Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, &g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

func fillDistancesByBreadthFirstSearch(g *DirectedGraph, startNode *DirectedGraphNode) {
	startNode.visited = true
	startNode.d = 0

	queue := Queue{}
	queue.enqueue(startNode)
	for !queue.isEmpty() {
		u := queue.dequeue().node
		for _, adjacent := range u.adjacents {
			if !adjacent.visited {
				adjacent.visited = true
				adjacent.d = u.d + 1
				adjacent.parent = u
				queue.enqueue(adjacent)
			}
		}
		u.visited = true
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	// fmt.Println(g)
	fillDistancesByBreadthFirstSearch(g, &g.nodes[1])
	// fmt.Println(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		distance := node.d
		if distance == infty {
			distance = -1
		}
		fmt.Println(node.key, distance)
	}
}

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

int M[200][200];
string color[200];
queue<int> q;
int d[200];
int n;
const int INF = 1001001001;

void bfs(int s){
    rep(i, n){
        color[i] = "WHITE";
        d[i] = -1;
    }

    color[s] = "GRAY";
    d[s] = 0;
    q.push(s);
    while(!q.empty()){
        int u = q.front(); q.pop();
        for (int i = 0; i <= n; i++){
            if(M[u][i] && color[i] == "WHITE"){
                color[i] = "GRAY";
                d[i] = d[u] + 1;
                q.push(i);
            }
        }
        color[u] = "BLACK";
    }
}

int main() {
    cin >> n;
    rep(i, n){
        int a, b; cin >> a >> b;
        rep(j, b){
            int x; cin >> x;
            x--;
            M[i][x] = 1;
        }
    }
    bfs(0);
    rep(i, n){
        cout << i+1 << " " << d[i] << endl;
    }

    return 0;
}

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

using namespace std;
using Graph=vector<vector<int>>;

void breadth_firstsearch(Graph &graph,int vertex,queue<int> qdata,vector<int> &distance){
  distance.at(vertex)=0;
  qdata.push(vertex);
  while(!qdata.empty()){
    int ver=qdata.front();
    qdata.pop();
    for(int v : graph.at(ver)){
      if(distance.at(v)!=-1) continue;
      distance.at(v)=distance.at(ver)+1;
      qdata.push(v);
    }
  }
}


int main(void) {
	int size, vnum, adjnum, temp;
	cin >> size;
	Graph graph(size);
	queue<int> qdata;
	vector<int> distance(size,-1);

	for (int i = 0; i < size; i++) {
		cin >> vnum >> adjnum;
		for (int j = 0; j < adjnum; j++) {
			cin >> temp;
			graph.at(vnum - 1).push_back(temp - 1);
		}
	}
  breadth_firstsearch(graph,0,qdata,distance);

	for (int i = 0; i < size; i++) {
		cout << i + 1 << " " <<distance.at(i)<< endl;
	}
	return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
#define rep(i, n) for(int i=0;i<(n);i++)
const int INF = 1001001001;
int n, u, k;
int D[100];
vector<int> edges[100];
void bfs(int src) {
	
	
	queue<int> Q;	
	Q.push(src);
	D[src] = 0;//D[*]が始点から点*への距離
	while (!Q.empty()) {
		int cur = Q.front();//curは今取り扱ってる点
		Q.pop();
		
		for (int dst = 0; dst < n; dst++) {//dstはcurから移動可能な点
			vector<int>::iterator result = find(edges[cur].begin(), edges[cur].end(), dst);
			if (result != edges[cur].end() && D[dst] == INF) {
				D[dst] = D[cur] + 1;
				Q.push(dst);
			}
		}
	}
}

int main() {
	cin >> n; //n頂点
	

	for (int i = 0; i < n; i++)//iは頂点
	{
		cin >> u >> k;
		for (int j = 0; j < k; j++)
		{
			int l;
			cin >> l;
			edges[u - 1].push_back(l-1);
		}//入力終わり
		D[i] = INF;
	}
		bfs(0);
	for (int i = 0; i < n; i++) {
		if (D[i] != INF)cout << i + 1 << " " << D[i] << endl;
		else cout << i + 1 << " " << -1 << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<tuple>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<deque>
#include<cmath>
#include<stack>
#define rep(i,n) for(int i = 0;i<n;i++)
#define _GLIBCXX_DEBUG
using ll = long long; 
using namespace std;

static const int N = 100;
static const int INF = (1<<21);

int n,M[N][N];
int d[N];

void bfs(int s) {
    queue<int>q;
    q.push(s);
    for(int i = 0; i< n;i++) d[i] = INF;
    d[s] = 0;
    int u;
    while(!q.empty()) {
        u = q.front();q.pop();
        for(int v = 0;v < n;v++) {
            if(M[u][v] == 0) continue;
            if(d[v] != INF) continue;
            d[v] = d[u]+1;
            q.push(v);
        }
    }
    for(int i = 0;i < n; i++) {
        cout << i+1 << " " << ( (d[i] == INF) ? (-1):d[i]) << endl;
    }}

    int main() {
        int u,k,v;
        rep(i,n) {
            rep(j,n) {
                M[i][j] = 0;
            }
        }
        cin >> n;
        for(int i = 0;i < n;i++) {
            cin >> u >> k;
            u--;
            for(int j = 0;j<k;j++) {
                cin >> v;
                v--;
                M[u][v] = 1;
            }
        }
        bfs(0);
        return 0;
    }

C++: #include<iostream>
#include<vector>
#include<queue>
#define WHITE 0 //未発見
#define GRAY 1 //発見
#define BLACK 2 //探索済み
#define NIL -1
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
typedef vector< vector<int> > table;

void bfs(table& m,int s)
{
    vector<int> color(m.size(),WHITE);
    vector<int> dist(m.size(),NIL);
    queue<int> q;
    q.push(s);
    color[s]=GRAY;
    dist[s]=0;

    while (!q.empty())
    {
        int u=q.front();q.pop();
        rep(v,m.size())
        {
            if(dist[v]!=NIL)continue;
            if(m[u][v]==1 && color[v]==WHITE)
            {
                dist[v]=dist[u]+1;
                color[v]=GRAY;
                q.push(v);
            }
        }
        color[u]=BLACK;
    }
    
    rep(i,m.size()) cout<<i+1<<" "<<dist[i]<<endl;
}

int main()
{
    int n;
    cin>>n;
    table m(n,vector<int>(n,0));
    rep(i,n)
    {
        int u,k;
        cin>>u>>k;
        rep(j,k)
        {
            int v;
            cin>>v;
            m[u-1][v-1]=1;
        }
    }

    bfs(m,0);

    return 0;
}