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 <stdio.h>
#include <iostream>
#include <utility>
#include <algorithm>
#include <math.h>
#include <vector>
#include <list>
#define inf 200
using namespace std;

int n;
list<int> adj[101];
int d[101];
bool f[101];
void BFS(int v)
{
    int m = 0;
    f[v] = false;
    while (!adj[v].empty())
    {
        d[adj[v].front()] = min(d[v] + 1, d[adj[v].front()]);
        adj[v].pop_front();
    }
    for (int i = 1; i <= n; i++)
    {
        if (f[i] && d[i] < d[m])
            m = i;
    }
    if (m > 0)
        BFS(m);
}

void print()
{
    for (int i = 1; i <= n; i++)
    {
        if (d[i] == inf)
            d[i] = -1;
        printf("%d %d\n", i, d[i]);
    }
}

int main()
{
    int u, k, v;
    cin >> n;

    for (int i = 0; i < n; i++)
    {
        cin >> u >> k;
        while (k > 0)
        {
            cin >> v;
            adj[u].push_back(v);
            k--;
        }
    }
    for (int i = 0; i <= n; i++)
    {
        d[i] = inf;
        f[i] = true;
    }
    d[1] = 0;
    BFS(1);

    print();

    return 0;
}

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

class Adjl{
private:
	int u;
	int k;
	Adjl **next;
public:
	Adjl(int u);
	~Adjl(){ if (next != NULL) delete[] next; }
	void setV(int k, Adjl *vk);
	int breadthFirstSearch(int id);
	void print(int id);
};

Adjl::Adjl(int u)
{
	this->u = u;
	k = 0;
	next = NULL;
}

void Adjl::setV(int k, Adjl *vk)
{
	if (this->k == 0) next = new Adjl*[k];
	next[this->k] = vk;
	(this->k)++;
}

int Adjl::breadthFirstSearch(int id)
{
	if (id == u) return 0;
	int d_min = -1;
	for (int i = 0; i < k; i++) {
		if (d_min == -1) d_min = next[i]->breadthFirstSearch(id) + 1;
		else d_min = min(next[i]->breadthFirstSearch(id) + 1, d_min);
	}
	return d_min;
}

void Adjl::print(int id)
{
	cout << id << " " << breadthFirstSearch(id) << endl;
}

int main(void)
{
	int n;
	cin >> n;
	
	Adjl **adjl = new Adjl*[n];
	int check[100] = {0};

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		if (check[i] == 0) {
			adjl[i] = new Adjl(u);
			check[i] = 1;
		}
		check[i] = 1;
		for (int j = 0; j < k; j++) {
			int vk;
			cin >> vk;
			if (check[vk - 1] == 0) {
				adjl[vk - 1] = new Adjl(vk);
				check[vk - 1] = 1;
			}
			adjl[i]->setV(k, adjl[vk - 1]);
		}
	}

	for (int i = 1; i <= n; i++) {
		adjl[0]->print(i);
	}

	delete[] adjl;
	return 0;
}

C++: #include <bits/stdc++.h>
#define REP(i,n) for (int i = 0; i <(n); ++i)
#define REP2(i,x,n) for (int i = x; i <(n); ++i)
#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
using namespace std;
using ll = long long;
using P = pair<int,int>;
static const double PI = acos(-1);

static const int N = 100;
static const int INF = (1<<21);

int d[N]; //距離で訪問状態を管理する
int n, M[N][N];

void bfs(int s){
  queue<int> q;
  q.push(s);

  REP(i,n) d[i] = INF;

  d[s] = 0;
  int u;
  while(!q.empty()){
    u = q.front(); q.pop();
    REP(v,n){
      //つながっていなかったら，飛ばす
      if(M[u][v] == 0) continue;
      //既に訪れていたら，飛ばす
      if(d[v] != INF) continue;

      d[v] = d[u] + 1;
      q.push(v);
    }
  }

  REP(i,n){
    cout << i + 1 << " " << ((d[i] == INF) ? (-1) : d[i] ) << endl;
  }




