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;
int i,j,n,u,k,v,g[101][101],d[101],f[101];
int main(void){
  for(i=1;i<101;i++)d[i]=1<<30;
  d[1]=0;
  cin>>n;
  for(i=0;i<n;i++){
    cin>>u>>k;
    for(j=0;j<k;j++){
      cin>>v;
      g[u][v]++;
    }
  }
  queue<int>q;
  q.push(1);
  while(!q.empty()){
    u=q.front();q.pop();
    f[u]=1;
    for(i=1;i<101;i++){
      if(g[u][i]&&!f[i]){
        d[i]=min(d[i],d[u]+1);
        q.push(i);
      }
    }
  }
  for(i=1;i<=n;i++)cout<<i<<" "<<(d[i]==1<<30?-1:d[i])<<endl;
  return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <queue>

using namespace std;
const int N = 100;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;

int n;
vector<vector<int>> G(N,vector<int>(N,0));
vector<int> d(N,-1);
vector<int> colors(N,WHITE);

void bfs(){
    queue<int> q;
    q.push(0);
    colors[0] = GRAY;
    d[0] = 0;
    while(!q.empty()){
        int u = q.front();q.pop();
        for(int i = 0;i<n;i++){
            if(colors[i]==WHITE && G[u][i]){
                q.push(i);
                colors[i] = GRAY;
                d[i] = d[u] + 1;
            }
        }
        colors[u] = BLACK;
    }
}

int main()
{
    //freopen("data.txt","r",stdin);
    cin >> n;
    int u,k,v;
    for(int i = 0;i<n;i++){
        cin >> u >> k;
        u--;
        for( int j =0;j<k;j++){
            cin >> v;
            v--;
            G[u][v] = 1;
        }
    }
    bfs();
    for(int i =0;i<n;i++){
        printf("%d %d\n",i+1,d[i]);
    }
    return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <vector>
using namespace std;
#define N 105 // number of nodes
vector<int> neighbors[N]; //start from 1

//http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_C bfs
int dist[N];
void bfs(int start, int key,int d){
	if(start == key){
		//if(d < dist[key])
			dist[key] = d;
		return;
	} 
	for(int i = 0; i< neighbors[start].size(); i++){
		bfs(neighbors[start].at(i), key,d+1);
	}
}

int main()
{
    int n;
    scanf("%d",&n);
    memset(dist, -1, sizeof(dist));
    for(int i = 0; i<n; i++){
        int node;
        scanf("%d",&node);
        int num;
        scanf("%d",&num);
        for(int j = 0; j<num; j++){
        	int temp;
        	scanf("%d",&temp);
        	neighbors[node].push_back(temp);
		}
    }
    for(int i = 1; i<=n; i++){
    	bfs(1,i,0);
	}
    for(int i = 1; i<=n; i++){
    	printf("%d %d\n",i, dist[i]);
	}
    return 0;
}

C++: #include<bits/stdc++.h>
#define INF 10000000
using namespace std;

int z[100],n;
int a[100][100];

void bfs(){
  int m;
  z[0]=0;
  queue<int> q;
  q.push(0);
  while(!q.empty()){
    m=q.front();
    q.pop();
    for(int i=0;i<n;i++){
      if(a[m][i]==1){
	q.push(i);
	z[i]=min(z[i],z[m]+1);
      }
    }
  }
}


int main(){
  int p,x;
  for(int i=0;i<100;i++){
    z[i]=INF;
    for(int j=0;j<100;j++) a[i][j]=0;
  }
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>p>>p;
    for(int j=0;j<p;j++){
      cin>>x;
      a[i][x-1]=1;
    }
  }
  bfs();
  for(int i=0;i<n;i++){
    if(z[i]!=INF) cout<<i+1<<" "<<z[i]<<endl;
    else cout<<i+1<<" "<<-1<<endl;
  }
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
static const int INF=(1<<21);
int n,m[101][101];
int d[101];
void bfs(int s){
  queue<int>q;
  q.push(s);
  for(int i=0;i<n;i++){
    d[i]=INF;
  }
  d[s]=0;
  while(!q.empty()){
    int u=q.front();
    q.pop();
    for(int v=0;v<n; v++){
      if(m[u][v]==0){
	continue;
      }
      if(d[v]!=INF){
	continue;
      }
      d[v]=d[u]+1;
      q.push(v);
    }
  }
  for(int i=0;i<n;i++){
    cout<<i+1<<" "<<( (d[i]==INF)?(-1):d[i] )<<endl;
  }
}
int main(){
  int u,k,v;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v;
      m[u-1][v-1]=1;
    }
  }
  bfs(0);
  return(0);
}

C++: #include<cstdio>
#include<vector>
#include<algorithm>
#include<utility>
#include<numeric>
#include<iostream>
#include<array>
#include<string>
#include<sstream>
#include<stack>
#include<queue>
#include<list>
#define _USE_MATH_DEFINES

#include<math.h>
#include<map>

#define SENTINEL 1000000001

#define min(a,b) (a)>(b)?(b):(a)
#define max(a,b) (a)>(b)?(a):(b)

using namespace std;

int G[101][101];
int d[101];

void explore(int id, int n,int cnt)
{
	if (d[id] == -1)
	{
		d[id] = cnt;
	}
	else
	{
		d[id] = min(d[id], cnt);
	}

	for (int i = 1; i <= n; i++)
	{
		if (G[id][i] == 1)
		{
			explore(i, n, cnt + 1);
		}
	}
}

int main()
{
	int n;
	cin >> n;

	for (int i = 0; i < n; i++)
	{
		int id, k;
		cin >> id >> k;

		for (int i = 0; i < k; i++)
		{
			int v;
			cin >> v;
			G[id][v] = 1;
		}
	}

	for (int i = 1; i <= 100; i++)
	{
		d[i] = -1;
	}

	explore(1, n, 0);

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

	return 0;
}