Go: package main

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

type Queue []int

func (q *Queue) push(v int) {
	*q = append(*q, v)
}

func (q *Queue) pop() int {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	nVerts := scanInt(sc)
	graph := make([][]int, nVerts+1)

	for i := 0; i < nVerts; i++ {
		u := scanInt(sc)
		nDegrees := scanInt(sc)

		graph[u] = make([]int, nDegrees)
		for d := 0; d < nDegrees; d++ {
			graph[u][d] = scanInt(sc)
		}
	}

	paths := make([]int, nVerts+1)

	queue := Queue(make([]int, 0))
	queue.push(1)

	paths[1] = 1
	d := 2
	for len(queue) > 0 {
		u := queue.pop()

		pushed := false
		for _, v := range graph[u] {
			if paths[v] == 0 {
				paths[v] = d
				queue.push(v)
				pushed = true
			}
		}
		if pushed {
			d += 1
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= nVerts; i++ {
		fmt.Fprintf(w, "%d %d\n", i, paths[i]-1)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

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][N];
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 <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll,ll> pl;
typedef vector<pl> vp;
#define fore(i,a,b) for(ll i=(a);i<=(b);++i)
#define rep(i,n) fore(i,0,(n)-1)
#define rfore(i,a,b) for(ll i=(b);i>=(a);--i)
#define rrep(i,n) rfore(i,0,(n)-1)
#define all(x) (x).begin(),(x).end()
const ll INF=1001001001;
const ll LINF=1001001001001001001;
const ll D4[]={0,1,0,-1,0};
const ll D8[]={0,1,1,0,-1,-1,1,-1,0};
template<class T>
bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>
bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
template<class T>
ll sum(const T& a){return accumulate(all(a),0LL);}

ll n;
vl g[105];
void solve(){
    cin>>n;
    rep(i,n){
        ll from,m;cin>>from>>m;from--;
        rep(j,m){
            ll to;cin>>to;to--;
            g[from].push_back(to);
        }
    }
    queue<ll> q;
    q.push(0);
    vl a(n,-1);a[0]=0;
    while(!q.empty()){
        ll from=q.front();q.pop();
        if(!g[from].size())continue;
        rep(i,g[from].size()){
            ll to=g[from][i];
            if(a[to]==-1){
                a[to]=a[from]+1;
                q.push(to);
            }
        }
    }
    rep(i,n){
        cout<<(i+1)<<" "<<a[i]<<endl;
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    solve();
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
#include<sstream>
#include<iterator>
#include<list>
using namespace std;
typedef  long long int lint;
//typedef pair<int, int> IP;
typedef pair<lint, lint> LLP;
typedef pair<char, char>CP;
#define rep(i, n) for (int i = 0; i < n; i++)
#define repr(i, n) for (int i = n; i >= 0; i--)
#define sort(v) sort((v).begin(), (v).end())
#define reverse(v) reverse((v).begin(), (v).end())
#define upper(v,hoge) upper_bound(v.begin(),v.end(),hoge)
#define lower(v,hoge) lower_bound(v.begin(),v.end(),hoge)
#define llower(v,hoge) *lower_bound(v.begin(), v.end(), hoge)
#define lupper(v,hoge) *upper_bound(v.begin(), v.end(), hoge)
#define mp make_pair
#define P pair<int,int>
int main() {
	int INF = 10000000;
	int V;
	cin >> V;
	vector<vector<int>>G(V);
	rep(i, V) {
		int v, k;
		cin >> v >> k;
		v--;
		rep(j, k) {
			int tmp;
			cin >> tmp;
			tmp--;
			G[v].push_back(tmp);
		}
	}
	int start = 0;//スタート位置

	vector<int>dist(V, INF);//startからの距離を入れる配列。INF(未訪問)で初期化
	queue<int> que;

	dist[start] = 0;
	que.push(start);

	//BFS
	while (!que.empty()) {
		int v = que.front();
		que.pop();

		for (int nv : G[v]) {
			if (dist[nv] != INF)continue;
			dist[nv] = dist[v] + 1;
			que.push(nv);
		}
	}
	rep(i, V) {
		if (dist[i] == INF) {
			cout << i + 1 << ' ' << -1 << endl;
		}
		else {
			cout << i + 1 << ' ' << dist[i] << endl;
		}
	}
}

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


#define show(x) #x " = " << x

int n;
vector<int> G[100];
int d[100];

int main() {
	int i;
	cin >> n;
	for ( i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for( i = 0; i < k; i++) cin >> v, G[u - 1].push_back(v - 1);
	}
	for (i = 0; i < 100; i++) d[i] = -1;

	queue<int> q;
	q.push(0);
	d[0] = 0;
	while (!q.empty()) {
		int v = q.front(); q.pop();
		for (int i = 0; i < G[v].size(); i++) {
			int x = G[v][i];
			if (d[x] == -1) {
				d[x] = d[v] + 1;
				q.push(x);
			}
		}
	}
	for (i = 0; i < n; i++) cout << i + 1 << " " << d[i] << endl;

}

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

#define N_MAX 100
#define WH 0
#define BK 2


long n;
long G[N_MAX][N_MAX] = {};
long color[N_MAX] = {};
long dist[N_MAX];
queue<long> Q;

void bfs(long u) {
    Q.push(u);
    color[u] = BK;
    dist[u] = 0;
    while (Q.empty() == false) {
        u = Q.front();
        Q.pop();
        for (long v = 0; v < n; v++) {
            if (G[u][v] == 1 && color[v] == WH) {
                Q.push(v);
                color[v] = BK;
                dist[v] = dist[u] + 1;
            }
        }
    }
}

int main() {
    long v_from, deg_out, v_to;

    cin >> n;
    for (long i = 0; i < n; i++) {
        cin >> v_from >> deg_out;
        v_from--;
        for (long j = 0; j < deg_out; j++) {
            cin >> v_to;
            v_to--;
            G[v_from][v_to] = 1;
        }
    }

    // for (long i = 0; i < n; i++) {
    //     for (long j = 0; j < n; j++) {
    //         if (j != 0) { cout << " "; }
    //         cout << G[i][j];
    //     }
    //     cout << endl;
    // }


    for (long i = 0; i < n; i++) {
        dist[i] = -1;
    }

    bfs(0);

    for (long i = 0; i < n; i++) {
        cout << i + 1 << " " << dist[i] << endl;
    }

    return 0;
}