}
int main(){
  int u, k, v;
  cin >> n;
  REP(i,n){
    REP(j,n) M[i][j] = 0;
  }

  REP(i,n){
    cin >> u >> k;
    --u;
    REP(i,k){
      cin >> v;
      --v;
      M[u][v] = 1;
    }
  }

  bfs(0);
  return 0;
}

C++: 
//push(),pop():C++ではstackと統一されいる
//front():先頭の要素が何かを返す
//back():末尾の要素が何であるかを返す
//empty():キューが空であるかどうかを調べる
//size():要素数を調べる
#include<stdio.h>
#include <iostream>
#include <queue>
using namespace std;
#define MAX 101
#define WHITE 0
#define GRAY 1
#define BLACK 2
static const int INFTY = (1<<21);

int G[MAX][MAX],color[MAX],d[MAX],num;

void bfs(int s){
  int u;
  queue<int> Q; //Qを使うことでエンキュー、デキューの操作が容易になる
  for(int i=1; i<=num; i++) {
    d[i] = INFTY;
  }
  Q.push(s);
  d[s] = 0;
  while(!Q.empty()){
    u = Q.front();
    Q.pop();
    for(int v=1; v<=num; v++){
      if(G[u][v] == 0) continue;
      if(d[v] != INFTY) continue;
      d[v] = d[u] + 1;
      Q.push(v);
    }
  }
}


int main(){
  int i,j,u,k,v;

  scanf("%d",&num);
  for(i=1; i<=num; i++){
    color[i] = WHITE;
    for(j=1; j<=num; j++){
      G[i][j] = 0;
    }
  }
  for(i=1; i<=num; i++){
    scanf("%d%d",&u,&k);
    for(j=1; j<=k; j++){
      scanf("%d",&v);
      G[u][v] = 1;
    }
  }

  bfs(1);

  for(i=1; i<=num; i++) {
    if(d[i] == INFTY) printf("%d -1\n",i);
    else printf("%d %d\n",i,d[i]);
  }

  return 0;
}

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

#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n;
bool G[MAX + 1][MAX + 1];
int col[MAX + 1];
int d[MAX + 1];

void init(int n) {
	for (int i = 1; i <= n; i++) {
		col[i] = WHITE;
		d[i] = -1;
		for (int j = 1; j <= n; j++)
			G[i][j] = 0;
	}
}

void bfs(int u) {
	queue<int> Q;
	Q.push(u);
	col[u] = GRAY;
	d[u] = 0;
	while (!Q.empty()) {
		int v = Q.front();
		Q.pop();
		for (int i = 1; i <= n; i++) {
			if (G[v][i] && col[i] == WHITE) {
				Q.push(i);
				col[i] = GRAY;
				d[i] = d[v] + 1;
			}
		}
		col[v] = BLACK;
	}
}

int main() {
	cin >> n;
	init(n);
	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][v] = 1;
		}
	}
	bfs(1);
	for (int u = 1; u <= n; u++) {
		cout << u << " " << d[u] << endl;
	}
	return 0;
}

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


int main(){
  int n;
  cin >> n;
  vector<vector<int>> g(n);
  for(int i=0;i<n;++i){
    int id,k;
    cin >> id >> k;
    id--;
    for(int j=0;j<k;++j){
      int v;
      cin >> v;
      v--;
      g[id].push_back(v);
    }
  }
  vector<int> dist(n,-1);
  queue<int> que;
  dist[0]=0;
  que.push(0);
  while(!que.empty()){
    int v=que.front();
    que.pop();
    for(auto nv : g[v]){
      if(dist[nv]!=-1)continue;
      dist[nv]=dist[v]+1;
      que.push(nv);
    }
  }
  for(int i=0;i<n;++i){
    cout << i+1 << " " << dist[i] << endl;
  }
  return 0;
}