Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

C++: #include <bits/stdc++.h>
//#define int long long
#define double long double
#define rep(i, a, n) for(int i = (int)(a);(i) < (int)(n);++(i))
#define repe(i, a, n) for(int i = (int)(a);(i) <= (int)(n);++(i))
#define repif(i, a, x) for(int i = (int)(a);(x);++(i))
#define repr(i, a, n) for(int i = ((int)(a)-1);(i) >= (int)(n);--(i))
#define reper(i, a, n) for(int i = (int)(a);(i) >= (int)(n);--(i))
#define SZ(x) ((int)(x).size())
#define ALL(x) begin(x), end(x)
#define CEIL(x) ((int)ceil(((double)x)))
#define POW(x, y) ((int)pow(x, y))
#define UNIQUE(x) (x).erase(unique(ALL((x))), end(x))
#define gcd(x, y) __gcd(x, y)
#define lcm(x, y) ((x)/gcd(x,y)*(y))
#define isin(x, l, r) ((l) <= (x) and (x) < (r))
#define fcout(n) cout << fixed << setprecision(n)
#define rcout(n) cout << right << setw(n)
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define PI (acosl(-1))
#define EPS (1e-10)
#define INF LLONG_MAX
#define INF32 INT32_MAX
#define MOD 1000000007LL
using namespace std;
using VI = vector<int>;
using PII = pair<int, int>;
using TIII = tuple<int, int, int>;
using VPII = vector<PII>;
using VTIII = vector<TIII>;
using Complex = complex<double>;
template<typename T, template<typename> typename C = less> using PQ = priority_queue<T, vector<T>, C<T>>;
template<typename T> inline bool chmax(T& a, const T& b, bool t = false){ if(a<b or (t and a == b)){ a=b; return true; } return false; }
template<typename T> inline bool chmin(T& a, const T& b, bool t = false){ if(a>b or (t and a == b)){ a=b; return true; } return false; }


int n;
VI g[110];
int d[110];


signed main(){
    cin >> n;
    rep(i, 0, n){
        int u, k;
        cin >> u >> k;
        u--;
        int v;
        rep(j, 0, k){
            cin >> v;
            g[u].pb(v-1);
        }
    }

    fill(d, d+n, -1);
    queue<int> q;
    d[0] = 0;
    q.push(0);
    while(!q.empty()){
        int p = q.front(); q.pop();
        rep(i, 0, SZ(g[p])) if(d[g[p][i]] == -1) d[g[p][i]] = d[p]+1, q.push(g[p][i]);
    }

    rep(i, 0, n) cout << i+1 << ' ' << d[i] << endl;

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
typedef vector <int> vi;
typedef vector <vi> vvi;

int addedge(vvi &graph, int y, int x, int val=1){
	graph[y][x] = val;
	return val;
}

int make_graph(vvi &graph, vi &stamp){
	int n1=graph.size(), n2, row, col;

	for (int j=0; j<n1; j++){
		cin>>row;
		cin>>n2;
		for (int i=0; i<n2; i++){
			cin>>col;
			addedge(graph, row-1, col-1);
		}
		stamp[j] = -1;
	}
	return 0;
}

int Breadth_First_Search(vvi &graph, vi &stamp){

	queue <int>qu;
	qu.push(0);
	stamp[0] = 0;
	while (! qu.empty()){
		int tmp = qu.front();
		qu.pop();
		for (int i=0; i<(int)graph[0].size(); i++){
			if (graph[tmp][i]==1 && stamp[i]==-1){
				stamp[i] = stamp[tmp]+1;
				qu.push(i);
			}
		}
	}
	return 0;
}

int resultout(vi &stamp){
	for (int i=0; i<int(stamp.size()); i++){
		cout<<i+1<<" "<<stamp[i]<<endl;
	}
	return 0;
}

int main(void){

	int n, row;
	cin>>n;
	vvi G(n, vi(n));
	vi stamp(n);

	make_graph(G, stamp);

	Breadth_First_Search(G, stamp);

	resultout(stamp);

	return 0;
}

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

#define REP(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define all(x) (x).begin(),(x).end()
using ll = long long;
string char_to_string(char val) {
  return string(1, val);
}
int char_to_int(char val) {
  return val - '0';
}
template<class T> inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template<class T> inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
int vector_finder(std::vector<ll> vec, int number) {
  auto itr = std::find(vec.begin(), vec.end(), number);
  size_t index = std::distance( vec.begin(), itr );
  if (index != vec.size()) { // 発見できたとき
    return 1;
  }
  else { // 発見できなかったとき
    return 0;
  }
}

int main() {
  int n; cin >> n;
  vector<int> u(n), k(n); 
  vector<vector<int>> v(n);
  REP(i, n) {
    cin >> u[i] >> k[i];
    REP(m, k[i]) {
      int p; cin >> p;
      v[i].push_back(p);
    }
  }

  vector<int> ans; ans.assign(n + 1, -1);
  queue<int> Q;
  Q.push(1); ans[Q.front()] = 0;
  while(!Q.empty()) {
    int i = Q.front();
    Q.pop();
    for(int m = 0; m < k[i - 1]; ++m) {
      if(ans[v[i - 1][m]] == -1) {
        Q.push(v[i - 1][m]);
        ans[v[i - 1][m]] = ans[i] + 1;
      }
    }
  }
  for(int i = 1; i < n + 1; ++i) {
    cout << i << " " << ans[i] << endl;
  }
}

C++: #include <iostream>
#include <string>
#include <unordered_map>
#include <stdio.h>
#include <list>
#include <vector>
#include <algorithm>
#include <stack>
#include <queue>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; ++i)
typedef long long ll;

int main()
{
	int n; cin >> n;
	vector <vector<int>> v(n);
	rep(i,n)
	{
		int hoge;
		cin >> hoge;
		int k;
		cin >> k;
		rep(j,k)
		{
			int foo;
			cin >> foo;
			v[i].push_back(foo-1);
		}
	} 
	vector<int> color(n);
	rep(i,n)color[i]=0;
	queue<int> Q;
	vector <int> d(n);
	rep(i,n)d[i]=-1;

	color[0] = 1;
	d[0]=0;
	Q.push(0);
	while(!Q.empty())
	{
		int u = Q.front();
		Q.pop();
		rep(i,v[u].size())
		{
			if(color[v[u][i]]==0)
			{
				color[v[u][i]]=1;
				d[v[u][i]]=d[u]+1;
				Q.push(v[u][i]);
			}
		}
	}

	rep(i,n)cout<<i+1<<' '<<d[i]<<endl;
	return 0;
}