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 <bits/stdc++.h>

#define REP(i, n) for(int i = 0; i < n; i++)
using namespace std;

int main()
{   
    /* 座席　（中央×後）*/
    //資料の説明通りにやってみたつもりです

    int n;
    cin >> n;
    vector<vector<int>> edges(n, vector<int>());

    REP(i, n) {
        int u, k, e;
        cin >> u >> k;

        REP(j, k) {
            cin >> e;
            edges.at(u-1).push_back(e-1);
        }
    }

    queue<int> Q;
    vector<int> dst(n, 1000000);

    dst[0] = 0;
    Q.push(0);

    while (!Q.empty()) {
        int cur = Q.front();
        Q.pop();

        REP(i, edges[cur].size()) {
            if (dst[edges[cur][i]] == 1000000)
                Q.push(edges[cur][i]);
                if (dst[edges[cur][i]] > dst[cur]+1)
                    dst[edges[cur][i]] = dst[cur]+1;
        }
    }

    REP(i, n) {
        if (dst[i] == 1000000)
            cout << i+1 << " " << -1 << endl;
        else 
            cout << i+1 << " " << dst[i] << endl;
    }
}

C++: #include <iostream>
#include <queue>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;
int m[N][N],color[N],d[N],n;



void bfs(int s){
	
	queue<int> q;
	q.push(s);
	for(int i=0;i<N;i++){
		color[i] = WHITE;
		d[i] = (1<<21);
	}
	d[s] = 0;
	color[s] = GRAY;
	int u;
	while(!q.empty()){
		u = q.front();
		q.pop();
		
		for(int v=0;v<n;v++){
			if(m[u][v]&&color[v]==WHITE){
				color[v] = GRAY;
				d[v] = d[u]+1;
				q.push(v);
			}
		}
	}
	for(int i=0;i<n;i++){
			cout<<i+1<<" "<<((d[i]==(1<<21))?(-1):(d[i]))<<endl; 
		}
}
	
	int main(){
		int u,v,k;
		
		cin>>n;
		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 <set>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <ctype.h>
#include <ctime>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <numeric>
#include <complex>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <cassert>
#include <iostream>
#include <iterator>
#include <algorithm>

using namespace std;
#define N 100
#define INF 1e9

queue<int> Q;
int n,M[N][N];
int dist[N];

void bsf(int l){
	Q.push(l);
	for(int i = 0;i < n;i++) dist[i] = INF;

	dist[l]=0;
	while(!Q.empty()){
		int u = Q.front();
		Q.pop();
		for(int i=0;i<n;i++){
			if(M[u][i] == 0)continue;
			if(dist[i] != INF)continue;
			dist[i] = dist[u] + 1;
			Q.push(i);
		}
	}
}

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;
		}
	}
	bsf(0);
	return 0;
}

C++: #include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <cmath>
#include <iomanip>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <deque>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>

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);

}

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

void solve(){
  int n; cin >> n;
  vector<vector<int> > v(n + 1, vector<int>(n + 1, 0));
  for(int i = 0; i < n; i++){
    int u, k; cin >> u >> k;
    for(int j = 0; j < k; j++){
      int x; cin >> x;
      v[u][x] = 1;
    }
  }
  queue<int> q;
  vector<int> ans(n + 1, -1), c(n + 1, 0);
  q.push(1);
  ans[1] = 0;
  c[1] = 1;
  while(q.size() != 0){
    int x = q.front();
    q.pop();
    for(int i = 1; i <= n; i++){
      if(v[x][i] == 1 && c[i] == 0){
        q.push(i);
        ans[i] = ans[x] + 1;
        c[i] = 1;
      }
    }
  }
  for(int i = 1; i <= n; i++){
    cout << i << " " << ans[i] << endl;
  }
  return;
}

int main(){
  solve();
  return 0;
}

C++: #include<iostream>
#include<cstdio>
#define INF 1<<30
#define MAX 100000
using namespace std;

class Queue{
private:
  int inf[MAX];
  int head,tail;
 
public:
 
  Queue(){
    syokika();
  }
 
  void syokika(){
    head = 0;
    tail = 0;
  }
 
  void push(int x){
    inf[tail]=x;
    if(MAX == tail+1)tail = 0;
    else tail++;
  }
 
  void pop(){
    if(MAX == head+1)head=0;
    else head++;
  }
 
  int front(){
    return inf[head];
  }
 
  bool empty(){
    if(tail - head == 0)return true;
    else return false;
  }
 
  int size(){
    return tail - head;
  }
 
};

int imap[200][200];
int k[200] = {0}; 
int ans[200] = {0};
bool used[200];

int main(){
  int n,u[1000];
  cin >> n;
  for(int i=0;i<200;i++)for(int j=0;j<200;j++)imap[j][i] = INF;  
  for(int i=0;i<n;i++){
    cin >> u[i];
    cin >> k[u[i]];
    for(int j=0;j<k[u[i]];j++){
      cin >> imap[u[i]][j];
    }
  }

   int h;
  for(int i=0;i<n;i++){
    int Min = i;
    for(int j=i;j<n;j++){
      if(u[Min] > u[j])Min = j; 
    }
    h = u[Min];
    u[Min] = u[i];
    u[i] = h;
  }

  Queue que = Queue();

  que.push(u[0]);

  while(!que.empty()){
    int p = que.front(); que.pop();
    for(int i=0;i<k[p];i++){
      if(!used[imap[p][i]]){
	que.push(imap[p][i]);//cout << "push!= " << imap[p][i] << endl;
	used[imap[p][i]] = true;
	ans[imap[p][i]] = ans[p] + 1;
      }
    }
  }
  //for(int i=0;i<n;i++)cout << u[i] << endl;
 
  for(int i=0;i<n;i++){
    cout << u[i]-1 << " " << ans[u[i]] << endl;
  }

  return 0;
}