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++: //Breadth First Search
#if 0
?????¨?????????30??????
??????????????¨??????????????¢?´¢????????¬????????¨??¢?????´????????????????£?
#endif
#include<iostream>
#include<vector>
#include<queue>
using namespace std;
int n;
int D[100];
int matrix[100][100];
void bfs(int src)
{
    //cerr<<"bfs root = "<<src<<endl;
    queue<int> q;
    q.push(src);
    D[src]=0;
    while(!q.empty())
    {
        int cur=q.front();
        q.pop();
        //cerr<<"visiting "<<cur<<' '<<D[cur]<<endl;
        for(int dst=0;dst<n;dst++)
        {
            if(matrix[cur][dst]==1&&D[dst]==-1)
            {
                D[dst]=D[cur]+1;
                q.push(dst);
            }
        }
    }
};

int main()
{
    vector<int> l[101];
    cin>>n;
    for(int i=0;i<n;i++)
    {
        int u,k;
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            int tmp;
            cin>>tmp;
            l[u].push_back(tmp);
        }
    }
    
    for(int i=0;i<100;i++)
    {
        D[i]=-1;
    }
    
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<n;j++)
        {
            matrix[i][j]=0;
        }
    }
    
    for(int i=1;i<n+1;i++)
    {
        for(int j=0;j<l[i].size();j++)
        {
            matrix[i-1][l[i][j]-1]=1;
        }
    }
    
    bfs(0);
    
    for(int i=0;i<n;i++)
    {
        cout<<(i+1)<<' '<<D[i]<<endl;
    }
}

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

using namespace std;
static const int N = 100;
static const int INFTY = (1<<21); // ?????????????????????(2^21)

int n,M[N][N];
int d[N]; // ?????¢??§?¨??????¶???(color)???????????????

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

int main(){
	int u, k, v;

	cin >> n;
	for(int i=0;i<n;i++){
		 for(int j=0;j<n;j++) M[i][j] = 0;
	}

	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 <queue>
using namespace std;

int n;
int d[101];
bool a[101][101];
const int INF = (1<<21);

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())
    {
        int u = q.front();
        q.pop();
        for(int v=0; v<n; v++)
        {
            if(a[u][v] && d[v] == INF)
            {
                d[v] = d[u] + 1;
                q.push(v);
            }
        }
    }
}


int main() {
    ios::sync_with_stdio(false);
    cin >> n;
    for(int i=0; i<n; i++)
    {
        for(int j=0; j<n; j++)
        {
            a[i][j] = false;
        }
    }

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

    for(int i=0; i<n; i++)
    {
        cout << i+1 << " " << ((d[i] == INF) ? (-1) : d[i]) << endl;
    }
    return 0;
}

C++: #include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>
#include <queue>

using namespace std;
static const int N=100;
static const int INFTY=(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]=INFTY;
    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]!=INFTY) continue;
            d[v]=d[u]+1;
            q.push(v);
        }
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<((d[i]==INFTY)?(-1):d[i])<<endl;
    }
}

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

    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;
}