a[i][j] = 0;
		}
	}
	for (int i = 0;i < n; i++){
		cin >> m;
		cin >> l;
		for(int j = 0; j < l;j++) {
			cin >> p;
			a[m-1][p-1] = 1;
		}
	}
	bfs(0);
}

C++: // AOJ
// ALDS1_11_C Breadth First Search
// https://onlinejudge.u-aizu.ac.jp/problems/ALDS1_11_C
#include <bits/stdc++.h>
using namespace std;

typedef vector<int> vi;
typedef vector<vi> vvi;
#define rep(i, n) for(int i = 0; i < (n); i++)

int main()
{
    int n; cin >> n;
    vvi g(n, vi(n, 0));
    rep(i, n) {
        int u, k; cin >> u >> k; u--;
        rep(j, k) {
            int v; cin >> v; v--;
            g[u][v] = 1;
        }
    }

    vi ans(n, -1);
    queue<int> q;
    q.push(0);
    ans[0] = 0;
    while (!q.empty()) {
        int u = q.front(); q.pop();
        rep(i, n) {
            if (g[u][i] == 1 && ans[i] == -1) {
                q.push(i);
                ans[i] = ans[u]+1;
            }
        }
    }

    rep(i, n) cout << i+1 << " " << ans[i] << endl;
}