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<queue>

using namespace std;

static const int N = 100;

int n,d[N],M[N][N];//d[]...?§??????????????????¢(-1?????°?????????)???M[][]?????£??\???????????§????????????

void dfs(int r) {
	queue<int> q;//queue??§?????????
	q.push(r);//?§?????????£??\
	for (int i = 0; i < n; i++) d[i] = -1;//??????????????????
	d[r] = 0;//?§????????????¢???0

	int u;
	while (!q.empty()) {//??¢?´¢???????????§??°?????????
		u = q.front();//u????????\?????????????????¢?´¢???????????£?????????????????£??\
		q.pop();//?????\???????????????????´????????????????

		for (int v = 0; v < n; v++) {//??£??\????????????????????????
			if (M[u][v] == 0) continue;//?§??????¨??????????????§?????°?????????????????´???????????????
			if (d[v] != -1) continue;//?§??????¨????????¢???????????£??????????????¢?´¢???????????£??????????????´??????????????????
			d[v] = d[u] + 1;//??????u????§??????¨??£??\?????????????????????????????¢1???1?????????????????????????????????+1???
			q.push(v);//?????\??????v?????????
		}
	}
	for (int i = 0; i < n; i++) {
		cout<<i+1<<" "<<d[i]<<endl;//??????
	}
}

int main() {
	int u, p, v;
	cin >> n;
	for (int i = 0; i < n; i++) {//?????????(d[]?????¢????????????dfs??§?±??????????????????§????????????????????????)
		for (int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}

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

	dfs(0);//??????0????§??????¨??????

	return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <cstdio>
#include <utility>
#include <string>
#include <cmath>
#include <cstdlib>
#include <cstring>

using namespace std;

typedef uint64_t u64;
typedef int64_t s64;
typedef uint32_t u32;
typedef int32_t s32;
typedef vector<s32> vs32;
typedef vector<u32> vu32;
typedef vector<s64> vs64;
typedef vector<u64> vu64;

const double PI=3.14159265358979323846;

#define MAX(x, y) ((x) < (y) ? (y) : (x))
#define MIN(x, y) ((x) > (y) ? (y) : (x))

#define rep(i, N) for(int i = 0; i < N; ++i)

#define CEIL(x, y) (((x) + (y) - 1) / (y))
#define MOD 1000000007ULL

class DirectedGraph
{
public:
    DirectedGraph() {}
    DirectedGraph(int n)
    : g(vector< vs32 >(n)), dist(vs32(n, -1))
    {}
    ~DirectedGraph() {}

    void bfs(int u)
    {
        int d = 0;
        dist[u]  = 0;
        queue<int> q;
        q.push(u);
        while (!q.empty())
        {
            int n = q.size();
            ++d;
            rep (i, n)
            {
                int v = q.front();
                q.pop();
                rep (j, g[v].size())
                {
                    if (dist[g[v][j]] < 0)
                    {
                        dist[g[v][j]] = d;
                        q.push(g[v][j]);
                    }
                }
            }
        }
    }

    vector< vs32 > g;
    vs32 dist;
};

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    DirectedGraph dg(n);
    int u, v;
    int c;
    rep (i, n)
    {
        cin >> u >> c;
        --u;
        dg.g[u].resize(c);
        rep (j, c)
        {
            cin >> v;
            --v;
            dg.g[u][j] = v;
        }
    }

    dg.bfs(0);

    rep (i, n)
    {
        cout << i + 1 << " " << dg.dist[i] << "\n";
    }
    return 0;
}

C++: #include <cstdio>
#include <queue>
using namespace std;
#define MAX_N 100

int g[MAX_N+1][MAX_N+1];
int d[MAX_N+1];
bool visited[MAX_N+1];
queue<int> que;

int n;
int t = 1;

void bfs(int id) {
  visited[id] = true;
  que.push(id);
  while(!que.empty()) {
    int v = que.front(); que.pop();
    queue<int> next_que;
    for(int u=1;u<=n;u++) {
      if(g[v][u]!=0 && !visited[u]) {
        visited[u]=true;
        next_que.push(u);
        d[u] = t;
      }
    }
    if(que.empty()){
      que = next_que;
      t++;
    }
  }
}

int main() {
  scanf("%d\n",&n);
  int u,k,v;
  for(int i=0;i<n;i++) {
    scanf("%d %d ",&u,&k);
    for(int j=0;j<k;j++) {
      scanf("%d ",&v);
      g[u][v] = 1;
    }
  }
  bfs(1);
  for(int i=1;i<=n;i++) {
    if(visited[i])
      printf("%d %d\n",i,d[i]);
    else
      printf("%d -1\n",i);
  }
}

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

void BFS(int s, const vector<vector<int> >& G, vector<int>& D){
    queue<int> Q;
    Q.push(s);
    D[s] = 0;
    while (!Q.empty()) {
        int f = Q.front();
        for (int i = 0; i < G[f].size(); i++) {
            if (D[G[f][i]] == -1) {
                D[G[f][i]] = D[f] + 1;
                Q.push(G[f][i]);
            }
        }
        Q.pop();
    }
}

int main(){
    int n;
    cin >> n;
    vector<vector<int> > G(n + 1);
    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].push_back(v);
        }
    }
    vector<int> D(n + 1, -1);
    BFS(1, G, D);
    for (int i = 1; i <= n; i++) {
        cout << i << " " << D[i] << endl;
    }
    return 0;
}