Go: package main

import "fmt"

type container struct {
	data []int
}

func (c *container) queue(v int) {
	c.data = append(c.data, v)
}
func (c *container) dequeue(p *int) bool {
	if p == nil || len(c.data) == 0 {
		return false
	}
	*p = c.data[0]
	c.data = c.data[1:len(c.data)]
	return true
}

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

	var q container
	d[1] = 0
	q.queue(1)

for len(q.data) > 0  { // 幅優先探索
		var v int
		q.dequeue(&v)
		for i := 0; i < len(g[v]); i++ {
			nv := g[v][i]
		if d[nv] == -1 { // 未訪問
				q.queue(nv)
				d[nv] = d[v] + 1
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d\n", i, d[i])
	}
}

C++: #include <bits/stdc++.h>
using namespace std;

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

    int n;
    cin >> n;

    vector<int> G[n];
    for(int i = 0; i < n; i++){
        int p, k;
        cin >> p >> k;
        for(int j = 0; j < k; j++){
            int a;
            cin >> a;
            G[p - 1].push_back(a - 1);
        }
    }

    vector<int> D(n, 1e9);
    D[0] = 0;
    queue<int> q;
    q.push(0);

    while(!q.empty()){
        int now = q.front();
        q.pop();

        for(int i = 0; i < G[now].size(); i++){
            int to = G[now][i];
            if(D[now] + 1 < D[to]){
                D[to] = D[now] + 1;
                q.push(to);
            }
        }
    }

    for(int i = 0; i < n; i++){
        cout << i + 1 << ' ' << (D[i] == 1e9 ? -1 : D[i]) << endl;
    }

    return 0;
}

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

using namespace std;
typedef long long ll;

#define INF (long long)(1e9+7)
#define REP(i,n) for(ll i = 0; i < n; i++)
#define REP1(i,n) for(ll i = 1; i <= n; i++)

using Graph = vector<vector<int>>;


int main(void)
{
  int n;
  cin >> n;
  Graph G(n);
  int u, k;
  REP(j, n) {
    cin >> u >> k;
    u--;
    REP(i, k) {
      int v;
      cin >> v;
      v--;
      G[u].push_back(v);
      //      G[v].push_back(u);
    }
  }

  vector<int> dist(n, -1);
  queue<int> que;

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

  while(!que.empty()) {
    int v = que.front(); que.pop();

    for(int nv : G[v]) {
      if(dist[nv] != -1) continue;

      dist[nv] = dist[v] + 1;
      que.push(nv);
    }
  }
  REP(i, n) cout << i + 1 << " " << dist[i] << endl;

}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <stack>
#include <cstdlib>
#include <queue>
#include <vector>
#include <set>

using namespace std;
int n,m,l,p;
bool a[100][100];
int D[100];
void bfs( int src) {
	queue<int> Q;
	Q.push(src);
	D[src]=0;
	while( ! Q.empty() ) {
		int cur = Q.front();
		Q.pop();
		for(int dst = 0; dst < n; dst++ ) {
			if( D[dst] == 0 && a[cur][dst] == 1 ) {
				D[dst] = D[cur] + 1;
				Q.push(dst);
			}
		}
	}
	for (int i = 0; i < n;i++) {
	cerr << i+1 <<  " " << D[i] <<  endl;
	}
}

int main() {
	cin >> n;
	for ( int i = 0;i < n;i++) {
		D[i] = 0;
		for(int j= 0; j < n;j++) {
			a[i][j] = 0;
		}
	}
	for (int i = 0;i < n; i++){
		cin >> m;
		cin >> l;
		for(int j = 0; j < l;j++) {
			cin >> p;
			a[m-1][p-1] = 1;
		}
	}
	bfs(0);
}