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 <cstdio>
#include <iostream>
#include <queue>

using namespace std;

int main() {
	int n;
	scanf("%d", &n);

	bool G[n + 1][n + 1];
	for (int i = 0; i <= n; ++i) {
		for (int j = 0; j <= n; ++j)
			G[i][j] = false;
	}

	for (int i = 0; i < n; ++i) {
		int u, k;
		scanf("%d %d", &u, &k);
		for (int j = 0; j < k; ++j) {
			int v;
			scanf("%d", &v);
			G[u][v] = true;
		}
	}

	int d[n + 1];
	for (int i = 0; i <= n; ++i)
		d[i] = -1;

	int color[n + 1];
	int WHITE = 0;
	int GRAY = 1;
	int BLACK = 2;
	for (int i = 0; i <= n; ++i)
		color[i] = WHITE;

	queue<int> Q;
	Q.push(1);
	d[1] = 0;
	color[1] = GRAY;

	while (Q.size() != 0) {
		int v = Q.front();
		for (int i = 1; i <= n; ++i) {
			if (G[v][i] && color[i] == WHITE) {
				Q.push(i);
				color[i] = GRAY;
				d[i] = d[v] + 1;
			}
		}
		Q.pop();
		color[v] = BLACK;
	}
	for (int i = 1; i <= n; ++i) {
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string.h>
#include<queue>
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define MAX 105
using namespace std;
int N;
//int M[MAX][MAX];
vector<int> V[MAX];
int D[MAX];
void BFS(int u)
{
	queue<int> Q;
	Q.push(u);
	D[u]=0;
	while(!Q.empty())
	{
		int i=Q.front();
		Q.pop();
		/*FOR(j,1,N)
			if(M[i][j]&&D[j]==MAX)
			{
				Q.push(j);
				D[j]=D[i]+1;
			}
		*/
		for(int j=0;j<V[i].size();j++)
			if(D[V[i][j]]==MAX)
			{
				Q.push(V[i][j]);
				D[V[i][j]]=D[i]+1;
			}
	}
	FOR(i,1,N)
		printf("%d %d\n",i,(D[i]==MAX)?-1:D[i]);
		//cout<<i<<" "<<((D[i]==MAX)?(-1):D[i])<<"\n";
}
int main()
{
	//memset(M,0,sizeof(M));
	scanf("%d",&N);
	FOR(i,1,N)
		D[i]=MAX;
	int u,k,v;
	FOR(i,1,N)
	{
		scanf("%d %d",&u,&k);
		FOR(j,1,k)
		{
			scanf("%d",&v);
			V[u].push_back(v);
		}
	}
	BFS(1);
	return 0;
}