Go: package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)

	g := make([][]int, n+1)
	d := make([]int, n+1)
	for i := 0; i < n; i++ {
		var u,k int
		fmt.Scan(&u)
		fmt.Scan(&k)
		g[u] = make([]int, k)
		for j := 0; j < k; j++ {
			fmt.Scan(&g[u][j])
		}

		d[i+1] = -1
	}

	q := [][]int{}
	q = append(q, []int{1, 0})
	for len(q) > 0 {
		pop := q[0]
		if len(q) > 1 {
			q = q[1:]
		} else {
			q = [][]int{}
		}
		if d[pop[0]] >= 0 {
			continue
		}
		d[pop[0]] = pop[1]

		for j := 0; j < len(g[pop[0]]); j++ {
			q = append(q, []int{g[pop[0]][j], pop[1]+1})
		}
	}

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

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

const int nIMPOS = -1;
struct StDir
{
  int m_nx;
  int m_nEtc;

  StDir(int nx) : m_nx(nx), m_nEtc(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<int>& rvnDst)
{
  int nxSiz;
  cin >> nxSiz;

  rvvnAdjcy.resize(nxSiz + 1, vector<int>(nxSiz + 1, 0));
  for (int i = 0; i < nxSiz; ++i)
  {
    int nx, nySiz;
    cin >> nx >> nySiz;
    for (int j = 0; j < nySiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  rvnDst.resize(nxSiz + 1, nIMPOS);
}

void fnBreadthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, 
                          queue<StDir>& rqoBFSrch, vector<int>& rvnDst)
{
  while (rqoBFSrch.size())
  {
    StDir oDir = rqoBFSrch.front(); rqoBFSrch.pop();
    if (rvnDst[oDir.m_nx] == nIMPOS)  continue;

    for (int ny = 1; ny < cnrvvnAdjcy[oDir.m_nx].size(); ++ny)
      if (cnrvvnAdjcy[oDir.m_nx][ny] == 1)
      {
        int nDst = rvnDst[oDir.m_nx] + 1;
        if (rvnDst[ny] == nIMPOS)
          rvnDst[ny] = nDst;
        else
          rvnDst[ny] = min(rvnDst[ny], nDst);

        StDir oDir(ny);
        rqoBFSrch.push(oDir);
      }
  }
}

void fnResult(const vector<int>& cnrvnDst)
{
  for (int i = 1; i < cnrvnDst.size(); ++i)
    cout << i <<  " " << cnrvnDst[i] << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  queue<StDir> qoBFSrch;
  vector<int>  vnDst;

  fnInput(vvnAdjcy, vnDst);

  vnDst[1] = 0;
  StDir oDir(1);
  qoBFSrch.push(oDir);
  fnBreadthFirstSearch(vvnAdjcy, qoBFSrch, vnDst);
  fnResult(vnDst);

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <climits>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define repR(i, n) for(int i = (n) - 1; i > -1; i--)
#define rep1(i, n) for(int i = 1; i < (int)(n + 1); i++)
#define rep1R(i, n) for(int i = (n); i > 0; i--)
using namespace std;

static const int INFTY = INT_MAX;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
int M[110][110] = {};
int color[110];
int d[110];
queue<int> Q;

void bfs(int s) {
  rep(u, n) color[u] = WHITE;
  rep(u, n) d[u] = INFTY;

  color[s] = GRAY;
  d[s] = 0;
  Q.push(s);

  while (!Q.empty()) {
    int u = Q.front(); Q.pop();
    rep(v, n) {
      if (M[u][v] && color[v] == WHITE) {
        color[v] = GRAY;
        d[v] = d[u] + 1;
        Q.push(v);
      }
    }
    color[u] = BLACK;
  }
}

int main() {
  cin >> n;
  rep(i, n) {
    int id, deg;
    cin >> id >> deg;
    --id;    // 0-indexedに直す
    rep(j, deg) {
      int v;
      cin >> v;
      --v;    // 0-indexedに直す
      ++M[id][v];
    }
  }
  bfs(0);
  rep(i, n) {
    cout << i + 1 << " ";
    if (d[i] != INFTY) cout << d[i];
    else cout << -1;
    cout << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <queue>
using namespace std;
static const int N = 100;
void bfs(int);
int n,M[N][N],d[N],u,i,j;
string color[N];
int main(){
  int inu,k,v;
  cin >> n;
  for(i=1;i<=n;i++){
    for(j=1;j<=n;j++){
      M[i][j]=0;
    }
  }
  for(i=1;i<=n;i++){
    cin >> inu >> k;
    for(j=0;j<k;j++){
      cin >> v;
      M[inu][v]=1;
    }
  }
  bfs(1);
  for(i=1;i<=n;i++){
    if(d[i]>1000000) cout << i << ' ' << -1 << endl;
    else cout << i << ' ' << d[i] << endl;
  }
  return 0;
}
void bfs(int s){
  queue<int> q;
  for(i=1;i<=n;i++){
    color[i]="WHITE";
    d[i]=1000000000;
  }
  color[s]="GLAY";
  d[s]=0;
  q.push(s);
  while(q.empty()!=true){
    u=q.front();
    q.pop();
    for(i=1;i<=n;i++){
      if(M[u][i]&&color[i]=="WHITE"){
	color[i]="GLAY";
	d[i]=d[u]+1;
	q.push(i);
      }
    }
    color[u]="BLACK";
  }
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

