Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

C++: #include<iostream>
#include<queue>
#include<vector>
using namespace std;
int main(){
  queue<int> q;
  int n,a,k,u,c[101];
  vector<int>  d[101];
  cin>>n;for(int i=0;i<n;i++){
    cin>>u>>k;c[i]=-1;
    d[u].resize(k);
    for(int j=0;j<k;j++) cin>>d[u][j];
  }q.push(1),c[1]=0;
  while(!q.empty()){
   a=q.front(),q.pop();
    for(int i=0;i<d[a].size();i++)
      if( d[a][i]>1 && c[d[a][i]]==-1) q.push(d[a][i]),c[d[a][i]]=c[a]+1;
  } for(int i=1;i<=n;i++) cout<<i<<" "<<c[i]<<endl;
  return 0;
}

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

#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

#define NO -1

using namespace std;


int adjacencyList[MAX + 1][MAX + 1];
int color[MAX + 1];
int d[MAX + 1];
int n;



void bfs(int o)
{
	queue<int> S;
	S.push(o);
	color[o] = GRAY;
	d[o] = 0;

	int fr;

	while (S.size() > 0) {
		fr = S.front();
		S.pop();
		color[fr] = BLACK;
		for (int i = 1; i <= n; i++) {
			if (color[i] == WHITE && adjacencyList[fr][i] != NO) {
				S.push(i);
				color[i] = GRAY;
				d[i] = d[fr] + 1;
			}
		}
	}

}

int main(void)
{

	int u;
	int k;
	int v;


	cin >> n;

	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			adjacencyList[i][j] = NO;
		}
	}

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

		for (int j = 0; j < k; j++) {
			cin >> v;
			adjacencyList[u][v] = 1;
		}

	}

	bfs(1);

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


	return 0;
}

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

#define INFTY (1 << 30)

void BFS(bool mT[][100], int firstVerVal, int verNum, int distance[]) {
	queue<int>  verQ;
	verQ.push(firstVerVal);
	for (int i = 0; i < verNum; i++)
		distance[i] = INFTY;
	distance[firstVerVal] = 0;

	while (!verQ.empty()) {
		int curVerVal = verQ.front();
		verQ.pop();
		for (int i = 0; i < verNum; i++) {
			if (!mT[curVerVal][i] || distance[i] != INFTY) continue;
			distance[i] = distance[curVerVal] + 1;
			verQ.push(i);
		}
	}
}

int main() {
	bool matrixTable[100][100];
	int distance[100];
	int verNum;
	cin >> verNum;

	for (int i = 0; i < verNum; i++)
		for (int j = 0; j < verNum; j++)
			matrixTable[i][j] = false;
		
	for (int i = 0; i < verNum; i++) {
		int anyVerVal, anyVerNum;
		cin >> anyVerVal >> anyVerNum;
		for (int j = 0; j < anyVerNum; j++) {
			int verValue; cin >> verValue;
			matrixTable[anyVerVal - 1][verValue - 1] = true;
		}
	}

	BFS(matrixTable, 0, verNum, distance);

	for (int i = 0; i < verNum; i++) {
		cout << i + 1 << " ";
		if (distance[i] == INFTY)
			cout << -1 << endl;
		else
			cout << distance[i] << endl;
	}

	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<cassert>
#include<cstdio>
#include<queue>
 
using namespace std;
 
int N, G[100][100], V[100], D[100];//G:２頂点,V:次数,D:距離
 
void bfs(int src){
    queue<int> Q;
    Q.push(src);
    fill(D, D + N, -1);
    D[src] = 0;
    while (! Q.empty()){
        int cur = Q.front();
        Q.pop();
        cerr << cur+1 << " " << D[cur] << endl;
        for (int k = 0; k < N; k++){
            if (G[cur][k] == 1 && D[k] == -1){
                D[k] = D[cur]+1;
                Q.push(k);
            }
        }
    }
}
 
int main(){
    scanf("%d", &N);
        int id, c;
        for (int i = 0; i < N; i++){
            scanf("%d", &id); id--;//配列は0から始まるので、頂点番号を-1して考える。
            scanf("%d", V + id);
            for (int j = 0; j < V[id]; j++){
                scanf("%d", &c); c--;//配列は0から始まるので、頂点番号を-1して考える。
                G[id][c] = 1;
            }
        }//データの読み込み完了。
    bfs(0);
}

C++: #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; 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;
}