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>

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<k;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 <cstdio>
#include <queue>
using namespace std;
#define INF (1<<21)

int n, G[100][100], dist[100], visited[100];


int main(void) {
    int u, k, v, i, j;
    scanf("%d", &n);
    for (i = 0; i < n; i++)
        for (j = 0; j < n; j++) G[i][j] = 0;

    for (i = 0; i < n; i++) {
        scanf("%d %d", &u, &k);
        u--;
        for (j = 0; j < k; j++) {
            scanf("%d", &v);
            v--;
            G[u][v] = 1;
        }
    }
    
    for (i = 1; i < n; i++) {
        dist[i] = INF;
        visited[i] = 0;
    }
    dist[0] = 0;
    visited[0] = 1;

    queue<int> q;
    q.push(0);
    while (!q.empty()) {
        u = q.front();
        q.pop();
        for (i = 0; i < n; i++) {
            if (G[u][i] == 0 || visited[i] == 1) continue;
            q.push(i);
            visited[i] = 1;
            dist[i] = dist[u] + 1;
        }
    }

    for (i = 0; i < n; i++) {
        if (dist[i] == INF) dist[i] = -1;
        printf("%d %d\n", i + 1, dist[i]);
    }

    return 0;
}

C++: //Breadth First Search
#include <iostream>
#include <queue>

using namespace std;

static const int N = 100;

int d[N];

void bfs(vector<vector<int>> &graph, int u) {
    queue<int> q;
    q.push(u);
    d[u] = 0;

    while(!q.empty()) {
        int v = q.front();
        q.pop();
        for (auto w: graph[v]) {
            if(d[w] != -1) continue;
            q.push(w);
            d[w] = d[v] + 1;
        }
    }
}

int main() {
    int n;
    cin >> n;
    int u, k, v;
    vector<vector<int>> graph(n);
    for(int i=0; i<n; i++) {
        cin >> u >> k;
        for(int j=0; j<k; j++) {
            cin >> v;
            graph[u-1].push_back(v-1);
        }
    }
    for(int i=0; i<n; i++) d[i] = -1;

    bfs(graph, 0);

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

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

#define N 100

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

queue<int> Q;

void bfs(int x){
    //初期化
    rep(i,n){
        d[i] = -1;
    }

    d[x] = 0;
    Q.push(x);

    while(!Q.empty()){
        int v = Q.front(); Q.pop();
        for(int i = 0; i < n; i++){
            if(M[v][i] == 1){
                if(d[i] == -1){
                    Q.push(i);
                    d[i] = d[v] + 1;
                }else{
                    d[i] = min(d[i], d[v] + 1);
                }
                
            }
        }
    }
}


int main(){
    cin >> n;

    rep(i,N)rep(j,N) M[i][j] = 0;

    int u, k, v;
    rep(i,n){
        cin >> u >> k;
        u--; //0オリジンに変換
        rep(j,k){
            cin >> v;
            v--; //0オリジンに変換
            M[u][v] = 1;
        }
    }

    bfs(0);

    rep(i,n){
        cout << i + 1 << " " << d[i] << endl;
    }

    return 0;
    
}

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

using namespace std;
int main(){
  int u, i, id, k, j;
  cin >> u;
  unordered_map<int, vector<int> > mymap;
  queue<vector<int> > myqueue;
  for (i = 0; i < u; ++i){
    cin >> id >> k;
    vector<int> points;
    for (j = 0; j < k; ++j){
      int a;
      cin >> a;
      points.push_back(a);
    }
    mymap[id] = points;
    if(id == 1){
      myqueue.push(points);
    }
  }
  
  bool visited[u+1];
  for (j = 1; j <= u; ++j){
    visited[j] = false;
  }
  visited[1] = true;

  int dist[u+1];
  for (j = 1; j <= u; ++j){
    dist[u] = -1;
  }
  dist[1] = 0;
  int d = 1;

  while(!myqueue.empty()){
    vector<int> combined;
    for (i = 0; i < myqueue.front().size(); ++i){
      if(!visited[myqueue.front()[i]]){
        dist[myqueue.front()[i]] = d;
        visited[myqueue.front()[i]] = true;
        if(combined.empty()){
          combined = mymap[myqueue.front()[i]];
        }else{
          combined.insert(combined.end(), mymap[myqueue.front()[i]].begin(), mymap[myqueue.front()[i]].end());
        }
      }
    }
    if(!combined.empty()){
      myqueue.push(combined);
    }
    myqueue.pop();
    d++;
  }

  for (j = 1; j <= u; ++j){
    cout << j << " " << dist[j] << endl;
  }

}

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

int main()
{
    queue<int> Q;
    int n;
    int a, b, c;
    cin >> n;
    int D[100], in[100][100];
    for (int i = 0; i < n; i++)
    {
        D[i] = -1;
        for (int j = 0; j < n; j++)
            in[i][j] = 0;
    }
    for (int i = 0; i < n; i++)
    {
        cin >> a >> b;
        for (int j = 0; j < b; j++)
        {
            cin >> c;
            in[c - 1][a - 1] = 1;
        }
    }
    Q.push(0);
    D[0] = 0;
    while (!Q.empty())
    {
        int cur = Q.front();
        Q.pop();
        for (int i = 0; i < n; i++)
        {
            if (in[i][cur] == 1 && D[i] == -1) {
                D[i] = D[cur] + 1;
                Q.push(i);
            }
        }
    }
    for (int i = 0; i < n; i++)
    {
        cout << i + 1 << " " << D[i] << endl;
    }
    return 0;
}

C++: #include <algorithm>
#include <iostream>
#include <math.h>
#include <stdio.h>
#include <string>
#include <sstream>
#include <vector>
#include <set>
#include <stack>
#include <map>
#include <cmath>
#include <queue>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;
typedef unsigned long long ll;
#define MAX_N 100
int d[MAX_N];

void init(){
	rep(i,MAX_N){
		d[i] = -1;
	}
}


int main()
{
	init();
	int n;
	cin>>n;
	vector<int> *node = new vector<int>[n];
	rep(i,n){
		int num,k;
		cin>>num>>k;
		rep(j,k){
			int num;
			cin>>num;
			num--;
			node[i].push_back(num);
		}
	}
	
	d[0] = 0;
	queue<int> que;
	que.push(0);
	while(que.empty() != true){
		int currentNode = que.front();
		que.pop();
		for(auto iter = node[currentNode].begin(); iter != node[currentNode].end(); iter++){
			if( d[*iter] == -1 || d[currentNode] + 1 < d[*iter]){
				d[*iter] = d[currentNode] + 1;
				que.push(*iter);
			}
		}
	}
	rep(i,n)cout<<i+1<<" "<<d[i]<<endl;
	return 0;
}