Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve
const INFTY = (1 << 21)
const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 頂点1から頂点iまでの距離
var color, d [MAX]int

func bfs(s int) {
	var q []int
	q = append(q, s)
	for i := 0; i < n; i++ {
		d[i] = INFTY
	}
	//sは開始点なので、0をいれる
	d[s] = 0

	//キューが空になるまで、以下を繰り返す
	for len(q) > 0 {
		u := q[0]
		q = q[1:]
		for v := 0; v < n; v++ {
			if M[u][v] == 0 {
				continue
			}
			if d[v] != INFTY {
				continue
			}
			d[v] = d[u] + 1
			q = append(q, v)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Printf("%d ", i+1)
		if d[i] == INFTY {
			fmt.Printf("%d\n", -1)
		} else {
			fmt.Printf("%d\n", d[i])
		}
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	bfs(0)

}

C++: #include <stdio.h>
#include <string.h>
#include<iostream>
#include<queue>
using namespace std;

char s[13][1];
int D[106][106];
int A[106],f[106],w,h,n,sx,sy,gx,gy,e,g[106];
int   kensa(int ,int);
int main(){
	queue<int> P;
	int i,j,a,b,c,d;
	for(i=1;i<=100;i++){
		for(j=1;j<=100;j++){
			D[i][j]=-1;		
		}					
	}						
	for(i=0;i<105;i++){		
		A[i]=0;				
		f[i]=-1;
		g[i]=0;
	}							
	scanf("%d" ,&a);//     a=4
	for(i=1;i<=a;i++){
        scanf("%d",&b);		//
		scanf("%d",&b);			//b=2					//
		for(j=1;j<=b;j++){		//
		scanf("%d",&c);			//					//
		D[i][c]=1;
//
		}						//D[???][???]
	}				
	for(i=1;i<=a;i++){
		for(j=1;j<=a;j++){
	//		printf("%d %d %d\n",i,j,D[i][j]);
		}	
	}//
	P.push(1);
	//P???1
	f[1]=0;
	while(!P.empty()){			//
		d=P.front();
		//
		A[d]=1;
		//
		P.pop();				//
		for(i=1;i<=a;i++){
			//printf("%d %d %d\n",d,i,D[d][i]);//
			if(D[d][i]==-1){		//
			continue;			//
			}					//
			if(A[i]==1){		//
			continue;			//
			}					//
			P.push(i);			//
			
			g[i]=g[d]+1;
			A[i]=1;
			//printf("%d\n",P.back());
		}	
	}							//
	for(i=1;i<=a;i++){			//
	printf("%d %d\n",i, g[i]);	//
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <numeric>
#include <cassert>
#include <queue>

const int MAXINT = 1000000;

void bfs(std::vector<std::vector<int> >& adj_list, std::vector<int>& d, int root = 0 ){
  std::queue<int> target_q;
  // std::queue<int> dist_q;
  target_q.push(root);
  d[root] = 0;
  // dist_q.push(0;)
  while(!target_q.empty()){
    int vtx = target_q.front(); target_q.pop();
    for(int const&  u : adj_list[vtx]){
      target_q.push(u);
      if(d[vtx] + 1 < d[u]){
        // std::cout<< "/* message */" << std::endl;
        d[u] = d[vtx] + 1;
      }
    }
  }
}


int main(int argc, char const *argv[]) {
  int n; // .. 100
  std::cin >> n;
  std::vector<std::vector<int> > adj_list(n);
  std::vector<int> d(n, MAXINT);

  for(int q=0; q<n; ++q){
    int i_plus_1, k;
    std::cin >> i_plus_1;
    std::cin >> k;
    for(int p=0; p<k; ++p){
      int j_plus_1;
      std::cin >> j_plus_1;
      // adj[i_plus_1-1][j_plus_1-1] = true;
      adj_list[i_plus_1 - 1].push_back(j_plus_1-1);
    }
  }
  bfs(adj_list, d, 0);

  for(int i=0; i<n; ++i){

    // if(d[i] < MAXINT){
      std::cout << (i+1)
        << " " << d[i]
        << std::endl;
  }


  // for(auto it = adj_list.begin(); it != adj_list.end(); ++it){
  //   std::cout << ": ";
  //   for(auto jt = (*it).begin(); jt != (*it).end(); ++jt){
  //     std::cout << (*jt) << ' ';
  //   }
  //   std::cout << std::endl;
  // }

  return 0;
}

C++: #include<iostream>
#include<queue>

using namespace std;
 queue<int> q;

int main(){
  int n,cnt;
  int d,u,k,pnt;
  int po[101]={};

  cin>>n;
  for(int i=0;i<n;i++){
    cnt=0;
    cin>>u>>k;
    po[u]+=cnt;
    for(int j=0;j<k;j++){
      cin>>d;
      q.push(d);
    }
    cnt+=(po[u]+1);
    for(int l=0;l<k;l++){
      pnt=q.front();
      q.pop();
      if(po[pnt]==0) po[pnt]=cnt ;
    }
  }

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

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;

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<bits/stdc++.h>
using namespace std;

int G[223][223];
int dis[223];
int n;

struct st {
  int pos;
  int v;
};

int main() {
  cin >> n;
  for(int i = 1; i <= n; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    for(int j = 0; j < v; j++) {
      int t;
      scanf("%d", &t);
      G[u][t] = G[t][u] = 1;
    }
  }

  memset(dis, 0x3f, sizeof dis);

  int start = 1;
  queue<st> q;
  q.push((st) {
    1, 0
  });

  while(!q.empty()) {

    st u = q.front();
    q.pop();
    dis[u.pos] = u.v;

    for(int i = 1; i <= n; i++) {
      if(i == u.pos) continue;
      if(G[i][u.pos] == 0) continue;
      if(dis[i] <= u.v + 1) continue;
      q.push((st){i, u.v + 1});
    }
  }

  for(int i=1;i<=n;i++) {
    printf("%d %d\n", i, dis[i] > 100000 ? -1 : dis[i]);
  }

  return 0;
}

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

const int INF = 101;

vector<vector<int>> GetAdjacencyMatrix(int n)
{
	vector<vector<int>> am(n, vector<int>(n));
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		u--;
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			am[u][--v] = 1;
		}
	}
	return am;
}

void BFS(int startNode, int n, const vector<vector<int>>& am, vector<int>& minDistances)
{
	queue<int> q;
	q.push(startNode);
	while (!q.empty()) {
		int node = q.front();
		q.pop();
		for (int i = 0; i < n; i++) {
			if (am[node][i] == 0) continue;
			if (minDistances[i] != INF) continue;
			q.push(i);
			int distance = minDistances[node] + 1;
			minDistances[i] = min(minDistances[i], distance);
		}
	}
}

int main()
{
	int n;
	cin >> n;
	vector<vector<int>> am = GetAdjacencyMatrix(n);
	vector<int> minDistances(n, INF);
	minDistances[0] = 0;
	BFS(0, n, am, minDistances);
	for (int i = 0; i < n; i++) {
		if (minDistances[i]==INF) cout << i + 1 << " " << -1 << endl;
		else cout << i + 1 << " " << minDistances[i] << endl;
	}
}