Go: package main

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

type Pair struct {
	v int
	d int
}

type Queue []Pair

func (q *Queue) push(v Pair) {
	*q = append(*q, v)
}

func (q *Queue) pop() Pair {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	nVerts := scanInt(sc)
	graph := make([][]int, nVerts+1)

	for i := 0; i < nVerts; i++ {
		u := scanInt(sc)
		nDegrees := scanInt(sc)

		graph[u] = make([]int, nDegrees)
		for d := 0; d < nDegrees; d++ {
			graph[u][d] = scanInt(sc)
		}
	}

	paths := make([]int, nVerts+1)

	queue := Queue(make([]Pair, 0))
	queue.push(Pair{1, 1})
	paths[1] = 1

	for len(queue) > 0 {
		p := queue.pop()
		d := p.d + 1
		for _, v := range graph[p.v] {
			if paths[v] == 0 {
				paths[v] = d
				queue.push(Pair{v, d})
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= nVerts; i++ {
		fmt.Fprintf(w, "%d %d\n", i, paths[i]-1)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

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

using namespace std;

vector <int> adj[105];
int level[105];
int visited[105];

void bfs()
{
    for(int i = 0; i < 105; i++)
        level[i] = -1;

    queue <int> q;
    q.push(1);
    visited[1] = 1;
    level[1] = 0;

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

        for(int i = 0; i < adj[u].size(); i++)
        {
            int v = adj[u][i];

            if(!visited[v]) {
                visited[v] = 1;
                level[v] = level[u] + 1;
                q.push(v);
            }
        }
    }
}

int main()
{
    int node, vertice, edge, vertex, u, v, i, j;

    cin >> node;

    for(i = 0; i < node; i++)
    {
        cin >> vertice >> edge;
        for(j = 0; j < edge; j++) {
            cin >> vertex;
            adj[vertice].push_back(vertex);
        }
    }

    bfs();

    for(i = 1; i <= node; i++) {
        cout << i << " " << level[i] << endl;
    }

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0, i##_len = (n); i < i##_len; ++i)
#define rep2(i, x, n) for(int i = x, i##_len = (n); i < i##_len; ++i)
#define all(n) begin(n), end(n)
using ll = long long;
using P = pair<int, int>;
using vi = vector<int>;
using vl = vector<ll>;
using vs = vector<string>;
using vc = vector<char>;
using vb = vector<bool>;
using vd = vector<double>;
vi dir = {-1, 0, 1, 0, -1, -1, 1, 1, -1};

int main() {
  int n;
  cin >> n;
  vector<vi> g(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    rep(j, k) {
      int u;
      cin >> u;
      u--;
      g[i].push_back(u);
    }
  }
  vi ans(n, -1);
  ans[0] = 0;
  queue<int> q;
  q.push(0);
  while(!q.empty()) {
    int i = q.front();
    q.pop();
    for(int v : g[i]) {
      if(ans[v] != -1) continue;
      ans[v] = ans[i] + 1;
      q.push(v);
    }
  }
  rep(i, n) cout << i + 1 << ' ' << ans[i] << endl;
}

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

int main(){
  int n;
  cin>>n;
  int a[110][110] = {};
  for(int i=1;i<=n;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0;j<k;j++){
      int v;
      cin>>v;
      a[i][v]=1;
    }
  }

  int d[110];
  for (int i=1;i<=n;i++){
    d[i]=-1;
  }
  queue<int> q;
  d[1]=0;
  q.push(1);
  while(! q.empty()){
    int cur =q.front();
    q.pop();
    for(int i=1;i<=n;i++){
      if(a[cur][i]==1 && d[i]==-1){
	d[i]=d[cur]+1;
	q.push(i);
      }
    }
  }
  for(int i=1;i<=n;i++){
    cout<<i<<" "<<d[i]<<endl;
  }
}

