Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

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

const int MAX = 110;
int mat[MAX][MAX];
int dist[MAX], done[MAX];
int n;

void bfs(int s)
{
  int t = 0;
  queue<int> que;
  que.push(s);
  dist[s] = 0;
  while (!que.empty()) {
    int i = que.front(); que.pop();
    if (done[i]) continue;
    done[i] = 1;
    for (int j = 0; j < n; j++) {
      if (mat[i][j]) {
        dist[j] = min(dist[j], dist[i]+1);
        que.push(j);
      }
    }
  }
}

int main()
{
  cin >> n;

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

  fill(dist, dist+MAX, INT_MAX);
  memset(done, 0, sizeof(done));
  bfs(0);
  for (int i = 0; i < n; i++)
    printf("%d %d\n", i+1, (dist[i]==INT_MAX?-1:dist[i]));

  return EXIT_SUCCESS;
}

C++: #include <iostream>
#include <vector>
#include <list>
#include <cstdlib>
#include <climits>

const int MAX_N = 100;

struct Node {
  int v;
  int d;
  bool visited;
};

int main(void) {
  std::cin.tie(0);
  std::ios::sync_with_stdio(false);  

  int n = 0;
  std::cin >> n;

  std::vector<std::vector<int> *> *graph = new std::vector<std::vector<int> *>(n + 1);
  std::vector<struct Node *> *nodes = new std::vector<struct Node *>(n + 1);
  
  for (int i = 1; i <= n; i++) {
    int v = 0;
    std::cin >> v;

    int k = 0;
    std::cin >> k;

    std::vector<int> *neighbors = new std::vector<int>(k);

    for (int j = 0; j < k; j++) {
      int a = 0;
      std::cin >> a;

      neighbors->at(j) = a;
    }

    graph->at(i) = neighbors;

    struct Node *node = (struct Node *) std::malloc(sizeof(struct Node));

    node->v = i;
    node->d = INT_MAX;
    node->visited = false;
    
    nodes->at(v) = node;
  }

  int count = 0;
  int start = 1;

  std::list<int> *stack = new std::list<int>();

  stack->push_back(nodes->at(start)->v);

  while (!stack->empty()) {
    std::vector<int> *newNodes = new std::vector<int>();

    while (!stack->empty()) {    
      int v = stack->front();
      stack->pop_front();

      if (count < nodes->at(v)->d) {
	nodes->at(v)->d = count;
      }
      
      nodes->at(v)->visited = true;
      
      std::vector<int> *neighbors = graph->at(v);

      for (std::vector<int>::iterator iterator = neighbors->begin(); iterator != neighbors->end(); ++iterator) {
	struct Node *node = nodes->at(*iterator);

	if (!node->visited) {
	  newNodes->push_back(node->v);
	}
      }
    }

    for (std::vector<int>::iterator iterator = newNodes->begin(); iterator != newNodes->end(); ++iterator) {
      stack->push_front(*iterator);
    }

    count++;
  }

  for (std::vector<struct Node *>::iterator iterator = nodes->begin() + 1; iterator != nodes->end(); ++iterator) {
    struct Node *node = *iterator;

    if (node->d == INT_MAX) {
      node->d = -1;
    }
        
    std::cout << node->v << " " << node->d << std::endl;
  }
  
  return 0;
}

C++: #include <bits/stdc++.h>
#define ll long long
#define INF 999999999
#define MOD 1000000007

using namespace std;

typedef pair<int,int>P;

const int MAX_N = 100;

vector<int> G[MAX_N];
int d[MAX_N];

int main()
{
	int n;
	cin >> n;
	for(int i=0;i<n;i++){
		int id;
		cin >> id;
		int k;
		cin >> k;
		for(int j=0;j<k;j++){
			int to;
			cin >> to;
			G[id-1].push_back(to-1);
		}
	}
	fill(d,d+n,INF);
	deque<int> bfs;
	bfs.push_back(0);
	d[0] = 0;
	while(!bfs.empty()){
		int v = bfs.front();
		bfs.pop_front();
		for(int i=0;i<G[v].size();i++){
			int to = G[v][i];
			if(d[to] > d[v]+1){
				d[to] = d[v]+1;
				bfs.push_back(to);
			}
		}	
	}
	for(int i=0;i<n;i++){
		if(d[i] == INF){
			d[i] = -1;
		}
		cout << i+1 << " " << d[i] << "\n";
	}
}

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,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;
}