Go: package main

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

const MAX = 1000
const NIL = -1

type Node struct {
	id    int
	depth int
}

type Queue struct {
	head      int
	tail      int
	container [MAX]Node
}

func (q *Queue) inQueue(x Node) {
	q.container[q.tail] = x
	q.tail = (q.tail + 1) % MAX
}

func (q *Queue) deQueue() Node {
	x := q.container[q.head]
	q.head = (q.head + 1) % MAX
	return x
}

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

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()
	route := make([][]int, n)
	for i := range route {
		u, k := scanInt(), scanInt()
		u--
		route[u] = make([]int, k)
		for j := range route[u] {
			num := scanInt()
			num--
			route[i][j] = num
		}
	}

	d := make([]int, n)
	for i := range d {
		d[i] = NIL
	}

	start := Node{0, 0}
	que := Queue{}
	que.inQueue(start)
	for !que.isEmpty() {
		node := que.deQueue()
		if d[node.id] != NIL {
			continue
		}
		d[node.id] = node.depth

		for _, nextId := range route[node.id] {
			next := Node{id: nextId, depth: node.depth + 1}
			que.inQueue(next)
		}
	}

	for i, depth := range d {
		fmt.Println(i+1, depth)
	}
}

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

using namespace std;

const int INF = 100000000;

int main(){
	int n;
	cin >> n;
	vector<vector<int>> node(n+1);
	for(int i=0;i<n;i++){
		int u,k,tmp;
		cin >> u >> k;
		for(int j=0;j<k;j++){
			cin >> tmp;
			node[u].push_back(tmp);
		}
	}
	
	//search
	vector<int> res(n+1,INF);
	queue<int> que;
	queue<int> copied;
	queue<int> zeros;
	que.push(1);
	
	int count = 0;
	for(int i=0;i<n-1;i++){
		while(que.size()){
			int k = que.front(); que.pop();
			//cout << "-> " << k << endl;
			if(res[k] >= INF) res[k] = count;
			for(int v:node[k]){
				copied.push(v);
			}
		}
		count++;
		que = copied;
		copied = zeros;
	}

	//output
	for(int i=1;i<=n;i++){
		if(res[i] >= INF) res[i] = -1;
		cout << i << " " << res[i] << endl;
	}

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,l,n) for(int i=l; i<(int)(n); ++i)
#define REP(i,n) FOR(i,0,n)
using Graph = vector<vector<int>>;

int main() {
    int N; cin >> N;

    // グラフ入力受取 (ここでは無向グラフを想定)
    Graph G(N);
    REP(i,N){
        int u,k; cin >> u >> k;
        REP(i,k){
            int vlist; cin >> vlist;
            G[u-1].push_back(vlist-1);
        }
    }

    // BFS のためのデータ構造
    vector<int> dist(N, -1); // 全頂点を「未訪問」に初期化
    queue<int> que;

    // 初期条件 (頂点 0 を初期ノードとする)
    dist[0] = 0;
    que.push(0); // 0 を橙色頂点にする

    // BFS 開始 (キューが空になるまで探索を行う)
    while (!que.empty()) {
        int v = que.front(); // キューから先頭頂点を取り出す
        que.pop();

        // v から辿れる頂点をすべて調べる
        for (int nv : G[v]) {
            if (dist[nv] != -1) continue; // すでに発見済みの頂点は探索しない

            // 新たな白色頂点 nv について距離情報を更新してキューに追加する
            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }

    // 結果出力 (各頂点の頂点 0 からの距離を見る)
    for (int v = 0; v < N; ++v) cout << v+1 << " " << dist[v] << endl;
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;

vector< vector < int > > adjList;
vector< int > depths;

void bfs(void) {
  queue< int > currentLevel;
  queue< int > nextLevel;
  nextLevel.push(1);
  int depth = 0;
  while (nextLevel.size()) {
    while (nextLevel.size()) {
      currentLevel.push(nextLevel.front());
      nextLevel.pop();
    }
    while (currentLevel.size()) {
      if (depths[currentLevel.front()-1] == -1) {
	depths[currentLevel.front()-1] = depth;
	for (int i = 0; i < adjList[currentLevel.front()-1].size(); i++)
	  nextLevel.push(adjList[currentLevel.front()-1][i]);
      }
      currentLevel.pop();
    }
    depth++;
  }
}

int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  adjList = vector< vector < int > > (n, vector< int > ());
  depths = vector< int > (n, -1);
  for (int i = 0; i < n; i++) {
    int u, k;
    cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int holder;
      cin >> holder;
      adjList[i].push_back(holder);
    }
  }
  bfs();
  for (int i = 0; i < n; i++)
    cout << i+1 << ' ' << depths[i] << endl;
  return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <string.h>

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

using namespace std;

const int MAX_N = 100;

int n;
vector<int> adjlist[MAX_N];
int d[MAX_N];
queue<int> que;

void bfs() {
    int id = 1;

    d[id - 1] = 0;
    // for (int i = 0; i < (int) adjlist[id - 1].size(); i++) {
    //     int next_id = adjlist[id - 1][i];
    //     if (d[next_id - 1] < 0 || d[next_id - 1] > d[id - 1] + 1) {
    //         d[next_id - 1] = d[id - 1] + 1;
    //         que.push(next_id);
    //     }
    // }
    que.push(id);

    while (!que.empty()) {
        id = que.front();
        que.pop();

        for (int i = 0; i < (int) adjlist[id - 1].size(); i++) {
            int next_id = adjlist[id - 1][i];
            if (d[next_id - 1] < 0 || d[next_id - 1] > d[id - 1] + 1) {
                d[next_id - 1] = d[id - 1] + 1;
                que.push(next_id);
            }
        }
    }
}

int main(void) {
    cin >> n;

    for (int i = 0; i < n; i++) {
        int id, m;
        cin >> id >> m;
        for (int j = 0; j < m; j++) {
            int x;
            cin >> x;
            adjlist[id - 1].push_back(x);
        }
    }

    memset(d, -1, sizeof(d));
    bfs();

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

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
const int MOD =1e9+7;
using ll=long long;
using Graph = vector<vector<int>>;

int main() {
    int n; 
    cin >> n;
    Graph G(n);
    
    rep(i,n){
        int N; cin >> N; N--;
        int k; cin >> k;
        rep(j,k){
            int v; cin >> v; v--;
            G[N].push_back(v);
        } 
    }

    vector<int> dist(n, -1);
    queue<int> que;
    dist[0] = 0;
    que.push(0);

    while(!que.empty()){
        int v = que.front(); que.pop();

        for(int nv :G[v]){
            if(dist[nv] != -1) continue;

            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }
    rep(i,n){
        cout << i+1 <<" "<< dist[i] << endl;
    }
}

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

using namespace std;

#define N 100
#define INF -1

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

void bfs(int s){
	for(int i=0;i<n;i++){
		d[i] = INF;
	}
	int u,v;
	queue<int> q;
	q.push(s);
	d[s] = 0;
	while( !q.empty() ){
		u = q.front();
		q.pop();
		for(v=0;v<n;v++){
			if(d[v] != INF || m[u][v] != 1)continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	for(int i=0;i<n;i++){
		printf("%d %d\n",i+1,d[i]);
	}
}

int main(void){
	int u,k,v;
	for(int i=0;i<N;i++){
		for(int j=0;j<N;j++){
			m[i][j] = 0;
		}
	}
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		scanf("%d %d",&u,&k);
		u--;
		for(int j=0;j<k;j++){
			scanf("%d",&v);
			v--;
			m[u][v] = 1;	
		}
	}
	bfs(0);
	return 0;
}