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 <bits/stdc++.h>
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;
};

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

using namespace std;
const int N = 100;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
const int INFTY = (1<<21);

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

    bfs(0);

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long

const int N = 1000;
vector< vector<int> > G(N);
int d[N],visited[N];

void bfs(){

  fill(d+2,d+N,N);
  queue<pair<int,int>> q;
  q.push({1,1});
  while(!q.empty()){
    auto p = q.front(); q.pop();
    int s = p.first;
    int cnt = p.second;
    for(int i = 0; i < G[s].size(); i++){
      int v = G[s][i];
      d[v] = min(d[v],cnt);
      if(!visited[v]) q.push({v,cnt+1});
      visited[v] = 1;
    }
  }
}

signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n; cin >> 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;
      G[u].push_back(v);
    }
  }

  bfs();
  for(int i = 1; i <= n; i++){
    if(d[i] != N) cout << i << " " << d[i] << endl;
    else cout << i << " " << -1 << endl;
  }

  return 0;
}

C++: #include <stdio.h>
#define MAX 101

int A[MAX][MAX], s[MAX], h[MAX];

void serch(int x, int y){
  int i;
  h[x] = y;
  for(i=1; i<=s[x]; i++){
    if(h[A[x][i]] > y)
      serch(A[x][i], y+1);
  }
}

int main(){
  int i, j, k, n;
  
  scanf("%d", &n);
  for(i=1; i<=n; i++){
    h[i] = 10000;
    for(j=1; j<=n; j++)
      A[i][j] = 0;
  }
  
  for(i=1; i<=n; i++){
    scanf("%d", &k);
    scanf("%d", &s[k]);
    for(j=1; j<=s[k]; j++)
      scanf("%d", &A[k][j]);
  }
  
  serch(1,0);
  
  for(i=1; i<=n; i++){
    if(h[i] == 10000)
      h[i] = -1;
    printf("%d %d\n", i, h[i]);
  }
  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(void) {
  int u, k, v;
  cin >> n;
  //init
  for(int i = 0; i < n; i++) {
    for(int j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }


  //??£??\???????????¨??????0-origin?????£??\???????????????
  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;
}