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 <bits/stdc++.h>
using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> P;
typedef tuple<int,int,int> tpl;

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define SORT(c) sort((c).begin(),(c).end())
#define REVERSE(c) reverse((c).begin(),(c).end())
#define LB(a,x) lower_bound((a).begin(), (a).end(), x) - (a).begin()
#define UB(a,x) upper_bound((a).begin(), (a).end(), x) - (a).begin()

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RFOR(i,a,b) for(int i=(a)-1;i>=(b);--i)
#define RREP(i,n) RFOR(i,n,0)

#define en "\n"

const double EPS = 1e-9;
const double PI  = acos(-1.0);
const int INT_INF = 2147483647;
const long long LL_INF = 1LL<<60;
const long long MOD = 1000000007;

#define CLR(a) memset((a), 0 ,sizeof(a))

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

struct Node{
    int id, v;
    bool done = false;
    Node(int id, int v=INT_INF): id(id), v(v) {}
    Node(): id(0), v(INT_INF) {}

    bool operator==(const Node& x) { return v == x.v; }
    bool operator!=(const Node& x) { return v != x.v; }
    bool operator<(const Node& x) { return v < x.v; }
    bool operator>(const Node& x) { return v > x.v; }
    bool operator<=(const Node& x) { return v <= x.v; }
    bool operator>=(const Node& x) { return v >= x.v; }

    bool comp(Node node){
        return v < node.v;
    }
};

struct Edge{
    int from, to, cost, id;
    Edge(int from, int to, int cost=1, int id=-1): from(from), to(to), cost(cost), id(id) {}

    bool comp(Edge e){
        return cost < e.cost;
    }
};

struct Graph{
    int N;
    vector<vector<Edge>> adj;
    vector<Node> node;

    Graph(int N): N(N) {
        adj.resize(N, vector<Edge>());
        node.resize(N);
        for(int i=0; i<N; ++i) node[i].id = i;
    }

    Graph() {}

    void add_edge(int i, int j, int cost=1, int id=-1){
        Edge e(i, j, cost, id);
        adj[i].emplace_back(e);
    }

    vector<Edge> get_adj(Node node){
        return adj[node.id];
    }

    void assign(int n){
        N = n;
        adj.assign(N, vector<Edge>());
        node.assign(N, Node());
        for(int i=0; i<N; ++i) node[i].id = i;
    }
};

int main(void){
    int n; cin >> n;
    Graph G(n);

    REP(i,n){
        int u,k; cin >> u >> k;
        u--;
        REP(j,k){
            int v; cin >> v;
            v--;
            G.add_edge(u,v);
        }
    }

    queue<Node> q;
    G.node[0].v = 0;
    q.push(G.node[0]);
    while(q.size()){
        Node nd = q.front(); q.pop();
        if(G.node[nd.id].done) continue;
        G.node[nd.id].done = true;
        G.node[nd.id].v = nd.v;
        for(Edge e : G.adj[nd.id]){
            q.push(Node(e.to, nd.v+1));
        }
    }

    REP(i,n){
        cout << i+1 << " ";
        cout << (G.node[i].v == INT_INF ? -1 : G.node[i].v) << en;
    }
    return 0;
}

C++: //ALDS1_11_C
#include <iostream>
#include <vector>
#define  N     1000
using namespace std;

void BFS(vector<vector<int> > A, vector<int> &d, vector<int> &visit, int v){
	if(v == 0){
		d[0] = 0;
		visit[0] = 1;
	}

	for(int i=0;i<A[v].size();i++){
		if((A[v][i] == 1) && (d[i] > d[v]+1)){
			d[i] = d[v]+1;
			visit[i] = 1;
			BFS(A, d, visit, i);
		}
	}	
}

int main(){
	int n, u, k;
	vector<vector<int> > A;
	vector<int> d, visit;

	cin>>n;
	A.resize(n);
	for(int i=0;i<n;i++){
		A[i].resize(n);
		d.push_back(N);
		visit.push_back(0);
	}

	for(int i=0;i<n;i++)
		for(int j=0;j<n;j++)
			A[i][j] = 0;

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

	BFS(A, d, visit, 0);
	for(int i=0;i<n;i++)
		if(visit[i] == 0)
			d[i] = -1;

	for(int i=0;i<n;i++)
		cout<<i+1<<" "<<d[i]<<endl;

	return 0;
}

C++: #include <iostream>
#include <queue>

using namespace std;

int D[100100] = {-1};//始点からの距離を入れる
int g[1001][1001]={{0}};//要素を0で初期化
void bfs(int src,int n){//srcは開始位置この場合だと頂点1だから0
  // cerr << "bfs_root = " << src << endl;
  queue<int> Q;
  Q.push(src);
  D[src] = 0;
  while (! Q.empty()  ){
    int cur = Q.front();
    Q.pop();
    // cerr << "visiting_" << cur << " " <<D[cur] <<endl;
    for(int dst= 0; dst < n; dst++){
      if(g[cur][dst]==1 && D[dst]==0){
        D[dst]=D[cur]+1;
        Q.push(dst);
      }
    }
  }
}
void ans(int n){
  for (int i = 0; i < n; ++i)
  {
    cout << i+1 <<" "<< D[i]<<endl;
  }

}

int main(){
  // int g[1001][1001]={{0}};//要素を0で初期化
  int n,a,b,c;
  cin >> n;
  for (int i = 0; i < n; ++i)
  {
    cin >> a >> b ;
    for (int i = 0; i < b; ++i)
    {
      cin >> c;
      g[a-1][c-1]=1;/* code */
    }
  }
  bfs(0,n);
  ans(n);
  // for (int i = 0; i < n; ++i)
  // {
  //    for (int j = 0; j < n; ++j)
  //    {
  //     if (j==n-1)
  //     {
  //       cout << g[i][j] << endl;
  //     }else{
  //       cout << g[i][j] <<" ";
  //     }
  //    }
  // }


}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;

ll N;
vector<ll> A;
vector<vector<ll>> G;
vector<bool> used;
vector<ll> dist;

ll gcd(ll a, ll b) { return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) { return b/gcd(a,b)*b;}

void bfs(vector<vector<ll>> &G) {
  queue<ll> que;
  que.push(0);
  used[0] = true;
  dist[0] = 0;

  while(que.size()) {
    ll node = que.front(); que.pop();
    for(auto next_node: G[node]) {
      if (used[next_node]) continue;
      que.push(next_node);
      dist[next_node] = dist[node]+1;
      used[next_node] = true;
    }
  }
}


int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> N;
  G.resize(N);
  used.resize(N, false);
  dist.resize(N, -1);
  rep(i, N) {
    int tmp, k;
    cin >> tmp >> k;
    rep(j, k) {
      int node;
      cin >> node;
      G[tmp-1].push_back(node-1);
    }
  }
  bfs(G);
  rep(i, N) cout << i+1 << " " << dist[i] << endl;
  return 0;
}