Go: package main

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

var distance []int

type queue struct {
	q    []int
	head int
	tail int
}

func (q *queue) push(n int) {
	q.q[q.tail] = n
	q.tail++
}

func (q *queue) pop() int {
	q.head++
	return q.q[q.head-1]
}

func (q *queue) isEmpty() bool {
	return q.head == q.tail
}

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func bfs(graph [][]int, s int) {
	distance = make([]int, len(graph))

	infty := -1
	for i := 0; i < len(distance); i++ {
		distance[i] = infty
	}
	distance[s] = 0

	q := &queue{make([]int, 1000), 0, 0}
	q.push(s)

	for !q.isEmpty() {
		u := q.pop()
		for i := 0; i < len(graph); i++ {
			if graph[u][i] == 0 {
				continue // u, i間に辺がない場合
			}
			if distance[i] != infty {
				continue // 訪問済みの場合
			}
			// 訪問するnodeの始点からの距離を設定し、訪問キューに入れる
			distance[i] = distance[u] + 1
			q.push(i)
		}
	}

	// print distance
	for i, d := range distance {
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	adj := makeAdjList()
	bfs(adj, 0)
}

C++: #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))
#define mem(a, p) memset(a, p, 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();
	mem(vis, -1);
	return;
}

bool check(int x, int y)
{
	if(mtx[x][y] && vis[y] == -1)
		return true;
	return false;
}

void Bfs(void)
{
	int cnt = 1;
	q.push(1);
	vis[1] = 0;
	while(!q.empty())
	{
		int cur = q.front();
		q.pop();
		rep(1, n)
		{
			if(check(cur, i))
			{
				q.push(i);
				vis[i] = vis[cur] + 1;
				cnt++;
				if(cnt == n)
					return;
			}
		}
	}
	return;
}

int main()
{
	while(~scanf("%d", &n))
	{
		init();
		rep(1, n)
		{
			int row;
			scanf("%d", &row);
			int num;
			scanf("%d", &num);
			while(num--)
			{
				int tmp;
				scanf("%d", &tmp);
				mtx[row][tmp] = true;
			}
		}
		
		Bfs();
		
		rep(1, n)
			printf("%d %d\n", i, vis[i]);
	}
	return 0;
}

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

using namespace std;

#define MAX 100
int INFTY = (1<<21);
int num,M[MAX][MAX];
int d[MAX];

void bfs(int s){
  queue<int> q;
  q.push(s);
  int u,i,v;
  for( i = 0; i < num; i++){
    //d[i] = INFINITY;
    d[i] = INFTY;
  }
  d[s] = 0;
  while( !q.empty()){
    u = q.front();
    q.pop();
  for(v = 0; v < num; v++){
    if( M[u][v] == 0){
      continue;
    }
    //if( d[v] != INFINITY){
    if( d[v] != INFTY){
      continue;
    }
    d[v] = d[u]+1;
    q.push(v);
  }
  }
  for(i = 0; i < num; i++){
    //cout << i+1 << " ";
    /*
    if(d[i] == INFINITY){
      cout << (-1);
    }
    else{
      cout << d[i] << endl;
    } 
    */
    cout << i+1 << " " << ( (d[i] == INFTY) ? (-1) : d[i] ) << endl;
  }
}

int main(){
  int u,k,v,i,j;
  cin >> num;
  for(i = 0; i < num; i++){
    for(j = 0; j < num; j++){
      M[i][j] = 0;
    }
  }

  for(i = 0; i < num; i++){
    cin >> u >> k;;
    u--;
    for(j = 0; j < k; j++){
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }
  bfs(0);
  return 0;
}

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

using namespace std;

typedef long long int ll;
typedef pair<ll, ll> pll;

#define FOR(i, n, m) for(ll (i)=(m);(i)<(n);++(i))
#define REP(i, n) FOR(i,n,0)
#define OF64 std::setprecision(10)

const ll MOD = 1000000007;
const ll INF = (ll) 1e15;

struct Vertex {
    vector<ll> node;
};

Vertex V[105];
ll C[105];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll N;
    cin >> N;
    REP(i, N) {
        C[i] = INF;
    }
    REP(i, N) {
        ll n, k;
        cin >> n >> k;
        n--;
        REP(_, k) {
            ll v;
            cin >> v;
            v--;
            V[n].node.push_back(v);
        }
    }

    queue<pll> q;
    q.push(pll(0, 0));
    C[0] = 0;
    while (!q.empty()) {
        pll t = q.front();
        q.pop();
        ll cost = t.second + 1;
        for (auto &n:V[t.first].node) {
            if (C[n] <= cost)
                continue;
            C[n] = cost;
            q.push(pll(n, cost));
        }
    }

    REP(i, N) {
        cout << i + 1 << " ";
        if (C[i] == INF)
            cout << -1;
        else
            cout << C[i];
        cout << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <queue>

using ll = long long;
using namespace std;
int n, A[100][100];
int d[100];
/* initialize */

void bfs(int s){
    queue<int> q;
    q.push(s);
    for (int i = 0; i < n; ++i) d[i] = 1<<30;
    d[s] = 0;
    int u;
    while(!q.empty()){
        u = q.front(); q.pop();
        for (int i = 0; i < n; ++i) {
            if ( A[u][i] == 0 ) continue;
            if (d[i] != 1<<30) continue;
            d[i] = d[u] + 1;
            q.push(i);
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << i+1 << " " << ( (d[i] == 1<<30) ? -1 : d[i]) << "\n";
    }
}
/* main */
int main() {
    int u, k, v;
    cin >> n;
    for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j) A[i][j] = 0;
    for (int i = 0; i < n; ++i) {
        cin >> u >> k;
        for (int j = 0; j < k; ++j) {
            cin >> v;
            A[u-1][v-1] = 1;
        }
    }
    bfs(0);
    return 0;
}