Go: package main

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

const MAX = 1000
const NIL = -1

type Node struct {
	id    int
	depth int
}

type Queue struct {
	head      int
	tail      int
	container [MAX]Node
}

func (q *Queue) inQueue(x Node) {
	q.container[q.tail] = x
	q.tail = (q.tail + 1) % MAX
}

func (q *Queue) deQueue() Node {
	x := q.container[q.head]
	q.head = (q.head + 1) % MAX
	return x
}

func (q *Queue) isEmpty() bool {
	return q.head == q.tail
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()
	route := make([][]int, n)
	for i := range route {
		u, k := scanInt(), scanInt()
		u--
		route[u] = make([]int, k)
		for j := range route[u] {
			num := scanInt()
			num--
			route[i][j] = num
		}
	}

	d := make([]int, n)
	for i := range d {
		d[i] = NIL
	}

	start := Node{0, 0}
	que := Queue{}
	que.inQueue(start)
	for !que.isEmpty() {
		node := que.deQueue()
		if d[node.id] != NIL {
			continue
		}
		d[node.id] = node.depth

		for _, nextId := range route[node.id] {
			next := Node{id: nextId, depth: node.depth + 1}
			que.inQueue(next)
		}
	}

	for i, depth := range d {
		fmt.Println(i+1, depth)
	}
}

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

const int maxn=(1<<21);
int G[110][110];///构造图
int d[110];///该顶点到顶点1的距离
bool vis[110];
int n;

void BFS(){
    queue<int> q;
    q.push(1);
    d[1]=0;
    vis[1]=true;
    while(!q.empty()){
        int top=q.front();
        q.pop();
        //vis[top]=true;
        for(int i=1;i<=n;i++){
            if(G[top][i]&&vis[i]==false){
       //     if(G[top][i]&&d[i]==maxn){
                d[i]=d[top]+1;
                vis[i]=true;
                q.push(i);
            }
        }
    }
}


int main(){
    scanf("%d",&n);
    memset(G,0,sizeof(G));
    memset(vis,0,sizeof(vis));
    fill(d,d+110,maxn);

  //  memset(d,maxn,sizeof(d));
    for(int i=0;i<n;i++){
        int u,k;
        scanf("%d%d",&u,&k);
        for(int j=0;j<k;j++){
            int v;
            scanf("%d",&v);
            G[u][v]=1;
        }
    }

    BFS();
    for(int i=1;i<=n;i++){
        printf("%d %d\n",i,(d[i]==maxn)?(-1):d[i]);
    }
    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<cassert>
#include<cstdio>
#include<queue>

using namespace std;

int N, G[100][100], V[100], D[100];//G:２頂点,V:次数,D:距離

void bfs(int src){
    queue<int> Q;
    Q.push(src);
    fill(D, D + N, -1);
    D[src] = 0;
    while (! Q.empty()){
        int cur = Q.front();
        Q.pop();
        cerr << cur+1 << " " << D[cur] << endl;
        for (int k = 0; k < N; k++){
            if (G[cur][k] == 1 && D[k] <= D[cur]){
                D[k] = D[cur]+1;
                Q.push(k);
            }
        }
    }
}

int main(){
	scanf("%d", &N);
		int id, c;
		for (int i = 0; i < N; i++){
			scanf("%d", &id); id--;//配列は0から始まるので、頂点番号を-1して考える。
			scanf("%d", V + id);
			for (int j = 0; j < V[id]; j++){
				scanf("%d", &c); c--;//配列は0から始まるので、頂点番号を-1して考える。
				G[id][c] = 1;
			}
		}//データの読み込み完了。
    bfs(0);
}

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

int G[110][110] = {0};
int n;
int D[110] = {0};
void bfs(int src){
 queue<int> Q;
 Q.push(src);
 D[src] = 0;
 while(! Q.empty()){
  int cur = Q.front();
  Q.pop();
  for(int i=1; i<=n; i++){
   if(G[cur][i]==1 && D[i]==0){
    D[i] = D[cur]+1;
    Q.push(i);
   }
  }
 }

 for(int i=1; i<=n; i++){
  if(i!=1 && D[i]==0){
   D[i]=-1;
  }
  cout << i << " " << D[i] << endl;
 }
}

int main(){
 cin >> n;
 int u, k;
 int v[100000];
 for(int i=0; i<n; i++){
  cin >> u >> k;
  for(int j=0; j<k; j++){
   cin >> v[j];
   G[i+1][v[j]] = 1;
  }
 }
 bfs(1);
}

