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;
int M[101][101];
int n;
int d[101];

int search(int s){
    queue<int> Q;
    int u;

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

    while( !Q.empty() ){
	u=Q.front(); Q.pop();

	for(int i=1;i<=n;i++){
	    if(M[u][i]==0) continue;
	    if(d[i]>0) continue;
    
	    d[i]=d[u]+1;
	    Q.push(i);
	}

    }
}
    
int main(){
    int u,k,v;

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

    search(1);

    cout << 1 << " " << 0 << endl;
    for(int i=2;i<=n;i++){
	if(d[i]==0) cout << i << " " << -1 << endl;
	else cout << i << " " << d[i] << endl;
    }

    return 0;
}

C++: #include <iostream>
#include <queue>
#define INFTY -1
using namespace std;



int a[124][124] = {{}};
int d[124] = {};
int n;
void bfs(int k){
  queue <int> q;
  q.push(k);
  int u;


  while(!q.empty()){
    u = q.front(); q.pop();
    for(int v = 0;v < n;v++){
      if(a[u][v] == 0) continue;
      if(d[v] == INFTY) {
        d[v] = d[u] + 1;
        q.push(v);
        //cout << v << " " << d[v] << endl;
      }
    }

  }
}

int main(){

  int u,k,x;
  cin >> n;

d[0] = 0;
for(int i = 1; i < n;i++) d[i] = INFTY;

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

  bfs(0);

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

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;
}

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

class Vertex {
public:
    int num;
    bool flag;                  // 以前訪れたかどうか
    vector<int> adj;            // 隣接リスト
};

int dist[101];
void bfs(map<int, Vertex>& graph, Vertex s) {
    queue<Vertex> que;

    dist[s.num] = 0;
    que.push(s);
    while (!que.empty()) {
        Vertex u = que.front(); que.pop();
        for (auto i = 0; i < u.adj.size(); i++) {
            Vertex v = graph[u.adj[i]];
            if (!v.flag) {
                graph[u.adj[i]].flag = true;
                dist[v.num] = dist[u.num]+1;
                que.push(v);
            }
        }
    }
}

int main(void) {
    int n;
    cin >> n;
    for (int i = 0; i < 101; i++) {
        dist[i] = -1;
    }

    map<int, Vertex> graph; // 頂点の番号->頂点
    for (int i = 0; i < n; i++) {
        Vertex v;
        int num, k;
        cin >> num >> k;
        v.flag = false;
        v.num = num;
        for (int j = 0; j < k; j++) {
            int tmp;
            cin >> tmp;
            v.adj.push_back(tmp);
        }
        graph[num] = v;
    }

    bfs(graph, graph[1]);
    for (int i = 1; i <= n; i++) {
        cout << i << " " << dist[i] << endl;
    }

    return 0;
}

C++: #include <bits/stdc++.h>
 
using namespace std;

int main() {
    int n; cin >> n;
    vector<vector<int>> g(n);
    for (int i = 0; i < n; i++) {
        int u, k; cin >> u >> k; u--;
        while (k--) {
            int v; cin >> v; v--;
            g[u].push_back(v);
        }
        sort(g[u].begin(), g[u].end());
    }
    vector<int> d(n, -1);
    d[0] = 0;
    queue<int> q; q.push(0);
    while (q.size()) {
        int v = q.front(); q.pop();
        for (auto x : g[v]) {
            if (d[x] < 0) {
                d[x] = d[v] + 1;
                q.push(x);
            }
        }
    }
	for (int i = 0; i < n; i++) cout << i + 1 << " " << d[i] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;

struct Graph {
    enum Color {WHITE, GRAY, BLACK};
    vector<vector<int>> adj;
    vector<Color> color;
    vector<int> dist;
    Graph(int n) {
        adj.assign(n, vector<int>());
        color.assign(n, WHITE);
        dist.assign(n, -1);
    }
};

int main()
{
    int n;
    cin >> n;
    Graph g(n);
    for (int i = 0; i < n; i++) {
        int id, k;
        cin >> id >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            g.adj[id - 1].push_back(v - 1);
        }
    }

    queue<int> q;
    g.color[0] = Graph::GRAY;
    g.dist[0] = 0;
    q.push(0);
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        for (auto v : g.adj[u]) {
            if (g.color[v] == Graph::WHITE) {
                g.color[v] = Graph::GRAY;
                g.dist[v] = g.dist[u] + 1;
                q.push(v);
            }
        }
        g.color[u] = Graph::BLACK;
    }

    for (int i = 0; i < n; i++) {
        cout << (i + 1) << " " << g.dist[i] << endl;
    }
}

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

#define MAX_NODE 10000
#define INF 1000000000

using namespace std;

int d[MAX_NODE];
vector<int> adj[MAX_NODE];

int bfs(int n, int start){
	queue<int> que;
	for(int i=0;i<n;i++){
		d[i]=(i==start)?0:-1;
	}
	que.push(start);
	while(que.empty()==0){
		int from=que.front();
		que.pop();
		for(int i=0;i<adj[from].size();i++){
			int to=adj[from][i];
			if(d[to]==-1){
				d[to]=d[from]+1;
				que.push(to);
			}
		}
	}
}	

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

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
#include<queue>
using namespace std;
#define N 1000
bool M[N][N];

int main(){
    int n,u,k,v;
    queue<int> Q;

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

    int d[N]={0};
    Q.push(0);
    while(!Q.empty()){
        u=Q.front();
        Q.pop();
        for(int i=0;i<n;i++){
            if(M[u][i] && d[i]==0){
                d[i]=d[u]+1;
                Q.push(i);
            }
        }
    }

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

    return 0;
}