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<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

class Graph{
public:
  int v;
  int cost = inf;
  int ftime = -1;
  int ltime = -1;
  vector<int> e;
};
vector<Graph> g;
int cnt = 0;
void dfs(int pos){
  if( g[pos].ftime != -1 ) return;
  cnt++;
  g[pos].ftime = cnt;
  for(int i=0; i<g[pos].e.size(); i++){
    dfs(g[pos].e[i]);
  }
  cnt++;
  g[pos].ltime = cnt;
}
void bfs(int pos){
  queue<int> q;
  q.push(pos);
  while(!q.empty()){
    int p = q.front();
    q.pop();
    for(int i=0; i<g[p].e.size(); i++){
      if( g[ g[p].e[i] ].cost != inf ) continue;
      g[ g[p].e[i] ].cost = min(g[ g[p].e[i] ].cost, g[p].cost + 1);
      q.push(g[p].e[i]);
    }
  }
}

int main(void) {

  int n;
  cin >> n;
  g.resize(n);
  int u, k;
  for(int i=0; i<n; i++){
    cin >> u >> k;
    u--;
    g[u].v = u;
    g[u].e.resize(k);
    for(int j=0; j<k; j++){
      cin >> g[u].e[j];
      g[u].e[j]--;
    }
    sort(g[u].e.begin(), g[u].e.end());
  }

  g[0].cost = 0;
  bfs(0);
  for(int i=0; i<n; i++) cout << g[i].v + 1 << " " << (g[i].cost == inf ? -1 : g[i].cost) << endl;

  // for(int i=0; i<n; i++) dfs(i);
  // for(int i=0; i<n; i++){
  //   cout << g[i].v + 1 << " " << g[i].ftime << " " << g[i].ltime << endl;
  // }



  return 0;
}

// EOF

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 <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++: 4
1 2 2 4
2 1 4
3 0
4 1 3
1 0
2 1
3 2
4 1
Program ended with exit code: 0

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int flag[maxx];
int d[maxx];


void bfs() {
	queue<int>q;

	q.push(1);
	d[1] = 0;
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		for (int i = 1; i <= n; i++) {
			if (m[u][i] == 1 && flag[i] == 0) {
				// ?????°???????????????
				flag[i] = 1;
				// ??´??°??????
				d[i] = d[u] + 1;
				// ?????\??????
				q.push(i);
			}
		}
	}
}
int main()
{

	scanf("%d", &n);
	memset(m, 0, sizeof(m));
	for (int i = 1; i <= n; i++) {
		scanf("%d %d", &u, &num);

		// ????§????
		flag[i] = 0;
		d[i] = -1;
		for (int j = 1; j <= num; j++) {
			scanf("%d", &v);
			m[u][v] = 1;
		}
	}
	bfs();
	for (int i = 1; i <= n; i++) {
		printf("%d %d\n", i, d[i]);
	}
	return 0;
}