Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

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

// 頂点s+1から出発する場合の幅優先探索
void bfs(int s, int n, vector<vector<int>>& M, vector<int>& d) {
    static const int INFTY = (1 << 21);

    // 今回は標準ライブラリのキューを使う
    queue<int> q;

    // 各種初期化処理
    // 出発する頂点をpush
    q.push(s);
    // 距離格納配列の初期化
    for (int i = 0; i < n; i++) {
        d[i] = INFTY;
    }
    // 出発点の距離は0
    d[s] = 0;

    // 探索開始
    int u;
    while (!q.empty()) {
        // 先頭を取り出してpopする(訪問)
        u = q.front();
        q.pop();

        // 隣接する訪問可能な頂点をpushする
        for (int v = 0; v < n; v++) {
            if (M[u][v] == 0) continue; //訪問不可
            if (d[v] != INFTY) continue; //訪問済み

            d[v] = d[u] + 1; //今回リンクのコストは1固定
            q.push(v);
        }
    }

    // 頂点1から各頂点までの距離を出力
    // INFTYが入っていた場合は到達不可能なので-1を出力
    for (int i = 0; i < n; i++) {
        cout << i + 1 << " " << ((d[i] == INFTY) ? (-1) : d[i]) << endl;
    }
}


int main() {
    static const int N = 110;
    // n : グラフの頂点数
    // M : 隣接行列(グラフを表現)
    // d : 任意の頂点から各頂点への距離格納配列(INFTYで初期化)
    int n, u, k, v;
    vector<int> d(N);
    vector<vector<int>> M(N, vector<int>(N));

    cin >> n;

    // グラフの初期化
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            M[i][j] = 0;
        }
    }
    // グラフの入力
    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, n, M, d);

    return 0;
}

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

const static int MAX = 100;
int R[MAX][MAX];
int color[MAX], ar[MAX];
int n;

int search(int i){
    std::queue<int> qu;
    if(color[i] == 1){
	return 1;
    }
    qu.push(i);
    color[i] = 1;
    ar[i] = 0;
    while(!qu.empty()){
	int cur = qu.front();
	int flag = 0;
	for(int j = 0; j < n; j++){
	    if(R[cur][j] == 1 && color[j] == 0){
		qu.push(j);
		color[j] = 1;
		ar[j] = ar[cur] + 1;
		flag = 1;
	    }
	}
	if(flag == 0){
	    qu.pop();
	}
    }
    return 0;
}

int main(void){
    int u, k, v;
    std::cin >> n;

    for(int i = 0; i < MAX; i++){
	for(int j = 0; j < MAX; j++){
	    R[i][j] = 0;
	}
    }

    for(int i = 0; i < MAX; i++){
	color[i] = 0;
    }

    for(int i = 0; i < n; i++){
	std::cin >> u >> k;
	u--;
	for(int j = 0; j < k; j++){
	    std::cin >> v;
	    v--;
	    R[u][v] = 1;
	}
    }

    search(0);

    for(int i = 0; i < n; i++){
	if(color[i] == 0){
	    std::cout << i + 1 << " " << -1 << std::endl;
	}else{
	    std::cout << i + 1 << " " << ar[i] << std::endl;
	}
    }

    return 0;
}

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

int main(){
  vector<int> G[100];
  queue<int> q;
  vector<int> d(100,200000000);
  int n,u,k,v,depth;
  bool flg;
  
  cin >> n;
  for (int i=0;i<n;i++){
    cin >> u>> k;
    for (int j=0;j<k;j++){
      cin >> v;
      G[u-1].push_back(v-1);
    }
  }
  for (int vi=0;vi<n;vi++){
    if (d[vi]<=1000)continue;
    depth=0;
    q.push(vi);
    d[vi]=depth;
    while (!q.empty()){
      u=q.front();
      for (int i=0;i<G[u].size();i++){
	v=G[u][i];
	if (d[v]>d[u]+1){
	  q.push(v);
	  d[v]=d[u]+1;
	  flg=true;
	  break;
	}
      }
      if (!flg){
	q.pop();
      }else{
	flg=false;
      }
    }
    
  }
  for (int i=0;i<n;i++)
    cout << i+1 <<" "<< d[i]<<" "<<endl;
  
  return 0;
}

C++: #include<bits/stdc++.h>

using namespace std;

#define rep(a, b) for(int i = a; i <= b; i++)
#define mst(a) memset(a, 0, sizeof(a))
#define mem(a, p) memset(a, p, sizeof(a))

const int MAX = 1e2 + 10;


bool mtx[MAX][MAX];
int vis[MAX];
int n;

queue<int> q;

void init(void)
{
	while(!q.empty())
		q.pop();
	mem(vis, -1);
	return;
}

bool check(int x, int y)
{
	if(mtx[x][y] && vis[y] == -1)
		return true;
	return false;
}

void Bfs(void)
{
	int cnt = 1;
	q.push(1);
	vis[1] = 0;
	while(!q.empty())
	{
		int cur = q.front();
		q.pop();
		rep(1, n)
		{
			if(check(cur, i))
			{
				q.push(i);
				vis[i] = vis[cur] + 1;
				cnt++;
				if(cnt == n)
					return;
			}
		}
	}
	return;
}

int main()
{
	while(~scanf("%d", &n))
	{
		init();
		rep(1, n)
		{
			int row;
			scanf("%d", &row);
			int num;
			scanf("%d", &num);
			while(num--)
			{
				int tmp;
				scanf("%d", &tmp);
				mtx[row][tmp] = true;
			}
		}
		
		Bfs();
		
		rep(1, n)
			printf("%d %d\n", i, vis[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(){
    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<stdio.h>
 
 
int G[101][101], q1[101], q2[101], n;
 
void f(int a, int b){
  int i;
  q1[a] = b;
  for(i = 1; i <= B[a]; i++){
    if(b + 1 < q1[G[a][i]]) f(G[a][i], b + 1);
  }
}
 
int main(){
  int i, j, m;
 
  scanf("%d", &n);
 
  for(i = 1; i <= n; i++){
    q1[i] = 100000000;
    scanf("%d", &m);
    scanf("%d", &q2[m]);
 
    for(j = 1; j <= q2[m]; j++) scanf("%d", &G[m][j]);
  }
 
  f(1, 0);
 
  for(i = 1; i <= n; i++){
    if(q1[i] == 100000000) q1[i] = -1;
  }
 
  for(i = 1; i <= n; i++) printf("%d %d\n", i, q1[i]);
 
  return 0;
}