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;
int G[100][100];
int d[100];
int color[100];
int n;
queue<int> qu;
void bfs ()
{
    color[0] = 1;
    d[0] = 0;
    qu.push(0);
    while (!qu.empty())
    { 
        int u = qu.front(); qu.pop();
        for (int i = 0; i < n; i++)
        {
            if (G[u][i] == 1 && color[i] == 0)
            {
                color[i] = 1;
                d[i] = d[u] + 1;
                qu.push(i);
            }
        }
        color[u] = 2;
    } 
    return;
}

int main()
{
    int k, u, v;
    cin>>n;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            G[i][j] = 0; 
        }  
    } 

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

    for (int i = 0; i < n; i++)
    {
        d[i] = -1; 
        color[i] = 0;
    } 
    bfs();
    for (int i = 0; i < n; i++)
    {
         cout<< i+1<<" "<<d[i]<<endl;
    } 
    return 0;
}

C++: #include<bits/stdc++.h>
#define REP(i,n) for(long long i=0;i<n;++i)
#define FOR(i,a,b) for(long long i=a;i<b;++i)
using namespace std;
const int INF=1<<30;
int n,graph[101][101],v[101];
void bfs(int s){
    queue< int > q;
    fill(v,v+101,INF);
    q.push(s);
    v[s]=0;
    while(!q.empty()){
        int p=q.front();q.pop();
        FOR(i,1,n+1){
            if(!graph[p][i]) continue;
            if(v[i]==INF){
                v[i]=v[p]+1;
                q.push(i);
            }
        }
    }
    FOR(i,1,n+1){
        printf("%d ",i);
        printf("%d\n",v[i]!=INF?v[i]:-1);
    }
}
int main(){
    int u,k,e;
    scanf("%d",&n);
    REP(i,n){
        scanf("%d%d",&u,&k);
        REP(j,k){
            scanf("%d",&e);
            graph[u][e]=1;
        }
    }
    bfs(1);
    return 0;
}

C++: #include <cstdio>
#include <iostream>
#include <queue>
using namespace std;

static const int MAX_NUM = 101;

void BFS(int matrix[][MAX_NUM], int num, int target, int result[])
{
    queue<int> Q;
    int  distance = 0;
    char state[MAX_NUM] = {0};

    Q.push(target);
    result[target] = distance;
    state[target] = 1;

    while (Q.empty() == false) {
        int index = Q.front();
        Q.pop();

        for (int i = 1; i < num + 1; i++) {
            if ((matrix[index][i] == 1) && (state[i] == 0)) {
                Q.push(i);
                state[i]  = 1;
                result[i] = result[index] + 1;
            }
        }
    }

    return;
}

int main(void)
{
    int num;
    int index, elemNum, tmp;
    int matrix[MAX_NUM][MAX_NUM] = {0};
    int result[MAX_NUM];

    scanf("%d", &num);
    for (int i = 1; i < num + 1; i++) {
        result[i] = -1;
        scanf("%d %d", &index, &elemNum);
        for (int j = 0; j < elemNum; j++) {
            scanf("%d", &tmp);
            matrix[index][tmp] = 1;
        }
    }

    BFS(matrix, num, 1, result);

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

    return 0;
}

C++: //Breadth First Search (?????????) Algorithm
#include<iostream>
#include<queue>
#define WH 0
#define GR 1
#define BL 2
#define INF 2000000
void bfs(int);
int n, *color, **M, *d;
std::queue<int> Q;
int main(){
  std::cin>>n;
  color=new int[n], d=new int[n], M=new int*[n];
  for(int i=0, u, k;i<n;i++){
    M[i]=new int[n];
    color[i]=WH, d[i]=INF;
    for(int j=0;j<n;j++) M[i][j]=0;
    std::cin>>u>>k;
    for(int j=0, v;j<k;j++){
      std::cin>>v;
      M[u-1][v-1]=1;
    }
  }
  bfs(0);
  for(int i=0;i<n;i++) std::cout<<i+1<<" "<<(d[i]!=INF?d[i]:-1)<<std::endl;
  delete color;
  delete d;
  for(int i=0;i<n;i++) delete M[i];
  delete M;
  return 0;
}

void bfs(int s){
  color[s]=GR, d[s]=0;
  Q.push(s);
  while(!Q.empty()){
    int u=Q.front();
    Q.pop();
    for(int i=0;i<n;i++){
      if(M[u][i]&&color[i]==WH){
        color[i]=GR, d[i]=d[u]+1;
        Q.push(i);
      }
    }
    color[u]=BL;
  }
}

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

using namespace std;

const int N = 100;
bool G[N][N];
int n;
vector<int> d(N, -1);

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

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

    for (int i = 0; i < n; ++i) {
        int u, k;
        scanf("%d %d", &u, &k);
        --u;
        for (int j = 0; j < k; ++j) {
            int v;
            scanf("%d", &v);
            --v;
            G[u][v] = true;
        }
    }
    d[0] = 0;
    bfs(0);
    for (int u = 0; u < n; ++u) {
        cout << u + 1 << " " << d[u] << endl;
    }
}