Go: package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)

	g := make([][]int, n+1)
	d := make([]int, n+1)
	for i := 0; i < n; i++ {
		var u,k int
		fmt.Scan(&u)
		fmt.Scan(&k)
		g[u] = make([]int, k)
		for j := 0; j < k; j++ {
			fmt.Scan(&g[u][j])
		}

		d[i+1] = -1
	}

	q := [][]int{}
	q = append(q, []int{1, 0})
	for len(q) > 0 {
		pop := q[0]
		if len(q) > 1 {
			q = q[1:]
		} else {
			q = [][]int{}
		}
		if d[pop[0]] >= 0 {
			continue
		}
		d[pop[0]] = pop[1]

		for j := 0; j < len(g[pop[0]]); j++ {
			q = append(q, []int{g[pop[0]][j], pop[1]+1})
		}
	}

	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d\n", i, d[i])
	}
}

C++: #include<algorithm>
#include<bitset>
#include<cassert>
#include<cfloat>
#include<climits>
#include<cmath>
#include<deque>
#include<functional>
#include<iomanip>
#include<iostream>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<string>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<vector>
#include<complex>
#include<list>
#include<cstdio>

#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define FORR(i, m, n) for(int i = m;i >= n;i--)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define llong long long
#define pb(a) push_back(a)


using namespace std;

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




const int INF = 1e9 + 7;


/******************************************************************************************/



vector<int> G[105];
int dist[105];


int main() {

	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(10);

	int n;
	cin >> n;

	for (int i = 0; i < 105; i++)
	{
		dist[i] = INF;
	}

	for (int i = 0; i < n; i++)
	{
		int node, out;
		cin >> node >> out;
		for (int j = 0; j < out; j++)
		{
			int c;
			cin >> c;
			G[node].push_back(c);
		}
	}


	queue<int> que;

	que.push(1);
	dist[1] = 0;

	while (!que.empty()) {

		int now = que.front();
		que.pop();

		if (dist[now] == INF)continue;
		for (int nxt : G[now]) {

			if (dist[nxt] > dist[now] + 1) {
				dist[nxt] = dist[now] + 1;
				que.push(nxt);
			}
		}
	}

	for (int i = 1; i <= n; i++)
	{
		if (dist[i] == INF) {
			cout << i << " " << -1 << endl;
		}
		else
		{
			cout << i << " " << 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];

void bfs(int s) {
	int i, u, v;
	queue<int> q;
	q.push(s);
	for ( i = 0; i < n; i++ ) d[i] = INFTY;
	d[s] = 0;

	while ( !q.empty() ) {
		u = q.frout();
		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 <vector>
#include <queue>

#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;
const int MAX_N = 100;
vector<int> G[MAX_N];
vector<bool> seen(MAX_N, false);

int main()
{
    int N;
    cin >> N;
    rep(i, N)
    {
        int id, u;
        cin >> id >> u;
        rep(j, u)
        {
            int target;
            cin >> target;
            target--;
            G[i].push_back(target);
        }
    }

    // 最短距離を算出
    queue<int> que;
    que.push(0);

    int distance = 0;
    int d[N];
    fill_n(d, N, -1);
    d[0] = 0;
    seen[0] = true;
    while (!que.empty())
    {
        int origin = que.front();
        int distance = d[origin];
        que.pop();
        for (int target : G[origin])
        {
            if (!seen[target])
            {
                seen[target] = true;
                d[target] = distance + 1;
                que.push(target);
            }
        }
    }

    rep(i, N)
    {
        int id = i + 1;
        cout << id << " " << d[i] << endl;
    }

    return 0;
}

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

const int MAX_N = 100;
int to[MAX_N][MAX_N];
int ans[MAX_N];
bool visited[MAX_N];

int main() {
  int N;
  cin >> N;
  for (int i=0; i<N; i++) {
    for (int j=0; j<N; j++) {
      to[i][j] = -1;
    }
    ans[i] = -1;
    visited[i] = false;
  }
  for (int i=0; i<N; i++) {
    int tmp, n;
    cin >> tmp >> n;
    for (int j=0; j<n; j++) {
      int t;
      cin >> t; t--;
      to[i][j] = t;
    }
  }

  queue<pair<int, int> > que;
  que.push(make_pair(0, 0));
  while (!que.empty()) {
    pair<int, int> tmp = que.front(); que.pop();
    int x = tmp.first, depth = tmp.second;
    if (ans[x] == -1) {
      ans[x] = depth;
    } else {
      ans[x] = min(ans[x], depth);
    }
    for (int i=0; to[x][i] != -1; i++) {
      que.push(make_pair(to[x][i], depth + 1));
    }
  }

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

C++: #include <iostream> 
#include <queue>
#define NODE_NUM 100
using namespace std;

int v_num, v_degree, v, v_id;
int adj_M[NODE_NUM][NODE_NUM], Distance[NODE_NUM], visit_state[NODE_NUM];
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;

void BreadthFirstSearch(int node) 
{
    queue<int> Q;
    Q.push(node);
    Distance[node] = 0;
    visit_state[node] = GRAY;

    while(! Q.empty())
    {
        int cur_node = Q.front();
        for (int i = 0; i < v_num; ++i) 
        {
            if (adj_M[cur_node][i] == 1 && visit_state[i] == WHITE) 
            {
                Q.push(i);
                visit_state[i] = GRAY;
                Distance[i] = Distance[cur_node] + 1;
            } 
        } 
        Q.pop();
        visit_state[cur_node] = BLACK;
    }
}

int main() 
{
    cin >> v_num;

    // init
    for (int i = 0; i < v_num; ++i) 
    {
        for (int j = 0; j < v_num; ++j) 
        {
            adj_M[i][j] = 0;
        }
        Distance[i] = -1;
        visit_state[i] = WHITE;
    }

    for (int i = 0; i < v_num; ++i) 
    {
        cin >> v_id >> v_degree;
        v_id--;
        for (int i = 0; i < v_degree; ++i) 
        {
            cin >> v;
            adj_M[v_id][v-1] = 1;
        }
    }

    BreadthFirstSearch(0);

    for (int i = 0; i < v_num; ++i) cout << i+1 << " " << Distance[i] << endl;
}

C++: #include<iostream>

#include<algorithm>

#include<vector>

#include<cassert>

#include<cstdio>

#include<queue>



using namespace std;



int N, G[100][100], V[100], D[100];//G:２頂点,V:次数,D:距離



void bfs(int src){

	queue<int> Q;

	Q.push(src);

	fill(D, D + N, -1);

	D[src] = 0;

	while (!Q.empty()){

		int cur = Q.front();

		Q.pop();

		for (int k = 0; k < N; k++){

			if (G[cur][k] == 1 && D[k] == -1){

				D[k] = D[cur] + 1;

				Q.push(k);

			}

		}

	}

	for (int l = 0; l < N; l++){

		cerr << l + 1 << " " << D[l] << endl;

	}

}



int main(){

	scanf_s("%d", &N);

	int id, c;

	for (int i = 0; i < N; i++){

		scanf_s("%d", &id); id--;//配列は0から始まるので、頂点番号を-1して考える。

		scanf_s("%d", V + id);

		for (int j = 0; j < V[id]; j++){

			scanf_s("%d", &c); c--;//配列は0から始まるので、頂点番号を-1して考える。

			G[id][c] = 1;

		}

	}//データの読み込み完了。

	bfs(0);

}