Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Scan()
	num, _ := strconv.Atoi(sc.Text())
	nodes := make(map[int]*node)

	for i := 0; i < num; i++ {
		sc.Scan()
		id, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		nodeNum, _ := strconv.Atoi(sc.Text())
		n := node{id, make([]int, 0), -1}
		for j := 0; j < nodeNum; j++ {
			sc.Scan()
			nid, _ := strconv.Atoi(sc.Text())
			n.nexts = append(n.nexts, nid)
		}
		nodes[id] = &n
	}
	nodes[1].depth = 0

	walk(1, 0, &nodes)
	for i := 1; i < len(nodes)+1; i++ {
		fmt.Printf("%v %v\n", (*nodes[i]).id, (*nodes[i]).depth)
	}
}

var time int
var record [100][100]bool
var q Queue

func walk(nid int, from int, nodes *map[int]*node) {
	q.Enqueue((*nodes)[nid])
	for !q.IsEmpty() {
		n := q.Dequeue().(*node)
		for _, v := range n.nexts {
			n2 := (*nodes)[v]
			if n2.depth != -1 {
				continue
			}
			n2.depth = n.depth + 1
			q.Enqueue((*nodes)[v])
		}
	}
}

type node struct {
	id    int
	nexts []int
	depth int
}

// Queue is Queue
type Queue struct {
	val []interface{}
}

// Enqueue value
func (queue *Queue) Enqueue(val interface{}) {
	queue.val = append(queue.val, val)
}

// Dequeue value
func (queue *Queue) Dequeue() interface{} {
	res := queue.val[0]
	queue.val = queue.val[1:len(queue.val)]
	return res
}

// IsEmpty return true when queue is empty
func (queue *Queue) IsEmpty() bool {
	return len(queue.val) == 0
}

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

using namespace std;
static const int INF = 1e9;
static const int SIZE = 101;
typedef pair<int, int> P;

int d[SIZE];
vector<int> G[SIZE];

void solve()
{
	int n;
	cin >> n;
	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);
		}
	}
	for (int i = 0; i < SIZE; ++i)
	{
		d[i] = INF;
	}
	d[1] = 0;
	queue<P> que;
	que.push(P(0, 1));
	while (!que.empty())
	{
		P p = que.front();
		que.pop();
		int v = p.second;
		for (int i = 0; i < G[v].size(); ++i)
		{
			int to = G[v][i];
			if (d[to] > p.first + 1)
			{
				d[to] = p.first + 1;
				que.push(P(d[to], to));
			}
		}
	}
	for (int i = 1; i <= n; ++i)
	{
		if (d[i] == INF)
		{
			cout << i << " " << -1 << endl;
		}
		else
		{
			cout << i << " " << d[i] << endl;
		}
	}
}

int main()
{
	solve();
	return(0);
}

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

int main(){
  int n;
  cin >> n;
  
  vector<vector<int>> g(n,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;
      v--;
      g[i].push_back(v);
      // g[v].push_back(i);
    }
  }

  vector<int> dist(n,-1);
  dist[0] = 0;
  queue<int> q;
  q.push(0);
  while(!q.empty()){
    int node = q.front();
    q.pop();
    for(int next:g[node]){
      if(dist[next]!=-1) continue;
      dist[next] = dist[node]+1;
      q.push(next);
    }
  }
  for (int i = 0; i < n; i++)
  {
    cout << i+1 << " " << dist[i] << endl;
  }  
}

C++: #include <algorithm>
#include <iostream>
#include <list>
#include <vector>

class TNode
{
	std::list<TNode*> FNexts;
	int  FDistance;
	bool FVisited;
public:
	TNode(int Index)
	: FDistance(-1), FVisited(false)
	{
	}
	
	int GetDistance()const {return FDistance;}
	
	void Push(TNode* New)
	{
		FNexts.push_back(New);
	}
	
	void Visit(int Distance)
	{
		if(FVisited) return;
		FDistance = Distance;
		FVisited  = true;
		for(std::list<TNode*>::iterator It = FNexts.begin(); It != FNexts.end(); ++It){
			(*It)->Visit(Distance + 1);
		}
	}
};

class TGraph
{
	std::vector<TNode*> FNodes;
	std::vector<int> FDistances;
public:
	TGraph(int Count)
	: FNodes(Count + 1), FDistances(Count + 1, -1)
	{
		for(int i = 1; i < Count + 1; ++i){
			FNodes[i] = new TNode(i);
		}
	}
	
	~TGraph()
	{
		for(unsigned int i = 1; i < FNodes.size(); ++i){
			delete FNodes[i];
		}
	}
	
	void InputNode()
	{
		int Index;
		std::cin >> Index;
		int BranchCount;
		std::cin >> BranchCount;
		for(int i = 0; i < BranchCount; ++i){
			int Target;
			std::cin >> Target;
			FNodes[Index]->Push(FNodes[Target]);
		}
	}
	
	void BreathFirstSearch()
	{
		FNodes[1]->Visit(0);
	}
	
	int Distance(int Target)const
	{
		return FNodes[Target]->GetDistance();
	}
};

int main()
{
	int Count;
	std::cin >> Count;
	TGraph Graph(Count);
	for(int i = 0; i < Count; ++i){
		Graph.InputNode();
	}
	Graph.BreathFirstSearch();
	
	for(int i = 0; i < Count; ++i){
		std::cout << i + 1 << " " << Graph.Distance(i + 1) << std::endl;
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#define rep(i, n) for(int i = 0; i < (int)(n); ++i)
#define REP(i, n) for(int i = 1; i < (int)(n); ++i)
using namespace std;

int n;
vector<vector<int>> graph(100);
queue<int> q;
vector<int> dist(100, -1);

void BFS() {
    int u = q.front();
    q.pop();
    for (int v : graph[u]) {
        if (dist[v] == -1) {
            dist[v] = dist[u] + 1;
            q.push(v);
        }
    }
    return;
}

int main() {
    cin >> n;
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        rep(i, k) {
            int v;
            cin >> v;
            graph[u - 1].push_back(v - 1);
        }
    }
    
    q.push(0);
    dist[0] = 0;
    while (q.size() > 0) BFS();
    rep(i, n) cout << i + 1 << " " << dist[i] << endl;
    return 0;
}