C++: #include <cstdio>
#include <cstring>
#include <queue>
#define N 110
#define INF 0x3f3f3f3f
using namespace std;
//stack<int> s;
int n;
int m[N][N];
int used[N];
int d[N];
void bfs(int root){
    queue<int>q;
    while(!q.empty()) q.pop();
    q.push(root);
    d[root] = 0;
    while(!q.empty()){
        int u = q.front();
        used[u] = 1;
        q.pop();
        for(int i = 1; i <= n; i++){
            if(used[i] == 0 && m[u][i]){
                q.push(i);
                d[i] = d[u] + 1;
                used[i] = 1;
            }
        }
    }
}
int main(){
    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++) used[i] = 0;
    for(int i = 0; i < N; i++) d[i] = INF;
    scanf("%d", &n);
    for(int p = 0; p < n; p++){
        int node, k;
        scanf("%d %d", &node, &k);
        for(int i = 0; i < k; i++){
            int b;
            scanf("%d", &b);
            m[node][b] = 1;
        }
    }
    for(int i = 1; i <= n; i++) if(used[i] == 0) bfs(i);
    for(int i = 1; i <= n; i++){
        printf("%d %d\n", i, d[i]);
    }
    return 0;
}

C++: #include <stdio.h>
#include <string.h>
#include<iostream>
#include<queue>
using namespace std;

char s[13][1];
int D[106][106];
int A[106],f[106],w,h,n,sx,sy,gx,gy,e,g[106];
int   kensa(int ,int);
int main(){
	queue<int> P;
	int i,j,a,b,c,d;
	for(i=1;i<=100;i++){
		for(j=1;j<=100;j++){
			D[i][j]=-1;		
		}					
	}						
	for(i=1;i<=100;i++){		
		A[i]=0;				
		f[i]=-1;
		g[i]=0;
	}							
	scanf("%d" ,&a);//     a=4
	for(i=1;i<=a;i++){
        scanf("%d",&b);		//
		scanf("%d",&b);			//b=2					//
		for(j=1;j<=b;j++){		//
		scanf("%d",&c);			//					//
		D[i][c]=1;
//
		}						//D[???][???]
	}				
	for(i=1;i<=a;i++){
		for(j=1;j<=a;j++){
	//		printf("%d %d %d\n",i,j,D[i][j]);
		}	
	}//
	P.push(1);
	//P???1
	f[1]=0;
	while(!P.empty()){			//
		d=P.front();
		//
		A[d]=1;
		//
		P.pop();				//
		for(i=1;i<=a;i++){
			//printf("%d %d %d\n",d,i,D[d][i]);//
			if(D[d][i]==-1){		//
			continue;			//
			}					//
			if(A[i]==1){		//
			continue;			//
			}					//
			P.push(i);			//
			
			g[i]=g[d]+1;
			f[i]=g[d]+1;
			A[i]=1;
			//printf("%d\n",P.back());
		}	
	}							//
	for(i=1;i<=a;i++){			//
	printf("%d %d\n",i, f[i]);	//
	}
	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() {
  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 <bits/stdc++.h>
using namespace std;

#define MAX 100
int n;
int M[MAX][MAX];
int dist[MAX];

void bfs(int);

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

void bfs(int s){
  queue<int> q;
  int u,v;
  int i;
  q.push(s);
  for(i = 0; i < n; i++){
    dist[i] = INFINITY;
  }
  dist[s] = 0;
  while( !q.empty() ){
    u = q.front();
    q.pop();
    //for(i = 0; i < n; i++){
      for(v = 0; v < n; v++){
        if(M[u][v] == 0){
          continue;
        }
        if( dist[v] != INFINITY){
          continue;
        }
        dist[v] = dist[u] + 1;
        q.push(v);
      }
  }
  for(i = 0; i < n; i++){
    cout << i+1 << " " << ( (dist[i] == INFINITY) ? (-1) : dist[i] ) << endl;
    //if( d[i] == INFINITY)
  }
}