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 <algorithm>
#include <climits>
#include <functional>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;

typedef pair<int, int> i_i;
struct edge { int v, w; };

int INF = INT_MAX / 2;

vector<int> wfs(int N, vector<vector<int> >& G, int s) {
	vector<int> d(N, INF); d[s] = 0;
	queue<int> q; q.push(s);
	while (q.size()) {
		int u = q.front(); q.pop();
		for (int v: G[u])
			if (d[v] > d[u] + 1) {
				d[v] = d[u] + 1;
				q.push(v);
			}
	}
	return d;
}

int main() {
	int N; cin >> N;
	vector<vector<int> > G(N);
	for (int i = 0; i < N; i++) {
		int u, k; cin >> u >> k;
		while (k--) {
			int v; cin >> v;
			G[u - 1].push_back(v - 1);
		}
	}
	vector<int> d = wfs(N, G, 0);
	for (int u = 0; u < N; u++) {
		if (d[u] == INF) d[u] = -1;
		cout << u + 1 << ' ' << d[u] << endl;
	}
}

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

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

ll graph[101][101] = {{}}, d[101] = {}, n;

void bfs(int v) {
  queue<int> q;
  q.push(v);
  ll u;
  for(int i = 1; i <= n; i++) d[i] = -1;
  d[v] = 0;
  while(!q.empty()) {
    u = q.front(); q.pop();
    for(int i = 1; i <= n; i++) {
      if(graph[u][i] == 0) continue;
      if(d[i] != -1) 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 <stdio.h>

#define N 100     
#define SUCCESS 1 // 成功
#define FAILURE 0 // 失敗
#define INFTY 1 << 21 // 到達不可能を表す大きな値

int queue[N]; // キューの本体
int queue_head = 0; // データ先頭
int queue_num; // データ個数

int node_num, M[N + 1][N + 1];
int d[N]; // 距離で訪問状態(color)を管理する

int enqueue(int enq_data) // キューにデータを追加する
{
  if (queue_head + queue_num < N) {
    queue[queue_head + queue_num] = enq_data;
    queue_num++;
    return SUCCESS;
  } else {
    return FAILURE;
  }
}

int dequeue(int *deq_data) // キューからデータを取り出す
{
  if (queue_num > 0) {
    *deq_data = queue[queue_head];
    queue_num--;
    queue_head++;
    return SUCCESS;
  } else {
    return FAILURE;
  }
}

void bfs(int s) {
  enqueue(s); // 始点をキューに入れる
  for (int i = 1; i <= node_num; i++) d[i] = INFTY; // とりあえず全部INFTYにする
  d[s] = 0; // 始点から自分自身までの距離は0
  int u, p;
  while(queue_num > 0) { // キューが空でない間繰り返す
    u = queue[queue_head]; // キューの先頭からノードを取り出し，訪問
    dequeue(&p); // 同上
    for (int v = 1; v <= node_num; v++) {
        if (M[u][v] == 0) continue; // キュー先頭のノードとvが繋がってないならこのループは終了
        if (d[v] != INFTY) continue; // 既に距離を決めているならこのループは終了
        d[v] = d[u] + 1; // 次に訪問するノードまでの距離は，それまでの距離+1
        enqueue(v); // uに繋がっているノードは将来訪問しないといけない
    }
  }
  for (int i = 1; i <= node_num; i++) { // 表示部
    if (d[i] == INFTY) d[i] = -1;
    printf("%d %d\n", i, d[i]);
  }
}

// mainの流れはdfsと同じ(隣接行列の初期化→隣接行列にノード間の接続関係を登録→bfsを呼び出す)
int main(void)
{
  int u, v, k, i, j;
  
  scanf("%d", &node_num);
  for (i = 0; i <= node_num; i++) {
    for(j = 0; j <= node_num; j++) M[i][j] = 0;
  }

  for (i = 0; i < node_num; i++) {
    scanf("%d %d", &u, &k);
    for (j = 0; j < k; j++) {
      scanf("%d", &v);
      M[u][v] = 1;
    }
  }

  bfs(1);
  
  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){ //幅優先探索
	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, k;

	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 i = 0; i < k; i++) {
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}


	bfs(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]; // 距離で訪問状態 (color) を管理する

void bfs(int s) {
	queue<int> q; // 標準ライブラリの queue を使用
	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 <bits/stdc++.h>
using namespace std;
#define WHITE 0
#define GRAY 1
#define BLACK 2

int M[101][101];
int d[101];
int searchPos[101];
int color[101];
int n;
queue<int> q;

/*int nextPoint(int curPoint){
    for(int i=searchPos[curPoint];i<n;++i){
        searchPos[curPoint] += 1;
        if(M[curPoint][i]==1 && color[i] == WHITE){
            return i;
        }
    }
    return -1;
}*/

void bfs(int point){
    q.push(point);
    d[point] = 0;
    color[point] = GRAY;
    int cur, next;
    while(q.size()>0){
        cur = q.front();
        q.pop();
        color[cur] = BLACK;
        for(int i=0;i<n;++i){
            if(M[cur][i] != 0 && color[i] == WHITE){
                q.push(i);
                color[i] = GRAY;
                d[i] = d[cur]+1;
            }
        }
    }
}

int main(){
    int u, z, y;
    scanf("%d",&n);
    for(int i=0;i<n;++i){
        searchPos[i] = 0;
        color[i] = WHITE;
        d[i] = 0;
        for(int j=0;j<n;++j){
            M[i][j] = 0;
        }
    }
    for(int i=0;i<n;++i){
        cin >> u >> z;
        for(int j=0;j<z;++j){
            cin >> y;
            M[u-1][y-1] = 1;
        }
    }

    bfs(0);
    for(int i=0;i<n;++i){
        if(color[i]==WHITE){
            // can't reach
            d[i] = -1;
        }
    }
    for(int i=0;i<n;++i){
        printf("%d %d\n",i+1,d[i]);
    }
    return 0;
}