Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve
const INFTY = (1 << 21)
const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 頂点1から頂点iまでの距離
var color, d [MAX]int

func bfs(s int) {
	var q []int
	q = append(q, s)
	for i := 0; i < n; i++ {
		d[i] = INFTY
	}
	//sは開始点なので、0をいれる
	d[s] = 0

	//キューが空になるまで、以下を繰り返す
	for len(q) > 0 {
		u := q[0]
		q = q[1:]
		for v := 0; v < n; v++ {
			if M[u][v] == 0 {
				continue
			}
			if d[v] != INFTY {
				continue
			}
			d[v] = d[u] + 1
			q = append(q, v)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Printf("%d ", i+1)
		if d[i] == INFTY {
			fmt.Printf("%d\n", -1)
		} else {
			fmt.Printf("%d\n", d[i])
		}
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	bfs(0)

}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#define Lens 105
using namespace std;
int N;
int A[Lens][Lens];
int d[Lens];
char c[Lens];
queue<int> Q;

int main()
{
	cin >> N;
	Q.push(1);
	for (int i = 1; i <= N; i++)
	{
		int k, n;
		cin >> k >> n;
		c[k] = 'w';
		for (int i = 0; i < n; i++)
		{
			int j;
			cin >> j;
			A[k][j] = 1;
		}
	}
	while (Q.size())
	{
		int i = Q.front();
		Q.pop();
		for(int j=1;j<=N;j++)
		{
			if (A[i][j] == 1 && c[j] == 'w')
			{
				c[j] = 'g';
				d[j] = d[i] + 1;
				Q.push(j);
			}	 
		}
	}
	for (int i = 2; i <= N; i++)
	{
		if (c[i] == 'w')
			d[i] = -1;
	}	
	for (int i = 1; i <= N; i++)
	{
		cout << i << ' ' << d[i] << endl;
	}
	return 0;
}

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

const int INF = 1 << 10;
const int MAX_N = 110;
const int DONE = 2;
const int TOUCHED = 1;
const int NOT_TOUCHED = 0;
int G[MAX_N][MAX_N];
int D[MAX_N];
int V[110];

int main() {
  int n, i, j, u, k, v, d;
  queue<int> q;

  cin >> n;
  for (i = 0; i < n; ++i) {
    D[i] = INF;
  }

  for (i = 0; i < n; ++i) {
    cin >> u >> k;
    for (j = 0; j < k; ++j) {
      cin >> v;
      G[u - 1][v - 1] = 1;
    }
  }

  D[0] = 0;
  V[0] = TOUCHED;
  q.push(0);
  while (!q.empty()) {
    i = q.front(); q.pop();
    for (j = 0; j < n; ++j) {
      if (G[i][j] && V[j] != DONE) {
        if (V[j] == NOT_TOUCHED) {
          V[j] = TOUCHED;
          q.push(j);
        }
        D[j] = min(D[j], D[i] + 1);
      }
    }
    V[i] = DONE;
  }

  for (i = 0; i < n; ++i) {
    d = D[i] == INF ? -1 : D[i];
    cout << i + 1 << ' ' << d << '\n';
  }

  return 0;
}

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

using i64 = int64_t;

using Graph = vector<vector<int>>;

int main(){
    int n;
    cin >> n;
    Graph graph(n+1, vector<int>());
    for(int i=0;i<n;++i){
        int u, k;
        cin >> u >> k;
        for(int j=0;j<k;++j){
            int v;
            cin >> v;
            graph[u].push_back(v);

        }
    }

    vector<int> mini(n+1, 200);
    queue<pair<int, int>> que;
    mini[1] = 0;
    que.push({1, 0});
    while(!que.empty()){
        auto cur = que.front(); que.pop();
        for(auto to: graph[cur.first]){
            int cost = cur.second + 1;
            if(mini[to] <= cost)continue;
            mini[to] = cost;
            que.push({to, cost});
        }
    }

    for(int i=1;i<=n;++i){
        cout << i << " " << (mini[i] < 200 ? mini[i] : -1) << endl;
    }

