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<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<climits>
#include<iostream>
#include<sstream>
#include<utility>
#include<map>
#include<vector>
#include<queue>
#include<algorithm>
#include<set>
#include<stack>

using namespace std;

const int MAX_N = 101;
const int DUMMY = 10000;

int N, u, k, v = 0;

vector<int>V [MAX_N];
int d [MAX_N];
bool visited [MAX_N];

bool bfs(int u, int depth)
{
    for (int i = 0; i < V[u].size(); ++i) {
        if(V[u][i] == 1) continue;
        bfs(V[u][i] - 1, depth + 1);
    }
        
    
    d[u] = min(d[u], depth);
    
    if (V[u].size() == 0 || u == 0)
        return true;
}

int main()
{
    //initialize
    for (int i = 0; i < MAX_N; ++i) {
        d[i]   = DUMMY;
        visited[i] = false;
    }
    
    //input
    scanf("%d", &N);
    for (int i = 0; i < N; ++i) {
      scanf("%d %d", &u, &k);
      for (int j = 0; j < k; ++j) {
          scanf("%d", &v);
          V[i].push_back(v);
      }
      sort(V[i].begin(), V[i].end());
    }

    //serach
    bfs(1-1, 0);
    
    //output
    for (int i = 0; i < N; ++i) {
      if(d[i] == DUMMY) cout << i+1 << ' ' << -1 << endl;
      else cout << i+1 << ' ' << d[i] << endl;
    }

    return 0;
}

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() {

  cin >> n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }

  int u, k, v;
  for (int i = 0; i < n; i++) {
    cin >> u >> k;
    u--; // to 0 origin
    for (int j = 0; j < n; j++) {
      cin >> v;
      v--; // to 0 origin
      M[u][v] = 1;
    }
  }

  bfs(0);

  return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
static const int N = 100;

int n;
int M[N][N];
int vis[N];
int seq[N];

void bfs_print() {
	for (int i = 0; i < n; i++) {
		cout << i + 1 << ' ' << seq[i]<<endl;
	}
}

int main() {
	cin >> n;
	int u, k;
	int index;

	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;
		for (int j = 0; j < k; j++) {
			cin >> index;
			M[u - 1][index - 1] = 1;
		}
	}
	for (int i = 0; i < n; i++) {
		seq[i] = 0;
		vis[i] = 0;
		if(i >0) seq[i] = -1;
	}

	queue<int> q;
	seq[0] = 0;
	int t;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (M[i][j] == 1) {
				q.push(j);
			}
		}
		while (not q.empty()) {
			if (vis[q.front()] == 0) {
				seq[q.front()] = seq[i] + 1;
				vis[q.front()] = 1;
			}
			q.pop();
		}
	}

	bfs_print();
}
//
//void dfs_visit(int u) {
//	color[u] = GRAY;
//	d[u] = ++tt;
//	for (int v = 0; v < n; v++) {
//		if (M[u][v] == 1 && color[v] == WHITE) {
//			dfs_visit(v);
//		}
//	}
//	color[u] = BLACK;
//	f[u] = ++tt;
//}
//
//void dfs_print() {
//	for (int i = 0; i < n; i++) color[i] = WHITE;
//	tt = 0;
//	for (int i = 0; i < n; i++) {
//		if (color[i] == WHITE) {
//			dfs_visit(i);
//		}
//	}
//
//	for (int i = 0; i < n; i++) {
//		cout << i + 1 << ' ' << d[i] << ' ' << f[i] << endl;
//	}
//}
//

C++: #include <iostream>
#include <cstring>

using namespace std;

int adja[101][101], dist[101];

void bfs() {
    int que[100], l = 0, d = 1;
    que[0] = 1;l++;
    while (l > 0) {
        int temp[100], m = 0;
        for (int i = 0; i < l; ++i) {
            int u = que[i];
            if (0 < dist[u] && dist[u] <= d)
                continue;
            dist[u] = d;
            for (int j = 0, v; (v = adja[u][j]) > 0; j++) {
                temp[m++] = v;
            }
        }
        memcpy(que, temp, sizeof(int) * m);
        l = m;
        d++;
    }
}

int main() {
    int n, k, u;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> u >> k;
        for (int j = 0; j < k; ++j) {
            cin >> adja[u][j];
        }
    }
    bfs();
    for (int i = 1; i <= n; ++i) {
        cout << i << " " << dist[i] - 1 << endl;
    }

    return 0;
}