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 <stdio.h>
#include <string.h>
#include<iostream>
#include<queue>
using namespace std;

char s[13][1];
int D[102][102];
int A[100],f[100],w,h,n,sx,sy,gx,gy,e,g[100];
int   kensa(int ,int);
int main(){
	queue<int> P;
	int i,j,a,b,c,d;
	for(i=0;i<100;i++){
		for(j=0;j<100;j++){
			D[i][j]=-1;		
		}					
	}						
	for(i=0;i<100;i++){		
		A[i]=0;				
		f[i]=0;
		g[i]=0;
	}							
	scanf("%d" ,&a);//     a=4
	for(i=1;i<=a;i++){
        scanf("%d",&b);		//
		scanf("%d",&b);			//b=2					//
		for(j=1;j<=b;j++){		//
		scanf("%d",&c);			//					//
		D[i][c]=1;
//
		}						//D[???][???]
	}				
	for(i=1;i<=a;i++){
		for(j=1;j<=a;j++){
		//	printf("%d %d %d\n",i,j,D[i][j]);
		}	
	}//
	P.push(1);
	//P???1
	while(!P.empty()){			//
		d=P.front();
		//
		A[d]=1;
		//
		P.pop();				//
		for(i=1;i<=a;i++){
			//printf("%d %d %d\n",d,i,D[d][i]);//
			if(D[d][i]==-1){		//
			continue;			//
			}					//
			if(A[i]==1){		//
			continue;			//
			}					//
			P.push(i);			//
			f[i]=g[d]+1;
			g[i]=g[d]+1;
			A[i]=1;
			//printf("%d\n",P.back());
		}	
	}							//
	for(i=1;i<=a;i++){			//
	printf("%d %d\n",i, f[i]);	//
	}
	return 0;
}

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

enum Status {WHITE, GRAY, BLACK};

queue<int> que;
Status *status;
int *dist;
vector<vector<int> > a;
int n;

int main(){
        cin>>n;
        a = vector<vector<int> >(n, vector<int>());
        status = new Status[n];
        dist = new int[n];

        int m, k, r;
        for(int i=0;i<n;i++){
                cin>>r;
                cin>>m;
                for(int j=0;j<m;j++){
                        cin>>k;
                        a[r-1].emplace_back(k-1);
                }
        }
        for(int i=0;i<n;i++) status[i] = WHITE;
        for(int i=0;i<n;i++) dist[i] = -1;

        que.push(0);
        dist[0] = 0;
        while(!que.empty()){
                int v = que.front(); que.pop();
                if(status[v]==BLACK) continue;
                for(int i=0;i<a[v].size();i++){
                        if(status[a[v][i]]==WHITE){
                                dist[a[v][i]] = dist[v]+1;
                                status[a[v][i]] = GRAY;
                                que.push(a[v][i]);
                        }
                }
                status[v] = BLACK;
        }

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

C++: //#define LOCAL

#include<bits/stdc++.h>

using namespace std;

#define rep(a, b) for(int i = a; i <= b; i++)
#define mst(a) memset(a, 0, sizeof(a))

const int MAX = 1e2 + 10;


bool mtx[MAX][MAX];
int vis[MAX];
int n;

queue<int> q;

void init(void)
{
	while(!q.empty())
		q.pop();
	mst(vis);
	mst(mtx);
	n = 0;
	return;
}

bool check(int x, int y)
{
	if(mtx[x][y] && !vis[y])
		return true;
	return false;
}

void GetAns(void)
{
	rep(2, n)
	{
		if(vis[i] == 0)
			vis[i] = -1;
	}
	return;
}

void Bfs(void)
{
	q.push(1);
	while(!q.empty())
	{
		int cur = q.front();
		q.pop();
		rep(1, MAX - 10)
		{
			if(check(cur, i))
			{
				q.push(i);
				vis[i] = vis[cur] + 1;
			}
		}
	}
	return;
}

int main()
{
/*#ifdef LOCAL
	freopen("in.txt", "r", stdin);
#endif*/

	while(~scanf("%d", &n))
	{
		rep(1, n)
		{
			int row;
			scanf("%d", &row);
			int num;
			scanf("%d", &num);
			for(int j = 1; j <= num; j++)
			{
				int tmp;
				scanf("%d", &tmp);
				mtx[row][tmp] = true;
			}
		}
		
		Bfs();

		GetAns();
		
		rep(1, n)
			printf("%d %d\n", i, vis[i]);
	}
	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);
    int i, u, v;
    for ( i = 0; i < n; i++ ) d[i] = INFTY;
    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] != INFTY ) continue;
            d[v] = d[u] + 1;
            q.push(v);
            }
        }
 
        for ( i = 0; i < n; i++ ) {
            cout << i+1 << " " << ( (d[i] == INFTY) ? (-1) : d[i] ) << endl;
    }
}
 
int main() {
    int u, k, v, i, j;
 
    cin >> 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 <algorithm>
#include <vector>
#include <string>
#include <complex>
#include <stack>
#include <queue>
#include <list>
#include <utility>
#include <set>
using namespace std;

int main(){
    int n;
    cin >> n;
    int g[110][110];
    int i, j;
    int u, k, v;
    int dist[110];
    bool visited[110];
    
    for(i = 0; i < n; i++){
        dist[i] = -1;
        for(j = 0; j < n; j++){
            g[i][j] = 0;
        }
    }
    
    for(i = 0; i < n; i++){
        cin >> u >> k;
        u--;
        for(j = 0; j < k; j++){
            cin >> v;
            v--;
            g[u][v] = 1;
        }
    }
    
    queue<int> q1, q2;
    q1.push(0);
    
    for(i = 0; q1.size(); i++){
        while(!q1.empty()){
            int p = q1.front();
            q1.pop();
            
            if(visited[p]) continue;
            visited[p] = true;
            
            dist[p] = i;
            
            for(j = 0; j < n; j++){
                if(g[p][j]){
                    q2.push(j);
                }
            }
        }
        q1 = q2;
        q2 = queue<int>();
    }
    
    for(i = 0; i < n; i++){
        cout << i+1 << " " << dist[i] << endl;
    }
}