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 pair<int,int> P;
typedef long long ll;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0;}
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0;}

int n;
vector<vector<int> >g;
int dist[110];
void bfs(int u) {
    queue<int> q;
    q.push(u);
    rep(i,n) dist[i] = -1;
    dist[u] = 0;
    while(!q.empty()) {
        int v = q.front();q.pop();
        for(int i = 0;i<g[v].size();i++) {
            int nv = g[v][i];
            if(dist[nv] == -1) {
                q.push(nv);
                dist[nv] = dist[v] + 1;
            }               
        }
    }
}
int main() {
    cin >> n;
    g.assign(n,vector<int>());
    rep(i,n) {
        int u,k;
        cin >> u >> k;
        u--;
        rep(j,k) {
            int v;
            cin >> v;
            v--;
            g[u].push_back(v);
        }
    }
    bfs(0);
    rep(i,n) cout << i+1 << " " << dist[i] << endl;
}

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

using namespace std;

struct Node{
  int p[100]={0}, d=-1, c[100], c_n;
};

Node nodes[101];

void search(int x){
    for(int i=0;i<nodes[x].c_n;++i){
        if(nodes[nodes[x].c[i]].d > nodes[x].d + 1 || nodes[nodes[x].c[i]].d == -1){
            nodes[nodes[x].c[i]].d = nodes[x].d + 1;
        }
    }
    
    for(int i=0;i<nodes[x].c_n;++i){
        if(nodes[nodes[x].c[i]].d == nodes[x].d + 1){
            search(nodes[x].c[i]);
        }
    }
    return;
}

int main(){
    int n, num, child;
    cin >> n;
    
    
    
    for(int i=1;i<=n;++i){
        cin >> num;
        
        if(num == 1){
            nodes[num].d=0;
        }
        
        cin >> nodes[num].c_n;
        for(int j=0;j<nodes[num].c_n;++j){
            cin >> nodes[num].c[j];
        }
    }
    
    search(1);
    
    for(int i=1;i<=n;++i){
        cout << i << " " << nodes[i].d << endl;
    }
    
    
    return 0;
}

C++: // http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_B

#include <iostream>
#include <iomanip>

#include <vector>
#include <string>
#include <iterator>
#include <algorithm>
#include <queue>

typedef long long ll;
const long double PI = (acos(-1));
const long long MOD = 1000000007;
#define rep(i,n) REP(i,0,n)
#define REP(i,x,n) for(int i=x;i<n;++i)

using namespace std;

// change min/max
template<class T> inline bool chMin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chMax(T& a, T b) { if (a < b) { a = b; return true; } return false; }

template<class T> void output(std::vector<T> & A) {
    const int n = A.size();
    for (int i = 0; i < n - 1; ++i) {
        std::cout << A[i] << " ";
    }
    std::cout << A[n - 1] << std::endl;
}

const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
vector<vector<int>> M;
vector<int> colour, d;
int tt = 0;
queue<int> que;

void bfs(int u) {
    que.push(u);
    colour[u] = GRAY;

    while (!que.empty()) {
        const int v = que.front(); que.pop();
        for (int s : M[v]) {
            if (colour[s] == WHITE) {
                que.push(s);
                d[s] = d[v] + 1;
                colour[s] = GRAY;
            }
        }
        colour[v] = BLACK;
    }
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout << std::fixed << std::setprecision(15);

    // populate M
    int n; cin >> n;
    M = vector<vector<int>>(n);
    colour = vector<int>(n, 0);
    d = vector<int>(n, -1);

    rep(i, n) {
        int from; cin >> from; --from;
        int m; cin >> m;
        rep(j, m) {
            int to; cin >> to; --to;
            M[from].push_back(to);
            // M[to].push_back(from);
        }
    }

    // bfs
    d[0] = 0;
    bfs(0);

    rep(i, n) {
        cout << (i + 1) << " " << d[i] << endl;
    }

    return 0;
}

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

using namespace std;

int n;
int u[10010], k[10010],  v[10010][10010];
int answer[10010][10010];

int D[10010];
void bfs(int src){
	//cerr << "bfs root = " << src << endl;
	queue<int> Q;
	Q.push(src);
	D[src] = 0;
	//int cnt = 0;
	while(! Q.empty()){
		int cur = Q.front();
		Q.pop();
		//cerr << "visiting " << cur << " " << D[cur] << endl;
		
		for(int dst = 0; dst < 1001; ++dst){
			if(answer[cur - 1][dst - 1] == 1 && D[dst] > 10000){
				D[dst] = D[cur] + 1; 
				Q.push(dst);
			}
		}

	}
	for(int i = 1; i  < n + 1; ++i ){
		if(D[i] < 10000){
			cout << i << " " <<  D[i] << endl;
		}else{
			cout << i << " " << -1 << endl;
		}
	}

	
}

int main(){
	cin >> n;
	for(int i = 0; i < 1001; ++i){
		for(int j = 0; j < 1001; ++j)
			answer[i][j] = 0;
	}
	for(int i = 0; i < 10010; ++i){
		D[i] = 10010;
	}

	
	
	for(int i = 0; i < n; ++i){
		cin >> u[i] >> k[i];
		for(int j = 0; j < k[i]; ++j){
			cin >> v[i][j];
			answer[u[i] - 1][v[i][j] - 1] = 1;
		} 
	}
	for(int i = 0; i < n; ++i){
		for(int j = 0; j < n; ++j){
			//cout << answer[i][j] << " ";
		} 
		//cout << endl;
	}
	bfs(1);
}