Go: package main

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

type Queue []int

func (q *Queue) push(v int) {
	*q = append(*q, v)
}

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	nVerts := scanInt(sc)
	graph := make([][]int, nVerts+1)

	for i := 0; i < nVerts; i++ {
		u := scanInt(sc)
		nDegrees := scanInt(sc)

		graph[u] = make([]int, nDegrees)
		for d := 0; d < nDegrees; d++ {
			graph[u][d] = scanInt(sc)
		}
	}

	paths := make([]int, nVerts+1)

	queue := Queue(make([]int, 0))
	queue.push(1)
	paths[1] = 1

	for len(queue) > 0 {
		u := queue.pop()
		d := paths[u] + 1
		for _, v := range graph[u] {
			if paths[v] == 0 {
				paths[v] = d
				queue.push(v)
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= nVerts; i++ {
		fmt.Fprintf(w, "%d %d\n", i, paths[i]-1)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

C++: // -*- mode:c++; coding:utf-8; c-basic-offset:2; -*-
// ALDS1_11_C: Breadth First Search

#include <algorithm>
#include <cstdio>
#include <queue>

using uint = unsigned int;

class Graph {
  const uint n_;
  uint* const g_;
  int* const depth_;
  
public:
  Graph(uint n) : n_(n),
                  g_(new uint[(n_*n_)]),
                  depth_(new int[n])
  {
    std::fill(g_, g_+(n_*n_), 0u);
  }

  ~Graph()
  {
    delete[] g_;
    delete[] depth_;
  }
  
  uint* operator [](uint i) const { return g_+(n_*i); }

  int* depth() const { return depth_; }

  void bfs()
  {
    init_depth();
    std::queue<uint> q;
    auto i = 0u;
    q.push(i);
    depth_[i] = 0;
    while (!q.empty()) {
      i = q.front();
      for (auto j = 0u; j < n_; ++j) {
        if ((*this)[i][j] && depth_[j] == -1) {
          q.push(j);
          depth_[j] = depth_[i]+1;
        }
      }
      q.pop();
    }
  }

private:
  void init_depth()
  {
    std::fill(depth_, depth_+(n_), -1);
  }
};

int main()
{
  uint n;
  std::scanf("%u", &n);

  Graph g(n);

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

  g.bfs();
  auto depth = g.depth();
  for (auto i = 0u; i < n; ++i) {
    std::printf("%u %d\n", i+1, depth[i]);
  }
}

// eof

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

using namespace std;

static const int N = 100;

int n,d[N],M[N][N];//d[]...?§??????????????????¢(-1?????°?????????)???M[][]?????£??\???????????§????????????

void dfs(int r) {
	queue<int> q;//queue??§?????????
	q.push(r);//?§?????????£??\
	for (int i = 0; i < n; i++) d[i] = -1;//??????????????????
	d[r] = 0;//?§????????????¢???0

	int u;
	while (!q.empty()) {//??¢?´¢???????????§??°?????????
		u = q.front();//u????????\?????????????????¢?´¢???????????£?????????????????£??\
		q.pop();//?????\???????????????????´????????????????

		for (int v = 0; v < n; v++) {//??£??\????????????????????????
			if (M[u][v] == 0) continue;//?§??????¨??????????????§?????°?????????????????´???????????????
			if (d[v] != -1) continue;//?§??????¨????????¢???????????£??????????????¢?´¢???????????£??????????????´??????????????????
			d[v] = d[u] + 1;//??????u????§??????¨??£??\?????????????????????????????¢1???1?????????????????????????????????+1???
			q.push(v);//?????\??????v?????????
		}
	}
	for (int i = 0; i < n; i++) {
		cout<<i+1<<" "<<d[i]<<endl;//??????
	}
}

int main() {
	int u, p, v;
	cin >> n;
	for (int i = 0; i < n; i++) {//?????????(d[]?????¢????????????dfs??§?±??????????????????§????????????????????????)
		for (int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}

	for (int i = 0; i < n; i++) {//??????????????????
		cin >> u >> p;
		u--;//0?????????????????????
		for (int j = 0; j < p; j++) {
			cin >> v;
			v--;//0?????????????????????
			M[u][v] = 1;
		}
	}

	dfs(0);//??????0????§??????¨??????

