Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

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

using namespace std;

int n;
int u,k,t;
int d[100];
int dis=0;
int inf = -1;
vector<int> G[100];
queue<int> q;

void bfs(int x){
    q.push(x);
    while(!q.empty()){
        int u = q.front();q.pop();
        for(int i=0;i<G[u].size();i++){
            int v = G[u][i];
            if(d[v] == inf){
                d[v] = d[u] + 1;
                q.push(v);
            }
        }
    }
}

int main(){
    cin >> n;
    for(int i=0;i<n;i++){
        cin >> u >> k;
        u--;
        for(int j=0;j<k;j++){
            cin >> t;
            t--;
            G[u].push_back(t);
        }
    }
    fill(d,d+n,inf);
    d[0] = 0;
    bfs(0);
    for(int i=0;i<n;i++){
        cout << i+1 << " " << d[i] << endl;
    }
    return 0;
}

C++: #include<cstdio>
#include<queue>
using namespace std;
const char N_MAX = 105;
bool matrix[N_MAX][N_MAX];
char n;
char length = 0;
queue<char> que;
struct Node{
    char state;//0:undiscovered 1:active 2:end
    char path;
};
Node V[N_MAX];
char next(char num, char found){
    for(char i=found;i<n;i++){
        if(matrix[num][i]&&V[i].state==0){
            return i;
        }
    }
    return -1;
}
void buildMatrix(){
	for(char i=0; i<n;i++){
		int degree, index;
		scanf("%u%u", &index, &degree);
		for(char j=0; j<degree; j++){
			int temp;
			scanf("%d", &temp);
			matrix[index-1][temp-1] = true;
		}
	}
}

void bfs() {
    que.push(0);
    V[0].path = length = 0;
    V[0].state = 1;
    while(!que.empty()) {
        char active = que.front();
        char nex = next(active, 0);
        while(nex != -1) {
            que.push(nex);
            V[nex].path = V[active].path+1;
            V[nex].state = 1;
            nex = next(active, nex + 1);
        }
        V[active].state = 2;
        que.pop();
    }
}

int main(){
    scanf("%d", &n);
    for(char i=1;i<n;i++){
        V[i].path=-1;
    }
    buildMatrix();
    bfs();
    for(char i =0;i<n;i++){
        printf("%d %d\n", i+1, V[i].path);
    }
    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define reps(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
const ll mod = ll(1e9) + 7;
const int INF = int(1e9);
int main()
{
    int d[100][100];
    int N;
    cin>>N;
    rep(i,N){
        rep(j,N)d[i][j]=INF;
    }
    vector<int>edge(N);
    rep(i,N){
        int tmp;
        cin>>tmp;
        tmp--;
        int n;
        cin>>n;
        rep(j,n){
            int a;
            cin>>a;
            a--;
            d[tmp][a]=1;
        }
    }
    rep(i,N)d[i][i]=0;
    rep(k,N){
        rep(i,N){
            rep(j,N){
                d[i][j]=min(d[i][j],d[i][k]+d[k][j]);
            }
        }
    }
    rep(i,N){
        if(d[0][i]<INF){
            cout<<i+1<<" "<<d[0][i]<<endl;
        }else{
            cout<<i+1<<" "<<-1<<endl;
        }
    }

    return 0;
}

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

const int INF = 100000000;
int n;
int a[100][100], d[100];

int dist(int id) {
	int t = 0;
	queue<int> pd;

	for (int i = 0; i < n; i++)
		d[i] = INF;

	pd.push(1);
	d[0] = 0;

	while (pd.size()) {
		int id1 = pd.front();
		pd.pop();

		if (id1 == id)
			break;

		for (int i = 0; i < n; i++) {
			if (a[id1 - 1][i] && d[i] == INF) {
				pd.push(i + 1);
				d[i] = d[id1 - 1] + 1;
			}
		}
	}
	return d[id - 1];
}

int main()
{
	cin >> n;

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

	for (int i = 1; i < n + 1; i++) {
		int dmin = dist(i);
		cout << i << " " << dmin << endl;
	}

	return 0;
}

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

int main(){

  bool adj[100][100];
  int d[100];
  int n,u,v,k;

  cin >> n;
  for (int i=0; i<n; i++){
    cin >> u >> k;
    for (int j=0; j<k; j++){
      cin >> v;
      adj[u-1][v-1] = true;
    }
  }
  
  queue<int> q;
  bool pushed[100];
  q.push(1);
  pushed[1-1] = true;
  d[0] = 0;

  while(q.empty() == false){
    u = q.front();
    q.pop();
    for (int i=0; i<n; i++){
      if (adj[u-1][i]){
	if (pushed[i] != true){
	  d[i] = d[u-1] + 1;
	  q.push(i+1);
	  pushed[i] = true;
	}
      }
    }
  }
  
  cout << 1 << " " << 0 << endl;
  for (int i=1; i<n; i++){
    if (d[i] == 0)
      cout << i+1 << " " << -1 << endl;
    else
      cout << i+1 << " " << d[i] << endl;      
  }

}

C++: #include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <complex>
#include <stack>
#include <queue>
#include <list>
#include <utility>
#include <set>
using namespace std;

int main(){
    int n;
    cin >> n;
    int g[110][110];
    int i, j;
    int u, k, v;
    int dist[110];
    bool visited[110];
    
    for(i = 0; i < n; i++){
        dist[i] = -1;
        for(j = 0; j < n; j++){
            g[i][j] = 0;
        }
    }
    
    for(i = 0; i < n; i++){
        cin >> u >> k;
        u--;
        for(j = 0; j < k; j++){
            cin >> v;
            v--;
            g[u][v] = 1;
        }
    }
    
    queue<int> q1, q2;
    q1.push(0);
    
    for(i = 0; q1.size(); i++){
        while(!q1.empty()){
            int p = q1.front();
            q1.pop();
            
            if(visited[p]) continue;
            visited[p] = true;
            
            dist[p] = i;
            
            for(j = 0; j < n; j++){
                if(g[p][j]){
                    q2.push(j);
                }
            }
        }
        q1 = q2;
        while(!q2.empty()){
            q2.pop();
        }
    }
    
    for(i = 0; i < n; i++){
        printf("%d %d\n", i+1, dist[i]);
    }
}