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 INF 0x3f3f3f3f
#define rep(i,n)for(int i=0;i<n;i++)
using namespace std;
typedef pair<int,int>P;

vector<int>E[100];
int d[100];
int main(){
	int n;cin>>n;
	rep(i,n){
		int u,k;cin>>u>>k;u--;
		rep(i,k){
			int v;cin>>v;v--;
			E[u].push_back(v);
		}
	}
	memset(d,0x3f,sizeof(d));
	queue<P>que;
	d[0]=0;que.push(P(0,0));
	while(!que.empty()){
		P p=que.front();que.pop();
		for(int u:E[p.second]){
			if(d[u]>p.first+1){
				d[u]=p.first+1;
				que.push(P(d[u],u));
			}
		}
	}
	rep(i,n){
		if(d[i]==INF)cout<<i+1<<" -1"<<endl;
		else cout<<i+1<<' '<<d[i]<<endl;
	}
}

C++: // 幅優先探索
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>

#include<queue>

using namespace std;

#define MAX_N 100
// 値の定義
const int INV = -1;
const int EXIST = 1;
const int NO_EXIST = 0;

const int YES = 0;
const int NO = -1;

// グラフ情報を保持する配列
int ary_graph[MAX_N + 1][MAX_N + 1];

// 頂点１からの距離を保持する配列
int vertex_distance[MAX_N + 1];
// 頂点１からの訪問状態を保持する配列
int ary_visit[MAX_N + 1];

int n = 0;
int nt[MAX_N + 1];

void widthFirstSearch(int start_vertex);

int main(void)
{
    int u, num, v_num, start_point;

    for(int i = 0; i < MAX_N + 1; i++)
    {
    	vertex_distance[i] = 0;
        ary_visit[i] = NO;

        for(int j = 0; j < MAX_N + 1; j++)
        {
            // 配列の初期化
            ary_graph[i][j] = NO_EXIST;
        }
    }

    cin >> n;

    for(int i = 0; i < n; i++)
    {
        cin >> u >> num;

        // 0オリジンにする
        u--;

        for(int j = 0; j < num; j++)
        {
            // 隣接点を記憶する
            cin >> v_num;

            // 0オリジンにする
            v_num--;
            ary_graph[u][v_num] = EXIST;
        }
    }

    for(int i = 0; i < n; i++)
    {
        if( ary_visit[i] == NO )
        {
            start_point = i;

            // 幅優先探索を実施
            widthFirstSearch(i);
        }
    }

    // 結果の表示
    for(int i = 0; i < n; i++)
    {
        if( i != start_point && vertex_distance[i] == 0 )
        {
            // 開始点から到達不可能な点だった
            vertex_distance[i] = INV;
        }

        printf("%d %d\n", i + 1, vertex_distance[i]);
    }

    return 0;
}

// u に隣接する v を番号順に取得
int next(int u)
{
    int ret = INV;

    for(int v = nt[u]; v < n; v++)
    {
        nt[u] = v + 1;

        if( ary_graph[u][v] == EXIST )
        {
            // 隣接点が存在する
            ret = v;
            break;
        }
    }

    return ret;
}

// 幅優先探索を実施する関数
// start_vertex : 起点となる頂点のNo.
// vertex_num : グラフの頂点数
void widthFirstSearch(int start_vertex)
{

    queue<int> Q;

    Q.push(start_vertex);
    vertex_distance[start_vertex] = 0;
    ary_visit[start_vertex] = YES;

    while( !Q.empty() )
    {
        int u = Q.front();

        for(int i = 0; i < n; i++)
        {
            // 隣接点を全て検索する
            int v = next(u);

            if( v == INV )
            {
                // 隣接点が無くなったらキューから削除して, 処理終了
                Q.pop();
                break;
            }

            if( ary_visit[v] == NO
                && ary_graph[u][v] == EXIST )
            {
                // 訪問済み
                ary_visit[v] = YES;

                Q.push(v);
                vertex_distance[v] = vertex_distance[u] + 1;
            }
        }
    }

    return;
}

C++: #include <iostream>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <algorithm>
#include <cmath>
#include <string>
using namespace std;
typedef long long lli;
typedef vector<lli> vll;
typedef vector<bool> vbl;
typedef vector<vector<lli> > mat;
typedef vector<vector<bool> > matb;
typedef vector<string> vst;
typedef pair<lli,lli> pll;
typedef pair<double,double> pdd;

lli n;
mat g;

lli u,k,v;

queue<lli> q;
queue<lli> d;
vbl vis;
vll ans;


int main(){
    cin >> n;
    g = mat(n+1);
    vis = vbl(n+1);
    ans = vll(n+1);
    for(lli i = 0;i < n;i++){
        cin >> u >> k;
        for(lli j = 0;j < k;j++){
            cin >> v;
            g[u].push_back(v);
        }
    }
    q.push(1);
    d.push(0);
    while(!q.empty()){
        lli p = q.front();
        lli r = d.front();
        q.pop();
        d.pop();
        if(vis[p]) continue;
        vis[p] = true;
        ans[p] = r;
        for(lli i = 0;i < g[p].size();i++){
            if(!vis[g[p][i]]) q.push(g[p][i]),d.push(r+1);
        }
    }
    for(lli i = 1;i <= n;i++) cout << i << " " << ans[i] << endl;
    return 0;
}