	return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <cstdio>
#include <utility>
#include <string>
#include <cmath>
#include <cstdlib>
#include <cstring>

using namespace std;

typedef uint64_t u64;
typedef int64_t s64;
typedef uint32_t u32;
typedef int32_t s32;
typedef vector<s32> vs32;
typedef vector<u32> vu32;
typedef vector<s64> vs64;
typedef vector<u64> vu64;

const double PI=3.14159265358979323846;

#define MAX(x, y) ((x) < (y) ? (y) : (x))
#define MIN(x, y) ((x) > (y) ? (y) : (x))

#define rep(i, N) for(int i = 0; i < N; ++i)

#define CEIL(x, y) (((x) + (y) - 1) / (y))
#define MOD 1000000007ULL

class DirectedGraph
{
public:
    DirectedGraph() {}
    DirectedGraph(int n)
    : g(vector< vs32 >(n)), dist(vs32(n, -1))
    {}
    ~DirectedGraph() {}

    void bfs(int u)
    {
        int d = 0;
        dist[u]  = 0;
        queue<int> q;
        q.push(u);
        while (!q.empty())
        {
            int n = q.size();
            ++d;
            rep (i, n)
            {
                int v = q.front();
                q.pop();
                rep (j, g[v].size())
                {
                    if (dist[g[v][j]] < 0)
                    {
                        dist[g[v][j]] = d;
                        q.push(g[v][j]);
                    }
                }
            }
        }
    }

    vector< vs32 > g;
    vs32 dist;
};

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

    int n;
    cin >> n;

    DirectedGraph dg(n);
    int u, v;
    int c;
    rep (i, n)
    {
        cin >> u >> c;
        --u;
        dg.g[u].resize(c);
        rep (j, c)
        {
            cin >> v;
            --v;
            dg.g[u][j] = v;
        }
    }

    dg.bfs(0);

    rep (i, n)
    {
        cout << i + 1 << " " << dg.dist[i] << "\n";
    }
    return 0;
}

C++: #include <cstdio>
#include <queue>
using namespace std;
#define MAX_N 100

int g[MAX_N+1][MAX_N+1];
int d[MAX_N+1];
bool visited[MAX_N+1];
queue<int> que;

int n;
int t = 1;

void bfs(int id) {
  visited[id] = true;
  que.push(id);
  while(!que.empty()) {
    int v = que.front(); que.pop();
    queue<int> next_que;
    for(int u=1;u<=n;u++) {
      if(g[v][u]!=0 && !visited[u]) {
        visited[u]=true;
        next_que.push(u);
        d[u] = t;
      }
    }
    if(que.empty()){
      que = next_que;
      t++;
    }
  }
}

int main() {
  scanf("%d\n",&n);
  int u,k,v;
  for(int i=0;i<n;i++) {
    scanf("%d %d ",&u,&k);
    for(int j=0;j<k;j++) {
      scanf("%d ",&v);
      g[u][v] = 1;
    }
  }
  bfs(1);
  for(int i=1;i<=n;i++) {
    if(visited[i])
      printf("%d %d\n",i,d[i]);
    else
      printf("%d -1\n",i);
  }
}

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

void BFS(int s, const vector<vector<int> >& G, vector<int>& D){
    queue<int> Q;
    Q.push(s);
    D[s] = 0;
    while (!Q.empty()) {
        int f = Q.front();
        for (int i = 0; i < G[f].size(); i++) {
            if (D[G[f][i]] == -1) {
                D[G[f][i]] = D[f] + 1;
                Q.push(G[f][i]);
            }
        }
        Q.pop();
    }
}

int main(){
    int n;
    cin >> n;
    vector<vector<int> > G(n + 1);
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            G[u].push_back(v);
        }
    }
    vector<int> D(n + 1, -1);
    BFS(1, G, D);
    for (int i = 1; i <= n; i++) {
        cout << i << " " << D[i] << endl;
    }
    return 0;
}