    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (int)(n); i++)
using namespace std;
using Graph = vector<vector<int>>;
template<class T> bool chmin(T &a, T b) {if(a>b) {a=b;return 1;}return 0;}
const int inf = 1e8;

int main() {
    int n;
    cin >> n;
    Graph g(n);
    rep(i,n) {
        int id,k;
        cin >> id >> k;
        id--;
        rep(j,k) {
            int v;
            cin >> v;
            v--;
            g[id].push_back(v);
        }
    }
    vector<int> d(n);
    rep(i,n) d[i] = inf;
    d[0] = 0;
    queue<int> q;
    q.push(0);
    while (!q.empty()) {
        int v = q.front(); q.pop();
        for (int n_v: g[v]) if (chmin(d[n_v],d[v]+1)) q.push(n_v);       
    };
    rep(i,n) if (d[i] == inf) d[i] = -1;
    rep(i,n) cout << i+1 << " " << d[i] << endl;
}

C++: #include<cstdio>
#include<queue>
#define MAX 100
using namespace std;
int n, g[MAX][MAX], labels[MAX], d[MAX];
queue<int> Q;

void bfs(int s) {
    int v,u;
    labels[s] = 1;
    d[s]=0;
    Q.push(s);
    while (!Q.empty()) {
	u = Q.front(); Q.pop();
	for (v=0; v<n; v++) {
	    if (g[u][v] && labels[v]==0) {
		labels[v] =1;
		d[v] = d[u] +1;
		Q.push(v);
	    }
	}
	labels[u] = 2;
    }
}

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

    for(i=0;i<n;i++){
	scanf("%d %d",&u, &k);
	for(j=0;j<k;j++){
	    scanf("%d",&v);
	    g[u-1][v-1]=1;
	}
    }

    for(i=0; i<n; i++) { labels[i]=0; d[i]=0;}

    bfs(0);

    for(i=0; i<n; i++) printf("%d %d\n", i+1, d[i]);

    return 0;
}

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

//---------------------------------------------------------------
// ------ graph ------ //
using Weight = int;
using Flow = int;
struct Edge {
    int src, dst;
    Weight weight;
    Flow cap;
    Edge() : src(0), dst(0), weight(0) { }
    Edge(int s, int d, Weight w) : src(s), dst(d), weight(w) { }
};
bool operator < (const Edge &e, const Edge &f) {
    return e.weight != f.weight ? e.weight > f.weight : // pqが降順のため
        e.src != f.src ? e.src < f.src : e.dst < f.dst;
}
using Edges = vector<Edge>;
using Graph = vector<Edges>;
using Array = vector<Weight>;
using Matrix = vector<Array>;
void add_edge1(Graph &g, int a, int b, Weight w = 1) {
    g[a].emplace_back(a, b, w);
}
void add_edge2(Graph &g, int a, int b, Weight w = 1) {
    g[a].emplace_back(a, b, w);
    g[b].emplace_back(b, a, w);
}
void add_arc(Graph &g, int a, int b, Weight w = 1) {
    g[a].emplace_back(a, b, w);
}
//---------------------------------------------------------------

vector<int> bfs(int src, Matrix &M) {
    int n = M.size();
    vector<int> dist(n, -1);
    queue<int> Q;
    dist[src] = 0;
    Q.push(src);
    while (!Q.empty()) {
        int cur = Q.front(); Q.pop();
        for (int nxt = 0; nxt < n; nxt++) {
            if (M[cur][nxt] && dist[nxt] < 0) {
                dist[nxt] = dist[cur] + 1;
                Q.push(nxt);
            }
        }
    }
    return dist;
}

int main() {
    int n; cin >> n;
    Matrix M(n, Array(n, 0));
    for (int i = 0; i < n; i++) {
        int u, k; cin >> u >> k;
        while (k--) {
            int v; cin >> v; M[u - 1][v - 1]++;
        }
    }
    vector<int> dist = bfs(0, M);
    for (int i = 0; i < n; i++) {
        cout << i + 1 << " " << dist[i] << endl;
    }
    return 0;
}