Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	visitedAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		visitedAt: -1,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.visitedAt >= 0
}

func bfs(id vertexId, vqueue []vertexId, vertices []vertex) {
	vertex := &vertices[id-1]
	for _, vid := range vertex.adjs {
		if !vertices[vid-1].isVisited() {
			(&vertices[vid-1]).visitedAt = vertex.visitedAt+1
			vqueue = append(vqueue, vid)
		}
	}
	if len(vqueue) > 0 {
		nextId := vqueue[0]
		nextVqueue := vqueue[1:]
		bfs(nextId, nextVqueue, vertices)
	}
}

func solveBfs(vertices []vertex) {
	vertex := &vertices[0]
	vertex.visitedAt = 0
	vqueue := make([]vertexId, 0)
	bfs(vertex.id, vqueue, vertices)
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveBfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d\n", vertices[i].id, vertices[i].visitedAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

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

using namespace std;
int ans[100][100] = {};
int now = 0, n;

int main() {
    int u, k, tmp;
    cin >> n;
    vector<int> dist(n, -1);
    queue<int> que;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            cin >> tmp;
            ans[u - 1][tmp - 1] = 1;
        }
    }
/*
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; ++j) {
            cout << ans[i][j] << " ";
        }
        cout << endl;
    }
*/
    dist[0] = 0;
    que.push(0);
    while (!que.empty()) {
        int v = que.front();
        //cout << v;
        que.pop();

        for (int i = 0; i < n; ++i) {
            int nv = ans[v][i];
            if (dist[i] == -1 and nv != 0) {
                dist[i] = dist[v] + 1;
                que.push(i);
            }
        }
        //cout << endl;
    }
    for (int i = 0; i < n; ++i) {
        cout << i + 1 << " " << dist[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];  // 距離で訪問状態（color）を管理する

void bfs(int s) {
  queue<int> q;  // 標準ライブラリの queue を使用
  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<bits/stdc++.h>
using namespace std;
int vis[111],G[111][111],cn,n,d[111];
int  bfs(int i){
  	queue<int>q;
  	q.push(i);
  	vis[i]=1;
	while(!q.empty()){
		int temp=q.front();
		vis[temp]=1;
		q.pop();
		for(int j=1;j<=n;j++){
			if(vis[j]==0&&G[temp][j]!=0){
				d[j]=d[temp]+1;
				vis[j]=1;
				q.push(j);
			}
		}
	}  
}

int main(){
    scanf("%d",&n);
	for(int i=1;i<=n;i++){	
	int v2,v1,k;
		scanf("%d%d",&v1,&k);
		for(int j=0;j<k;j++){
			scanf("%d",&v2);
			G[v1][v2]=1;
		}
}
    bfs(1);
    for(int i=1;i<=n;i++) {
    	if(i==1)
    	printf("%d %d\n",i,d[i]);
    	else if(d[i]==0){
    			printf("%d %d\n",i,-1);
		} 
		else printf("%d %d\n",i,d[i]);
	}
	 
	 return 0;
}

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

#define REP(i,n) for(int i=0;i<n;i++)

using namespace std;


int main()
{
	int n;
	cin>>n;
	
	bool adj[n+10][n+10]={};
	
	for(int i=1;i<n+1;++i){//1index
		
		int u;
		int k;
		cin>>u>>k;
		
		for(int j=1;j<k+1;++j){//1index
			int v;
			cin>>v;
			adj[i][v]=true;
		}
	}
	
	int d[n+10];
	for(int i=1;i<n+1;++i){
		d[i]=-1;
	}
	
	d[1]=0;
	
	queue<int> que;
	que.push(1);
	while(!que.empty()){
		int now=que.front();
		que.pop();
		
		int a=d[now];
		
		for(int j=1;j<n+1;++j){
			
			if((adj[now][j]) and (d[j]==-1)){
				d[j]=a+1;
			que.push(j);
			
			}
			
		}
	}
	
	for(int i=1;i<n+1;++i){
		cout<<i<<" "<<d[i]<<endl;
	}
	
}

C++: #include <iostream>
#include <queue>
using namespace std;
    queue<int> Q;
int u[1000][1000];
int d[1000],color[1000];
// white 0 gray 1 black 2
void BFS(int s,int n){
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            color[i]=0;
            d[i]=-1;
        }
    }
    color[s]=1;
    d[s]=0;
    Q.push(s);
    while(Q.size()!=0){
        int tmp=Q.front();
        Q.pop();
        for(int j=1;j<=n;j++){
            if(color[j]==0 && u[tmp][j]==1){
                color[j]=1;
                d[j]=d[tmp]+1;
                Q.push(j);
            }
        }
        color[tmp]=2;
    }
}
int main(){
    int n,l,k,m;
    cin>>n;
    u[100][100]={};
    for(int i=0;i<n;i++){
        cin>>l>>k;
        for(int j=1;j<=k;j++){
            cin>>m;        
            u[l][m]=1;
        }
    }
    BFS(1,n);
    for(int i=1;i<=n;i++){
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}

C++: // Ki
// 所要時間 25分 (1WA)
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define REP(i, d, n) for(int i=(d); i<(n); ++i)
#define all(v) v.begin(), v.end()

int main() {

    int n;
    cin >> n;
    vector<vector<int> > graph(n);
    rep(i, n){
        int u, k;
        cin >> u >> k;
        --u;
        rep(j, k){
            int v;
            cin >> v;
            graph[u].push_back(--v);
        }
    }

    queue<int> q;
    vector<int> dis(n, -1);
    q.push(0);
    dis[0] = 0;
    while(!q.empty()){
        int v = q.front();
        q.pop();
        rep(i, graph[v].size()){
            int u = graph[v][i];
            if(dis[u] == -1){
                dis[u] = dis[v] + 1;
                q.push(u);
            }
        }
    }

    rep(i, n){
        cout << i+1 << " " << dis[i] << endl;
    }

    return 0;
}