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>
using namespace std;

int main(){

  bool adj[100][100];
  int d[100];
  int n,u,v,k;

  cin >> n;
  for (int i=0; i<n; i++){
    cin >> u >> k;
    for (int j=0; j<k; j++){
      cin >> v;
      adj[u-1][v-1] = true;
    }
  }
  
  queue<int> q;
  bool pushed[100];
  q.push(1);
  pushed[1-1] = true;
  d[0] = 0;

  while(q.empty() == false){
    u = q.front();
    q.pop();
    for (int i=0; i<n; i++){
      if (adj[u-1][i]){
	if (pushed[i] != true){
	  d[i] = d[u-1] + 1;
	  q.push(i+1);
	  pushed[i] = true;
	}
      }
    }
  }
  
  cout << 1 << " " << 0 << endl;
  for (int i=1; i<n; i++){
    if (d[i] == 0)
      cout << i+1 << " " << -1 << endl;
    else
      cout << i+1 << " " << d[i] << endl;      
  }

}

C++: #include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <complex>
#include <stack>
#include <queue>
#include <list>
#include <utility>
#include <set>
using namespace std;

int main(){
    int n;
    cin >> n;
    int g[110][110];
    int i, j;
    int u, k, v;
    int dist[110];
    bool visited[110];
    
    for(i = 0; i < n; i++){
        dist[i] = -1;
        for(j = 0; j < n; j++){
            g[i][j] = 0;
        }
    }
    
    for(i = 0; i < n; i++){
        cin >> u >> k;
        u--;
        for(j = 0; j < k; j++){
            cin >> v;
            v--;
            g[u][v] = 1;
        }
    }
    
    queue<int> q1, q2;
    q1.push(0);
    
    for(i = 0; q1.size(); i++){
        while(!q1.empty()){
            int p = q1.front();
            q1.pop();
            
            if(visited[p]) continue;
            visited[p] = true;
            
            dist[p] = i;
            
            for(j = 0; j < n; j++){
                if(g[p][j]){
                    q2.push(j);
                }
            }
        }
        q1 = q2;
        while(!q2.empty()){
            q2.pop();
        }
    }
    
    for(i = 0; i < n; i++){
        printf("%d %d\n", i+1, dist[i]);
    }
}

C++: /*
 * c.cc: 
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>

using namespace std;

/* constant */

const int MAX_N = 100;
const int INF = 1 << 30;

/* typedef */

typedef vector<int> vi;
typedef queue<int> qi;

/* global variables */

vi nbrs[MAX_N];
int dists[MAX_N];

/* subroutines */

/* main */

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

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

    for (int j = 0; j < k; j++) {
      int v;
      cin >> v;
      v--;
      nbrs[u].push_back(v);
    }
  }

  for (int i = 0; i < n; i++) dists[i] = INF;
  dists[0] = 0;

  qi q;
  q.push(0);

  while (! q.empty()) {
    int u = q.front(); q.pop();

    int vd = dists[u] + 1;
    vi &nbru = nbrs[u];
    for (vi::iterator vit = nbru.begin(); vit != nbru.end(); vit++) {
      int &v = *vit;
      if (dists[v] > vd) {
	dists[v] = vd;
	q.push(v);
      }
    }
  }

  for (int i = 0; i < n; i++)
    printf("%d %d\n", i + 1, (dists[i] >= INF) ? -1 : dists[i]);

  return 0;
}

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

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

int n, adj[MAX_N][MAX_N];
int d[MAX_N];

void dfs(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(adj[u][v] == 0) continue;
			if(d[v] != INFTY) continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	for(int i = 0; i < n; i++){
		printf("%d %d\n", i + 1, ((d[i] == INFTY) ? (-1) : d[i]));
	}
}

int main(void){
	int u, k, v;
	scanf("%d", &n);
	for(int i = 0; i < n; i++){
		scanf("%d", &u);
		u--;
		scanf("%d", &k);
		for(int j = 0; j < k; j++){
			scanf("%d", &v);
			v--;
			adj[u][v] = 1;
		}
	}

	dfs(0);
	return 0;
}

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

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

    vector<vector<int>> edge(n);
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            edge[i].push_back(--v);
        }
    }

    queue<int> q;
    vector <int> dist(n, n);
    dist[0] = 0;
    q.push(0);

    while (!q.empty()) {
        int cur = q.front();
        q.pop();
        for (int ch : edge[cur]) {
            if (dist[ch] > dist[cur] + 1) {
                dist[ch] = dist[cur] + 1;
                q.push(ch);
            }
        }
    }

    for (int i = 0; i < n; i++) {
        cout << i + 1 << ' ' << (dist[i] == n ? -1 : dist[i]) << '\n';
    }
    return 0;
}