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>

#define FOR(i,k,n) for (int (i)=(k); (i)<(n); ++(i))
#define REP(i,n) FOR(i,0,n)
using namespace std;

int main(){
    int n,u,k,v,src=0;
    cin >> n;
    int D[n],g[n][n];
    REP(i,n){
        D[i] = 0;
        REP(j,n){
            g[i][j] = 0;
        }    
    }
    REP(i,n){ 
        cin >> u >> k;
            REP(j,k){
                cin >> v;
                g[v-1][u-1] = 1;
            }
    }

    queue<int> Q;
    Q.push(src);
    while (!Q.empty()) {
        int cur = Q.front();
        Q.pop();
            REP(i,n){
                if(g[i][cur] == 1 && D[i] == 0){
                    D[i] = D[cur] + 1;
                    Q.push(i);
                }
            }
    }

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

C++: #include <iostream>
#include <queue>
#include <assert.h>
#define INF 100000000
#define MAX_V 100
using namespace std;

int adjacencyMatrix[MAX_V][MAX_V] = {};
int d[MAX_V];
int V;

void bfs(int start)
{
    queue<int> Q;
    Q.push(start);

    for (int i = 0; i < V; ++i)
        d[i] = INF;

    d[start] = 0;

    while (!Q.empty()) {
        int u = Q.front();
        Q.pop();
        for (int i = 0; i < V; ++i) {
            if (d[i] != INF) continue;
            if (adjacencyMatrix[u][i] == 1)
                d[i] = d[u] + 1;
            Q.push(i);
        }
    }
    return;
}

int main()
{
    cin >> V;

    for (int i = 0; i < V; ++i) {
        int u, k;
        cin >> u >> k;
        assert(u = i + 1);
        for (int j = 0; j < k; ++j) {
            int tmp;
            cin >> tmp;
            adjacencyMatrix[i][tmp - 1] = 1;
        }
    }

    bfs(0);

    for (int i = 0; i < V; ++i)
        cout << i + 1 << " " << d[i] << endl;

    return 0;
}

C++: //
// Created by 李青坪 on 2018/11/3.
//

#include <cstdio>
#include <algorithm>
#include <queue>

#define MAXN 101
using namespace std;
int n;
int graph[MAXN][MAXN];
int dist[MAXN];
queue<int > q;

void init(){
    fill(dist, dist+MAXN, -1);
    dist[1] = 0;
}

void bfs(int i){
    for (int j = 1; j <= n; ++j) {
        if (graph[i][j] == 1){
            q.push(j);
            dist[j] = dist[j] >= 0 ? min(dist[j], dist[i] + 1): dist[i] + 1;
        }
    }
    while (!q.empty()){
        int next = q.front();
        q.pop();
        bfs(next);
    }
}

int main(){
    scanf("%d", &n);
    int u, k;
    for (int i = 0; i < n; ++i) {
        scanf("%d %d", &u, &k);
        int node;
        for (int j = 0; j < k; ++j) {
            scanf("%d", &node);
            graph[u][node] = 1;
        }
    }
    init();
    bfs(1);
    for (int l = 1; l <= n; ++l) {
        printf("%d %d\n", l, dist[l]);
    }
}
/*
5
1 2 2 4
2 1 4
3 0
4 1 3
5 1 4
 */

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++: 
#if 1
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <stack>
#include <array>
#include <deque>
#include <algorithm>
#include <utility>
#include <cstdint>
#include <functional>
#include <iomanip>
#include <numeric>
#include <assert.h>
#include <bitset>
#include <list>

auto& in = std::cin;
auto& out = std::cout;
#define all_range(C) std::begin(C), std::end(C)
const double PI = 3.141592653589793238462643383279502884197169399375105820974944;

namespace std {
	template<class Ty, size_t Ix>
	struct rank<std::array<Ty,Ix>>
		: integral_constant<size_t, rank<Ty>::value + 1>
	{	// determine number of dimensions of array _Ty
	};
}

template<typename T, typename U>
std::enable_if_t<std::rank<T>::value == 0> fill_all(T& arr, const U& v) {
	arr = v;
}
template<typename ARR, typename U>
std::enable_if_t<std::rank<ARR>::value != 0> fill_all(ARR& arr, const U& v) {
	for (auto& i : arr) {
		fill_all(i, v);
	}
}

int32_t N;
int32_t INF = 100100;
std::array<std::array<int32_t, 100>,100> dp;
std::array<std::array<int32_t, 100>, 100> dp2;
void WF() {
	for (size_t k = 0; k < N; k++)
		for (size_t i = 0; i < N; i++)
			for (size_t j = 0; j < N; j++)
	{
		dp[i][j] = std::min(dp[i][j], dp[i][k] + dp[k][j]);
	}
}

int main()
{
	using std::endl;
	in.sync_with_stdio(false);
	out.sync_with_stdio(false);
	in.tie(nullptr);
	out.tie(nullptr);

	fill_all(dp, INF);
	in >> N;
	for (int32_t i = 0; i < N; i++)
	{
		int from,m;
		in >> from >> m; --from;
		dp[from][from] = 0;
		for (int32_t j = 0; j < m; j++)
		{
			int to;
			in >> to; --to;
			dp[from][to] = 1;
		}
	}

	WF();
	dp2 = dp;
	WF();
		for (int32_t i = 0; i < N; i++)
		{
			out << i + 1 << ' ' << (dp[0][i]!=INF? dp[0][i]:-1) << endl;
		}

	return 0;
}
#endif