Go: package main

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

type Pair struct {
	v int
	d int
}

type Queue []Pair

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

func (q *Queue) pop() Pair {
	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([]Pair, 0))
	queue.push(Pair{1, 1})
	paths[1] = 1

	for len(queue) > 0 {
		p := queue.pop()
		d := p.d + 1
		for _, v := range graph[p.v] {
			if paths[v] == 0 {
				paths[v] = d
				queue.push(Pair{v, d})
			}
		}
	}

	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<bits/stdc++.h>
using namespace std;
const int MAXN = 100+7;
int m[MAXN][MAXN];
queue<int> q;
int d[MAXN];
bool v[MAXN];
int n;
void bfs(int start) {
    d[start] = 0;
    v[start] = true;
    q.push(start);
    int u = 1;
    while(!q.empty()) {
        int x = q.front();
        int i;
        for(i = 1; i <= n; i++) {
            if(m[x][i]==1 && v[i] == false) {
                v[i] = true;
                d[i] = d[x]+1;
                q.push(i);
            }
        }
        q.pop();
    }
}
int main() {
    scanf("%d", &n);
    memset(m, 0, sizeof(m));
    memset(d, -1, sizeof(d));
    memset(v, false, sizeof(v));

    int i;
    for(i = 0; i < n; i++) {
        int num;
        int k;
        scanf("%d", &num);
        scanf("%d", &k);
        int j;
        for(j = 0; j < k; j++) {
            int id;
            scanf("%d", &id);
            m[num][id] = 1;
        }
    }
    bfs(1);
    for(i = 1; i <= n; i++){
        printf("%d %d\n", i, d[i]);
    }
    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] ={false};

 



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];
    }
  }
  /*
  for(int i=0;i<n;i++){
    for(int j=0;j<k[i]){


    }
    cout << endl;
  }
*/
  Queue que = Queue();

  que.push(1);

  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]);
	used[imap[p][i]] = true;
	ans[imap[p][i]] = ans[p] + 1;
      }
    }


  }


 
  for(int i=0;i<n;i++){
    cout << u[i] << " " << ans[u[i]] << endl;
  }


  return 0;
}

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


vector<int> bfs(vector<vector<int> > &graph,int start){
	queue<int> todo;
	vector<int> dist(graph.size(),-1);
	dist[start] = 0;
	todo.push(start);
	while(!todo.empty()){
		int now = todo.front();
		todo.pop();
		for (int i=0;i<graph[now].size();i++){
			int nxt = graph[now][i];
			if (dist[nxt] != -1) continue;
			dist[nxt] = dist[now] + 1;
			todo.push(nxt);
		}
	}
	return dist;
}



int main(){
	int n; cin >> n;
	vector<vector<int> > graph(n+1);
	for (int i = 0; i < n; i++){
		int v, k; cin >> v >> k;
		for (int j = 0; j < k; j++) {
			int in; cin >> in;
			graph[v].push_back(in);
		}
	}
	vector<int> dist;
	dist = bfs(graph,1);


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

	return 0;
}

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

using namespace std;

long long inf=1000000007;

int main(){
	long long n;
	cin>>n;
	vector<vector<long long>> kankei(n+1);
	vector<long long> dis(n+1,-1);

	for(long long i=0;i<n;i++){
		long long u,k;
		cin>>u>>k;
		for(long long j=0;j<k;j++){
			long long hoge;
			cin>>hoge;
			kankei.at(u).push_back(hoge);
		}
	}

	queue<long long> que;
	que.push(1);
	dis.at(1)=0;

	while(!que.empty()){
		long long now=que.front();
		que.pop();

		for(auto a:kankei.at(now)){
			if(dis.at(a)!=-1) continue;
			que.push(a);
			dis.at(a)=dis.at(now)+1;
		}
	}

	for(long long i=1;i<=n;i++){
		cout<<i<<" "<<dis.at(i)<<endl;
	}

	return 0;
}

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

int BFS(int s, int t, const vector<vector<int> >& G){
    vector<int> stock1;
    vector<int> stock2;
    stock1.push_back(s);
    int d = 0;
    while (1) {
        for (int i = 0; i < stock1.size(); i++) {
            if (stock1[i] == t) return d;
            for (int j = 0; j < G[stock1[i]].size(); j++) {
                stock2.push_back(G[stock1[i]][j]);
            }
        }
        if (stock2.empty()) return -1;
        stock1.clear();
        stock1.swap(stock2);
        d++;
    }
}

int main(){
    int n;
    cin >> n;
    vector<vector<int> > G(n + 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].push_back(v);
        }
    }
    for (int i = 1; i <= n; i++) {
        cout << i << " " << BFS(1, i, G) << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;

using Graph = vector<vector<int>>;

int main(){
int n;
cin >> n;
Graph G(n+1);
rep(i,n)
{
  int v;
  cin>>v;
  int k;
  cin >> k;
  rep(j,k)
  {int vt;
   cin >>vt;
   G[v].push_back(vt); 
  }
}

vector<int> dist(n+1,-1);
queue<int> que;

dist[1]=0;
que.push(1);

while (!que.empty())
{
  int v = que.front();
  que.pop();
  //cout << G[1].size()<<endl;
  rep(i,G[v].size())
  { int newv =G[v][i];
   if(dist[newv]==-1)
    {que.push(newv);
     dist[newv]=dist[v]+1;}
  }

}

rep(i,n)
{
  cout<< i+1 <<" "<<dist[i+1]<<endl;

}

return 0;
}
//

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

#define N 100
#define 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;
  }
}