Go: package main

import (
	"container/list"
	"fmt"
	"bufio"
	"os"
	"strconv"
)

const (
	N   = 100
	INF = 1 << 21
)

var (
	n        int
	adj      [N][N]int
	distance [N]int
)

func BFS(start int) {
	q := list.New()
	q.PushBack(start)
	for i := 0; i < n; i++ {
		distance[i] = INF
	}
	distance[start] = 0
	u := 0
	for q.Len() != 0 {
		u = q.Remove(q.Front()).(int)
		for v := 0; v < n; v++ {
			if adj[u][v] == 0 {
				continue
			}
			if distance[v] != INF {
				continue
			}
			distance[v] = distance[u] + 1
			q.PushBack(v)
		}
	}
	for i := 0; i < n; i++ {
		var d int
		if distance[i] == INF {
			d = -1
		} else {
			d = distance[i]
		}
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	var u, k, v int
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ = strconv.Atoi(scanner.Text())
		u -= 1
		scanner.Scan()
		k, _ = strconv.Atoi(scanner.Text())
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ = strconv.Atoi(scanner.Text())
			v -= 1
			adj[u][v] = 1
		}
	}
	BFS(0)
}

C++: #include<iostream>
#include<queue>
#include<vector>
#include<algorithm>
using namespace std;
int main(){
  
  int n,a,b,c,ans[101];
  vector<int> vec[101];
  queue<int> que;
  
  fill(ans,ans+101,105);
  ans[1] = 0;
  
  cin >> n;
  for(int i=0;i<n;i++){ 
    cin >> a >> b;
    for(int j=0;j<b;j++){
      cin >> c;
      vec[a].push_back(c);
    }
  }

  que.push(1);
  
  while(!que.empty()){
    
    int d = que.front();
    que.pop();
    
    for(int i=0;i<vec[d].size();i++){
      int e = vec[d][i];
      if(ans[e] > ans[d]+1){
	ans[e] = ans[d]+1;
	que.push(e);
      }
    }
    
  }
  for(int i=1;i<=n;i++){
    cout << i << ' ' ;
    if(ans[i]==105) cout << -1 << endl;
    else cout << ans[i] << endl;
  }
  return (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( void ){
  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;
}

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];//通过距离管理访问状态(color)

void bfs(int s){
    queue<int> q;//使用标准库中的queue
    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;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
static const int N = 100;

int n;
int M[N][N];
int vis[N];
int seq[N];

void bfs_print() {
	for (int i = 0; i < n; i++) {
		cout << i + 1 << ' ' << seq[i]<<endl;
	}
}

int main() {
	cin >> n;
	int u, k;
	int index;

	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;
		for (int j = 0; j < k; j++) {
			cin >> index;
			M[u - 1][index - 1] = 1;
		}
	}
	for (int i = 0; i < n; i++) {
		seq[i] = 0;
		vis[i] = 0;
		if(i >0) seq[i] = -1;
	}

	queue<int> q;
	seq[0] = 0;
	int t;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (M[i][j] == 1) {
				q.push(j);
			}
		}
		cout << endl;
		while (not q.empty()) {
			if (vis[q.front()] == 0) {
				seq[q.front()] = seq[i] + 1;
				vis[q.front()] = 1;
			}
			q.pop();
		}
	}

	bfs_print();
}
//
//void dfs_visit(int u) {
//	color[u] = GRAY;
//	d[u] = ++tt;
//	for (int v = 0; v < n; v++) {
//		if (M[u][v] == 1 && color[v] == WHITE) {
//			dfs_visit(v);
//		}
//	}
//	color[u] = BLACK;
//	f[u] = ++tt;
//}
//
//void dfs_print() {
//	for (int i = 0; i < n; i++) color[i] = WHITE;
//	tt = 0;
//	for (int i = 0; i < n; i++) {
//		if (color[i] == WHITE) {
//			dfs_visit(i);
//		}
//	}
//
//	for (int i = 0; i < n; i++) {
//		cout << i + 1 << ' ' << d[i] << ' ' << f[i] << endl;
//	}
//}
//

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

const int MAX_N = 100;
int to[MAX_N][MAX_N];
int ans[MAX_N];
bool visited[MAX_N];

int main() {
  int N;
  cin >> N;
  for (int i=0; i<N; i++) {
    for (int j=0; j<N; j++) {
      to[i][j] = -1;
    }
    ans[i] = -1;
    visited[i] = false;
  }
  for (int i=0; i<N; i++) {
    int tmp, n;
    cin >> tmp >> n;
    for (int j=0; j<n; j++) {
      int t;
      cin >> t; t--;
      to[i][j] = t;
    }
  }

  queue<pair<int, int> > que;
  que.push(make_pair(0, 0));
  while (!que.empty()) {
    pair<int, int> tmp = que.front(); que.pop();
    int x = tmp.first, depth = tmp.second;
    if (N < depth) continue;
    if (ans[x] == -1) {
      ans[x] = depth;
    } else {
      ans[x] = min(ans[x], depth);
    }
    for (int i=0; to[x][i] != -1; i++) {
      que.push(make_pair(to[x][i], depth + 1));
    }
  }

  for (int i=0; i<N; i++) {
    cout << i+1 << " " << ans[i] << endl;
  }
  return 0;
}

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

int main(int argc,char* argv[]){
  int dis[101],flag[101];
  vector<queue<int> > vec(101);
  int n,id,cnt,x,val=0;

  memset(dis,255,sizeof(dis));
  memset(flag,0,sizeof(flag));

  cin>>n;
  for(int i=0;i<n;i++){
    cin>>id>>cnt;
    queue<int> tmp;
    for(int l=0;l<cnt;l++){
      cin>>x;
      tmp.push(x);
    }
    vec[id]=tmp;
  }

  queue<int> que;
  que.push(1);
  while(!que.empty()){
    queue<int> tmp=que;
    while(!que.empty())
      que.pop();
    int p;

    while(!tmp.empty()){
      p=tmp.front();tmp.pop();
      if(dis[p]==-1)
	dis[p]=val;

      while(!vec[p].empty()){
	que.push(vec[p].front());
	vec[p].pop();
      }
    }
    val++;
  }

  for(int i=1;i<=n;i++)
    printf("%d %d\n",i,dis[i]);

  return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
using namespace std;
#define MAX 101

vector<int> G[MAX];

int bfs(int id){
	queue<int> Q;
	int temp[MAX] = {}, ans = -1;
	
	Q.push(1);
	
	while(!Q.empty()){
		int n = Q.front(); Q.pop();
		if(n == id){
			ans = temp[n];
			break;
		}
		for(int y : G[n]){
			if(temp[y]==0&&y!=1){
				temp[y] += temp[n] + 1;
				Q.push(y);
			}
		}
	}
	return ans;
}

int main(){
	int n, u, k, v, A[MAX][MAX] = {};
	
	cin>>n;
	
	for(int i = 0; i < n; i++){
		cin>>u>>k;
		for(int j = 0; j < k; j++){
			cin>>v;
			G[u].push_back(v);
		}
	}
	
	for(int i = 1; i <= n; i++){
		cout<<i<<" "<<bfs(i)<<endl;
	}
	
	
	return 0;
}