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

typedef long long ll;
typedef pair<ll, ll> P;

#define pb push_back
#define rep(i, n) for(int i = 0; i < (n); i++)
#define FOR(i, a, n) for(int i = a; i < (n); i++)
#define mod (ll)(1e9+7)
#define int ll

static const int N = 100;
static const int no = -1;

__attribute__((constructor))
void initial() {
  cin.tie(0);
  ios::sync_with_stdio(false);
}

ll graph[N][N] = {{}}, d[N] = {}, n;

void bfs(int v) {
  queue<int> q;
  q.push(v);
  ll u;
  for(int i = 1; i <= n; i++) d[i] = no;
  d[v] = 0;
  while(!q.empty()) {
    u = q.front(); q.pop();
    for(int i = 1; i <= n; i++) {
      if((graph[u][i] == 0) || (d[i] != no)) continue;
      d[i] = d[u] + 1;
      q.push(i);
    }
  }
}

signed main() {
	ll u, v, k;
  cin >> n;
  rep(i, n) {
    cin >> u >> k;
    rep(j, k) {
      cin >> v;
      graph[u][v] = 1;
    }
  }

  bfs(1);

  for(int i = 1; i <= n; i++) {
    cout << i << " " << d[i] << endl;
  }

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int dx[8] = {1,0,-1,0,1,-1,-1,1};//右、上、左、下、右上、左上、左下、右下のつもり
int dy[8] = {0,1,0,-1,1,1,-1,-1};//実際は色々反転している。どうせ4か8方向調べるから関係ないとしている。
bool seen[60][60]={true};
int main(void){
    int n;cin >> n;
    vector<vector<int> > x(n+1);
    for(int i=0;i<n;i++){
	int a,b; cin >> a >> b;
	for(int j=0;j<b;j++){
	    int c;cin >> c;
	    x[a].push_back(c);
	}
    }
    
    vector<int> dist(n+1,-1);
    queue<int> que;
    dist[1]=0;que.push(1);
    while(!que.empty()){
	int v = que.front();que.pop();
	for(int i=0;i<x[v].size();i++){
	    if(dist[x[v][i]]!=-1) continue;
	    dist[x[v][i]] = dist[v] + 1; 
	    que.push(x[v][i]);
	}
    }
    for(int i=1;i<=n;i++){
	cout << i << " " << dist[i] << endl;
    }
    return 0;
}

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

int D[100];
int a[100][100];

int main() {
  for (int i = 0; i < 100; i++){
    for (int j = 0; j < 100; j++){
	  a[i][j] = 0;
	  }
	 }
	int n,u,k,v;
	cin >> n;
	for (int i = 0; i < n; i++) {
	  cin >> u >> k;
	  for (int j = 0; j < k; j++) {
	    cin >> v;
		a[u][v] = 1;
		}
	  }
queue<int> Q; //整数を管理するキューの定義
  for (int i = 1; i < n+1; i++){
   D[i] = -1;
   }
  int src = 1;
  Q.push(src);
  D[src] = 0; //出発点
  while (! Q.empty()) {
    int cur = Q.front(); //先頭要素を取り出す
	Q.pop();
	for(int dst = 1 ; dst <= n; dst++) { //各行き先dstに対して
	if((a[cur][dst] == 1 && D[dst] == -1)) { //curからdstに辺があり、dstが未訪問なら
	      D[dst] = D[cur] + 1; //
		    Q.push(dst); //dstを訪問先に入れる
			}
		  }
		}
	for (int i=1; i < n+1; i++){
	  cout << i << " " << D[i] << endl;
	  }
	}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<utility>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<functional>
#include<math.h>
using namespace std;
#define N (1000000000+7)
#define M (998244353)
#define INF 1e16
typedef long long ll;
typedef pair<ll,ll> P;


int g[105][105];
int dist[105]={-1};
bool visit[105];

int main(void){
    int n;
    cin>>n;
    for(int i=0;i<105;i++)dist[i]=-1;
    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][v]=1;
        }
    }
    queue<int>que;
    que.push(1);
    dist[1]=0;
    visit[1]=true;
    while(!que.empty()){
        int now = que.front();
        que.pop();
        for(int i=1;i<=n;i++){
            if(i==now)continue;
            if(visit[i])continue;
            if(g[now][i]){
                dist[i]=dist[now]+1;
                que.push(i);
                visit[i]=true;
            }
        }
    }
    for(int i=1;i<=n;i++)cout<<i<<" "<<dist[i]<<endl;
    return 0;
}