class Graph{
public:
  int v;
  int cost = inf;
  int ftime = -1;
  int ltime = -1;
  vector<int> e;
};
vector<Graph> g;
int cnt = 0;
void dfs(int pos){
  if( g[pos].ftime != -1 ) return;
  cnt++;
  g[pos].ftime = cnt;
  for(int i=0; i<g[pos].e.size(); i++){
    dfs(g[pos].e[i]);
  }
  cnt++;
  g[pos].ltime = cnt;
}
void bfs(int pos){
  for(int i=0; i<g[pos].e.size(); i++){
    // if( g[ g[pos].e[i] ].cost != inf ) continue;
    g[ g[pos].e[i] ].cost = min(g[ g[pos].e[i] ].cost, g[pos].cost + 1);
    bfs(g[pos].e[i]);
  }
}

int main(void) {

  int n;
  cin >> n;
  g.resize(n);
  int u, k;
  for(int i=0; i<n; i++){
    cin >> u >> k;
    u--;
    g[u].v = u;
    g[u].e.resize(k);
    for(int j=0; j<k; j++){
      cin >> g[u].e[j];
      g[u].e[j]--;
    }
    sort(g[u].e.begin(), g[u].e.end());
  }

  g[0].cost = 0;
  bfs(0);
  for(int i=0; i<n; i++) cout << g[i].v + 1 << " " << (g[i].cost == inf ? -1 : g[i].cost) << endl;

  // for(int i=0; i<n; i++) dfs(i);
  // for(int i=0; i<n; i++){
  //   cout << g[i].v + 1 << " " << g[i].ftime << " " << g[i].ltime << endl;
  // }



  return 0;
}

// EOF

C++: #include <iostream>
#include <stdio.h>
#include <queue>
 
using namespace std;
#define N 100
#define INF 2000000
 
int n, M[N][N];
int d[N];
 
void bfs(int s){
    int i,u,v;
 
    queue<int> q;
    q.push(s);
    for(i = 0; i < n; i++){
        d[i] = INF;
    }
 
    d[s] = 0;
 
    while(!q.empty()){
        u = q.front();
        q.pop();
        for(v = 0; v < n; v++){
            if(M[u][v] == 0) continue;
            if(d[v] != INF) continue;
            d[v] = d[u] + 1;
            q.push(v);
        }
    }
    for(i = 0; i < n; i++){
        if(d[i] == INF){
            printf("%d -1\n", i+1);
        }else{
            printf("%d %d\n", i+1, d[i]);
        }
    }
}
 
 
int main(void){
    int i,j,u,k,v;
 
    scanf("%d", &n);
 
    for(i = 0;i < n; i++){
        for(j = 0; j < n; j++){
            M[i][j] = 0;
        }
    }
 
    for(i = 0; i < n; i++){
      cin >> u >> k;
        u--;
        for(j=0;j<k;j++){
          cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
 
    bfs(0);
 
    return 0;
}

C++: #include<iostream>
#include<stdio.h>

using namespace std;
int d[101];

int n;
int M[101][101];
int Q[101];
int head = 0;
int tail = 0;

void enqueue(int x) {
	Q[tail] = x;
	if (tail == (tail - head)) {
		tail = 1;
	}
	else {
		tail = tail + 1;
	}
}

void BFS(int s) {
	enqueue(s);
	d[s] = head;
	while (head != tail) {
		s = Q[head];
		head = head + 1;
		
		for (int j = 1; j < n + 1; j++) {
			if (M[s][j] == 1) {
				if(d[j] == -1){
					d[j] = d[s] + 1;
					enqueue(j);
				}

			}
		}

	}
}

int main() {
	int  u, k, v;//頂点数、頂点の番号、出次数、隣接する頂点の番号
	

	cin >> n;



	//初期化
	for (int i = 0; i < 101; i++) {
		d[i] = -1;
		
		for (int j = 0; j < 101; j++) {
			M[i][j] = 0;

		}
	}


	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			M[u][v] = 1;
		}
	}


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

	return 0;
}