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 <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <list>
#include <utility>
#include <ctime>
#define INF 1000000000
#define LINF 9000000000000000000
#define mod 1000000007
 
#define rep(i,n) for(int i=0;i<int(n);i++)
#define rrep(i,n) for(int i=(n);i>=0;i--)
#define REP(i,a,b) for(int i=(a);i<int(b);i++)
#define all(x) (x).begin(),x.end()
#define vector_rsort(x) sort(all(x));reverse(all(x))
#define array_rsort(x,n) sort(x,x+n);reverse(x,x+n);
#define pb push_back
#define mp make_pair
#define MOD(x) (x%(mod))

#define Yes cout<<"Yes"<<endl
#define YES cout<<"YES"<<endl
#define No cout<<"No"<<endl
#define NO cout<<"NO"<<endl
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef pair<int,int> pi;
 
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
bool debug=false;
/*---------------------------------------------------*/

int n,u,k,v;
int g[105][105];

void init(){
  rep(i,105){
    rep(j,105){
      g[i][j]=INF;
    }
  }
}

void wf(){
  rep(k,105){
    rep(i,105){
      rep(j,105){
	g[i][j]=min(g[i][j],g[i][k]+g[k][j]);
      }
    }
  }
}

int main(){
  init();
  cin>>n;
  rep(i,n){
    cin>>u>>k;
    rep(i,k){
      cin>>v;
      g[u][v]=1;
    }
  }
  wf();
  for(int i=1;i<=n;i++){
    if(g[1][i]==INF)cout<<i<<" "<<0<<endl;
    else cout<<i<<" "<<g[1][i]<<endl;
  }
  return 0;
}

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

int main(void){
  int N;
  cin >> N;
  
  vector<vector<int>> G(N);
  for(int i=0;i<N;i++){
    int u,k;
    cin >> u >> k;
    for(int j=0;j<k;j++){
      int tmp;
      cin >> tmp;
      G[i].push_back(tmp-1);
    }
  }
  
  vector<int> S(N);
  for(int i=0;i<N;i++){
    S[i] = -1;
  }
  queue<pair<int,int>> Q;
  for(auto it:G[0]){
    Q.push(make_pair(it,1));
  }
  S[0] = 0;
  while(!Q.empty()) {
    auto i = Q.front();
    Q.pop();
    if(S[i.first]>-1){
      continue;
    } else {
      S[i.first] = i.second;
    }
      
    for(auto it: G[i.first]){
      Q.push(make_pair(it,i.second+1));
    }
  }
  
  for(int i=0;i<N;i++){
    cout << i+1 << " " << S[i] << endl;
  }
}

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(){
  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++: #include <iostream>
#include <queue>
using namespace std;

int n;
bool A[105][105];
int D[105];

void bfs(int src){
    queue<int> Q;
    Q.push(src);
    D[src] = 0;
    while(!Q.empty()){
        int cur = Q.front();
        Q.pop();
        for(int dst=0; dst<105; dst++){
            if(A[cur][dst]==1 && D[dst]==-1){
                D[dst]=D[cur]+1;
                Q.push(dst);
            }
        }
        
    }
}

int main(int argc, const char * argv[]) {
    for(int i=0; i<105; i++){
        for(int j=0; j<105; j++){
            A[i][j] = 0;
        }
    }
    cin >> n;
    for(int i=0; i<n; i++){
        int u;
        int k;
        cin >> u >> k;
        u--;
        for(int j=0; j<k; j++){
            int v;
            cin >> v;
            v--;
            A[u][v] = 1;
        }
    }
    for(int i=0; i<105; i++){
        D[i] = -1;
    }
    bfs(0);
    for(int i=0; i<n; i++){
        cout << i+1 << " " << D[i] << endl;
    }
    return 0;
}

C++: #if 0
IDが1から始まることをどのように扱うかを最初にしっかり定義していなかったせいで時間がかかってしまった。
#endif

#include <iostream>
#include <vector>
#include <queue>
#include <map>
using namespace std;

map<int, vector<int>> init(int N)
{
    map<int, vector<int>> P;
    for (int i = 0; i < N; i++)
    {
        int id, dataNum;
        cin >> id >> dataNum;
        vector<int> temp;
        for (int j = 0; j < dataNum; j++)
        {
            int tempNode;
            cin >> tempNode;
            temp.push_back(tempNode);
        }
        P[id - 1] = temp; // P[i] = 隣接ノード
    }
    return P;
}

int main()
{
    int N;
    cin >> N;
    map<int, vector<int>> P = init(N);
    int distance[N];
    for (int i = 0; i < N; i++)
    {
        distance[i] = -1;
    }
    distance[0] = 0;
    queue<int> Q = queue<int>({0});
    while (!Q.empty())
    {
        int cur = Q.front(); // 現在地
        Q.pop();
        for (int itr = 0; itr < P[cur].size(); itr++)
        {
            int dst = P[cur][itr] - 1;
            if (distance[dst] == -1)
            {
                distance[dst] = distance[cur] + 1;
                Q.push(dst);
            }
        }
    }
    for (int i = 0; i < N; i++)
    {
        cout << i + 1 << " " << distance[i] << endl;
    }
}