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>
using namespace std;
template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v){
  const char* dlm = "";
  for(const auto& x:v) cout << exchange(dlm, "\t") << x;
  return os;
}
struct Graph{
  // size_t time;
  vector<vector<size_t>> v;
  // vector<size_t> d,f;
  vector<int32_t> d;
  // Graph(size_t n): time(1), v(n), d(n,0), f(n) {}
  Graph(size_t n): v(n), d(n,-1) {}
  // void dfs(size_t i){
  //   d[i]=time++;
  //   for(const auto& x:v[i]) if(d[x-1]==0) dfs(x-1);
  //   f[i]=time++;
  // }
  void bfs(size_t n){
    d[n]=0;
    deque<size_t> que(1,n);
    while(!que.empty()){
      size_t x=que.front(); que.pop_front();
      for(const auto& y:v[x]){
        if(d[y-1]==-1){
          d[y-1]=d[x]+1;
          que.push_back(y-1);
        }
      }
    }
  }
};
ostream& operator<<(ostream& os, const Graph& x){
  for(size_t i=0; i<x.v.size(); ++i)
    // cout<<(i+1)<<' '<<x.d[i]<<' '<<x.f[i]<<'\n';
    cout<<(i+1)<<' '<<x.d[i]<<'\n';
  return os;
}
int32_t main(){
  size_t n; cin>>n;
  Graph graph(n);
  for(size_t i=0; i<n; ++i){
    size_t id,k; cin>>id>>k;
    graph.v[id-1].resize(k); for(auto&& x:graph.v[id-1]) cin>>x;
  }
  graph.bfs(0);
  cout<<graph;
}

C++: #include <iostream>
#include <cstdlib>
#include <string>
#include <typeinfo>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
static const int INFTY = (1<<21);
int n,M[N][N], 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);
    return 0;
}

C++: //
//
//  algoC.cpp - created by us162022
//
#include <iostream>
#include <queue>
using namespace std;
struct Node{
  int u,k,v[99];
  int distance;
};

int main(int argc, char *argv[])
{
  int n;
  Node node[100];
  queue<Node> que;

  cin >> n;

  for(int i=0; i<n; i++){
    cin >> node[i].u >> node[i].k;

    for(int j=0; j<node[i].k; j++)
      cin >> node[i].v[j];

    node[i].distance=-1;
  }

  node[0].distance = 0;
  que.push(node[0]);

  while(!que.empty()){
    Node fro = que.front();

    for(int i=0; i<fro.k; i++){
      int x = fro.v[i]-1;
  
      if(node[x].distance==-1)
	    node[x].distance = fro.distance+1;

      que.push(node[x]);
    }

    que.pop();
  }

  for(int i=0; i<n; i++)
    cout << node[i].u << " " << node[i].distance << endl;

}

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

#define REP(i, n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()
const int INF = 1e9;

using namespace std;
int adj[105][105] = {0};
int res[105] = {0};
int n;

int main() {
    cin >> n;
    REP(i, n){
        int u, k;
        cin >> u >> k;
        REP(j, k) {
            int tmp;
            cin >> tmp;
            adj[u-1][tmp-1] = 1;
        }
        res[i] = INF;
    }
    res[0] = 0;
    REP(i, n) REP(j, n)
        if(adj[i][j] != 0)
            res[j] = min(res[j], res[i]+1);

    REP(i, n){
        if(res[i] != INF)
            cout << i+1 << " " << res[i] << endl;
        else
            cout << i+1 << " -1" << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <stack>
#include <vector>
#include <algorithm>
#include <cmath>
#include <climits>
#include <cstring>
#include <queue>
#include <string>

using namespace std;

const double PI = 3.14159265358979;

int G[101][101];
bool visited[101];
int timex[101][2];
int deep[101];
int now_time = 1;
int n;

void dfs(int node) {

	if (!visited[node]) {
		visited[node] = 1;
		timex[node][0] = now_time++;
		for (int i = 0; i < n; i++)	{
			if (G[node][i] && visited[i] == 0) {
				dfs(i);
			}
		}
		timex[node][1] = now_time++;
	}
}

void dfs_stack(int node) {

	stack<int> st;
	st.push(node);
	visited[node] = 1;
	timex[node][0] = now_time++;
	while (!st.empty()) {
		int ver = st.top();

		bool flag = false;
		for (int i = 0; i < n; i++)	{
			if (G[ver][i] && visited[i] == 0) {
				visited[i] = 1;
				timex[i][0] = now_time++;
				st.push(i);
				flag = true;
				break;
			}
		}
		if (!flag) {
			timex[ver][1] = now_time++;
			st.pop();
		}
	}
}

void bfs(int node, bool reach) {

	queue<int> Q;
	visited[node] = 1;
	if (!reach) deep[node] = -1;
	Q.push(node);

	while (!Q.empty()) {

		int top = Q.front();
		Q.pop();
		for (int i = 0; i < n; i++)	{
			if (G[top][i] && !visited[i]) {
				Q.push(i);
				visited[i] = 1;
				if (reach)
					deep[i] = deep[top] + 1;
				else
					deep[i] = -1;
			}
		}
	}
}


int main() {
	
	cin >> n;

	for (int i = 0; i < n; i++)	{
		int id, degree;
		cin >> id >> degree;
		for (int j = 0; j < degree; j++) {
			int idx; cin >> idx;
			G[id - 1][idx - 1] = 1;
		}
	}

	bool first = true;
	for (int i = 0; i < n; i++) {
		if (!visited[i]) {
			bfs(i, first);
			first = false;
		}
	}
	

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


	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)
{
  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()
{
  //入力
  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);

}