Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

func pop(q *[]int) int {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

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

#define N 100
#define INFTY (1<<30)
int n,m[N][N],d[N];//通过距离管理访问状态(color)

void bfs(int s) //广搜
{
    queue<int> q;
    q.push(s);
    for(int i=0;i<n;i++) d[i]=INFTY; //注意这里不能用memset
    d[s]=0; //初始化

    while(!q.empty())
    {
        int u=q.front();q.pop();
        for(int v=0;v<n;v++)
        {
            if(m[u][v]&&d[v]==INFTY) //如果有节点与u相邻且该节点没有被访问过
            {
                d[v]=d[u]+1; //距离+1
                q.push(v); //将该节点加入待访问队列中
            }
        }
    }

    for(int i=0;i<n;i++)
        cout<<i+1<<" "<<(d[i]==INFTY ? -1 : d[i])<<endl; //注意这里要用括号
}

int main()
{
    int u,k,v;
    cin>>n;
    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++: #include <bits/stdc++.h>
using namespace std;

int main()
{
int n,u,k,v;scanf("%d",&n);
vector<vector<int>> G(n);
for(int i=0;i<n;i++)
{
scanf("%d %d",&u,&k);
for(int j=0;j<k;j++)
{
scanf("%d",&v);
G[u-1].push_back(v-1);
}
}
vector<int> dis(n,-1);
queue<int> que;
dis[0]=0;
que.push(0);
while(!que.empty())
{
v=que.front();
que.pop();
for(int nv : G[v])
{
if(dis[nv]!=-1)continue;
dis[nv]=dis[v]+1;
que.push(nv);
}
}
for(int i=0;i<n;i++)printf("%d %d\n",i+1,dis[i]);
}

C++: #include <algorithm>
#include <iostream>
#include <string>
#include <cstring>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <deque>
#include <iomanip>
#include <limits>
#include <map>
#include <queue>
#include <stack>
#include <vector>

#define FOR(i,k,n) for(int (i) = (k); (i) < (n); ++(i))
#define rep(i,n) FOR(i,0,n)
#define pb push_back
#define all(v) begin(v), end(v)
#define debug(x) cerr << #x << ": " << x << endl
#define debug2(x,y) cerr << #x << ": " << x << ", " << #y << ": " << y << endl

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector< vector<int> > vvi;
template<class T> using vv=vector< vector<T> >;
typedef deque<int> di;
typedef deque< deque<int> > ddi;


int main() {
    int n;
    cin >> n;
    vi vlist[101];
    rep(i,n) {
        int u,k;
        cin >> u >> k;
        rep(i,k) {
            int v;
            cin >> v;
            vlist[u].pb(v);
        }
    }

    queue<int> Q;
    int count[101];
    Q.push(1);

    while(!Q.empty()) {
        int i = Q.front();
        Q.pop();
        
        rep(j,vlist[i].size()) {
            if(count[vlist[i][j]] == 0 && vlist[i][j] != 1) {
                count[vlist[i][j]] = count[i] + 1;
                Q.push(vlist[i][j]);
            }
        }
    }
    FOR(i,1,n+1) {
        if(i != 1 && count[i] == 0) {
            cout << i << " " << -1 << endl;
        } else {
            cout << i << " " << count[i] << endl;
        }
    }

	return 0;
}

C++: #include<iostream>
#include<queue>
using namespace std;
const int MAXN = 105;
const int INF = 1<<21;
int a[105][105];
int d[MAXN];
int n;


void bfs(int s)
{
	for(int i = 0; i < n; i++)
	{
		d[i] = INF;
	}
	queue<int> q;
	q.push(s);
	d[s] = 0;
	
	int u;
	while(!q.empty())
	{
		u = q.front(); q.pop();
		for(int v = 0; v < n; v++)
		{
			if(d[v] != INF)
				continue;
			if(a[u][v] == 0)
				continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	
	for(int i = 0; i < n; i++)
	{
		cout << i+1 << " " << d[i] << endl;
	}
}

int main ()
{
	int u, v, k;
	cin >> n;
	for(int i = 0; i < n; i++)
	{
		cin >> u >> k;
		u--;
		for(int j = 0; j < k; j++)
		{
			cin >> v;
			v--;
			a[u][v] = 1;
		}
	}
	bfs(0);
	return 0;
}