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;
#define WHITE 0
#define GRAY 1
#define BLACK 2

int M[101][101];
int d[101];
int searchPos[101];
int color[101];
int n;
queue<int> q;

/*int nextPoint(int curPoint){
    for(int i=searchPos[curPoint];i<n;++i){
        searchPos[curPoint] += 1;
        if(M[curPoint][i]==1 && color[i] == WHITE){
            return i;
        }
    }
    return -1;
}*/

void bfs(int point){
    q.push(point);
    d[point] = 0;
    color[point] = GRAY;
    int cur, next;
    while(q.size()>0){
        cur = q.front();
        q.pop();
        color[cur] = BLACK;
        for(int i=0;i<n;++i){
            if(M[cur][i] != 0 && color[i] == WHITE){
                q.push(i);
                color[i] = GRAY;
                d[i] = d[cur]+1;
            }
        }
    }
}

int main(){
    int u, z, y;
    scanf("%d",&n);
    for(int i=0;i<n;++i){
        searchPos[i] = 0;
        color[i] = WHITE;
        d[i] = 0;
        for(int j=0;j<n;++j){
            M[i][j] = 0;
        }
    }
    for(int i=0;i<n;++i){
        cin >> u >> z;
        for(int j=0;j<z;++j){
            cin >> y;
            M[u-1][y-1] = 1;
        }
    }

    bfs(0);
    for(int i=0;i<n;++i){
        if(color[i]==WHITE){
            // can't reach
            d[i] = -1;
        }
    }
    for(int i=0;i<n;++i){
        printf("%d %d\n",i+1,d[i]);
    }
    return 0;
}

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

const int Max = 100;
const int white = 0;
const int black = 1;
int M[Max][Max];
int d[Max], nt[Max], color[Max];
int n;
queue<int> Q;

int next(int u){
    for(int v=nt[u]; v<n; v++){
        nt[u] = v + 1;
        if(M[u][v]) return v;
    }
    return -1;
}

void bfs_visit(int u){
    for(int i=0; i<n; i++){
        nt[i] = 0;
        d[i] = -1;
    }

    color[u] = black;
    d[u] = 0;
    Q.push(u);
    while(!Q.empty()){
        int u = Q.front();
        int v = next(u);
        if(v != -1){
            if(color[v] == white){
                color[v] = black;
                d[v] = d[u] + 1;
                Q.push(v);
            }
        } else {
            Q.pop();
        }
    }
}

int main(){
    int u, k, v;
    scanf("%d", &n);
    for(int i=0; i<n; i++){
        color[i] = white;
    }
    for(int i=0; i<n; i++){
        cin >> u >> k;
        u--;
        for(int i=0; i<k; i++){
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }

    bfs_visit(0);

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

C++: #include<stdio.h>

int main()
{
  int n, h, i, j, k, l, m, z, flag, Q[100], Z[100];
  int G[100][100];
  scanf("%d", &n);
  
  for(i = 0; i < 100; i++ ) Z[i] = -1;
  
  for( i = 0; i < n; i++){
    scanf("%d", &G[i][0]);
    scanf("%d", &G[i][1]);
    for( j = 2; j < 2 + G[i][1]; j++){
      scanf("%d", &G[i][j]);
    }
  }
  
  m = 0; 
  h = 0; 
  Q[h] = 1;
  z = 0;
  Z[1] = z;
  z++;
  for( i = 0; i < n; i++){
    flag = 0;
    k = Q[m];
    l = G[k - 1][1];
    
    for( j = 0; j < l; j++){
      if( Z[ G[k - 1][2 + j] ] == -1 ){
        h++;
        Q[h] = G[k - 1][2 + j];
        Z[ G[k - 1][2 + j] ] = z;
        flag = 1;
      }
    }
    if( flag == 1 ) z++;
    m++;
    if( Q[m] == 0 ) i = i + n;
  }
  
  for(i = 1; i <= n ; i++){
    printf("%d %d\n", i, Z[i] );
  }
  return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <queue>
#define NUM 100
#define NIL -1
using namespace std;

int V[NUM + 1][NUM + 1];
int dist[NUM + 1];
int node_num;
int t;
int pos;
queue<int> Q;

void init(){
    int V[NUM + 1][NUM + 1];
    for(int i = 1; i <= NUM; i++){
        for(int j = 1; j <= NUM; j++){
            V[i][j] = 0;
        }
    }

    for(int i = 0; i <= NUM; i++) {
        dist[i] = NIL;
    }
    
    t = 0;
}

void get_adj(){
    scanf("%d", &node_num);

    for(int i = 0; i < node_num; i++){
        int num1;
        scanf("%d", &num1);

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

        int num2;
        for(int j = 0; j < n; j++){
            scanf("%d", &num2);
            V[num1][num2] = 1;
        }
    }
}

void touchNextNode(int n){
    printf("before: %d\n", n);
    t += 1;
    for(int i = 1; i <= node_num; i++){
        if(V[n][i] == 1 && dist[i] == NIL){
            printf("i %d\n", i);
            Q.push(i);
            dist[i] = dist[n] + 1;
        }
    }
    Q.pop();
}

void BFS(){
    Q.push(1);
    dist[1] = t;
    touchNextNode(1);
    
    while(Q.size()){
        int pos = Q.front();
        touchNextNode(pos);
    }
}

int main(void){
    init();
    get_adj();
    BFS();
    
    for(int i = 1; i <= node_num; i++){
        printf("%d %d\n", i, dist[i]);
    }

}