Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

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

C++: #include <iostream>


using namespace std;

bool adjmatrix[101 * 101];
int costs[101];



void BFS(int vertex, int cur_cost, int N) {
  if (costs[vertex] < cur_cost) return;
  costs[vertex] = cur_cost;
  for (int i =1; i<= N; i++) {
    if(adjmatrix[vertex*101 + i]) {
      BFS(i, cur_cost + 1, N);
    }
  }
}
  

int main() {
  for (int i = 0; i < 101; i++) {
    costs[i] = 101;
  }
  int N;
  cin >> N;

  for (int i = 0; i < N; i++) {
    int vertex, degree;
    cin >> vertex >> degree;

    for (int j = 0; j < degree; j++) {
      int outvertex;
      cin >> outvertex;
      adjmatrix[vertex * 101 + outvertex] = true;
    }
  }


  /*
  //function to print adjmatrix
  for (int i = 0; i <= N; i++) {
    for (int j= 0; j <= N; j++) {
      if (adjmatrix[i * 101 + j]) {
	cout << "1 ";
      } else {
	cout << "0 ";
      }
    }
    cout << endl;
    }*/

  BFS(1, 0, N);

  for (int i =1; i<=N; i++) {
    if (costs[i] == 101) {
      cout << i << " " << -1 << endl;
    } else {
      cout << i << " " << costs[i] << endl;
    }
  }

 

}

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

int n = 0;
int u = 0;
int k[101];
int v[101][101];
int Short[101] = { 0 };
//into n = 0;
int p = 0;
int fptr = 0;
int lptr = 0;
int x1[10000];
int y1[10000];
void Enqueue(int y, int x)
{
	x1[lptr] = x;
	y1[lptr] = y;
	lptr = (lptr + 1) % n;
}
void bfs(int l) {
	int i;
	while (fptr!=lptr) {
		l=x1[fptr];
		p=y1[fptr];
		fptr = (fptr + 1) % n;
		if(Short[l]!=-1){
			continue;
		}
		for(i=0;i<k[l];i++){
			if(v[l][i]){
				Enqueue(p+1,v[l][i]);
			}
		}
		//Enqueue(v[l][in]);
		Short[l]=++p;
	}
}
int main()
{
	int i;
	int j;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> u;
		cin >> k[u];
		for (j = 0; j < k[u]; j++) {
			cin >> v[u][j];
		}
	}
	Enqueue(-1,1);
	for(i=0;i<n+1;i++){
		Short[i]=-1;
	}
	bfs(0);
	cout << "\n";
	
	for (i = 1; i < n + 1; i++) {
		cout << i << " " << Short[i] << endl;
	}
}

C++: #include<iostream>
#include<queue>
#include <limits>
using namespace std;
#define N 100

int inf = numeric_limits<int>::max();
int n, M[N][N], d[N];

void bfs(int s) {
    queue<int> q;
    q.push(s);
    for (int i; i<n; i++) {
        d[i] = inf;
    }
    d[s] = 0;
    int u;
    while (!q.empty()) {
        u = q.front(); // Get the first element
        q.pop();
        for (int v=0; v<n; v++) {
            if (M[u][v]==0) {
                continue;  
            }
            if (d[v]!=inf) {
                // Already visited
                continue;
            }
            d[v] = d[u] +1;
            q.push(v);
        }
    }
    for (int i=0; i<n; i++) {
        if (d[i]!=inf) {
            cout << i+1 << " " << d[i] << endl;
        } else {
            cout << i+1 << " " << -1 << endl;
        }
    }
}

int main() {
    int u, k, tmp;
    cin >> n;
    for (int i=0; i<n; i++) {
        for (int j=0; j<n; j++) {
            M[i][j] = 0;
        }
    }
    // Directed graph
    for (int i=0; i<n; i++) {
        cin >> u >> k;
        for (int j=0; j<k; j++) {
            cin >> tmp;
            M[u-1][tmp-1] = 1;
        }
    }

    bfs(0);
    return 0;
}

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

#define INFTY (1 << 30)

void BFS(bool mT[][100], int firstVerVal, int verNum, int distance[]) {
	queue<int>  verQ;
	verQ.push(firstVerVal);
	for (int i = 0; i < verNum; i++)
		distance[i] = INFTY;
	distance[firstVerVal] = 0;

	while (!verQ.empty()) {
		int curVerVal = verQ.front();
		verQ.pop();
		for (int i = 0; i < verNum; i++) {
			if (!mT[curVerVal][i] || distance[i] != INFTY) continue;
			distance[i] = distance[curVerVal] + 1;
			verQ.push(i);
		}
	}
}

int main() {
	bool matrixTable[100][100];
	int distance[100];
	int verNum;
	cin >> verNum;

	for (int i = 0; i < verNum; i++)
		for (int j = 0; j < verNum; j++)
			matrixTable[i][j] = false;
		
	for (int i = 0; i < verNum; i++) {
		int anyVerVal, anyVerNum;
		cin >> anyVerVal >> anyVerNum;
		for (int j = 0; j < anyVerNum; j++) {
			int verValue; cin >> verValue;
			matrixTable[anyVerVal - 1][verValue - 1] = true;
		}
	}

	BFS(matrixTable, 0, verNum, distance);

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

	return 0;
}

C++: #include<iostream>
#include<queue>
using namespace std;
int m[105][105],n,v[105],d[105];
void bfs(int s)
{
    v[s]=true;
    d[s]=0;
    queue<int>q;
    q.push(s);
    while(!q.empty())
    {
        int u=q.front();q.pop();
        for(int i=0;i<n;i++)
        {
             if(m[u][i]&&!v[i])
            {
                d[i]=d[u]+1;
                v[i]=true;
                q.push(i);
            }
        }
    }
}
int main()
{
    cin>>n;
    for(int i=0;i<n;i++)d[i]=-1;
    for(int i=0;i<n;i++)
    {
        int u,v,k;
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            cin>>v;
            m[u-1][v-1]=true;
        }
    }
    bfs(0);
    for(int i=0;i<n;i++)cout<<i+1<<' '<<d[i]<<endl;
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD=1000000007;
#define INF 1LL<<30
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()

vector<vector<int>> G;

// O(HW)
int n;
int d[110];
void bfs(){
    queue<int> que;
    
    que.push(0); // (0,0)スタート
    d[0]=0;
    while(!que.empty()){
        int p=que.front();
        que.pop();
        for(int nv : G[p]){
            if(d[nv]!=-1) continue;
            que.push(nv);
            d[nv]=d[p]+1;
        }
    }
}

int main() {
    
    cin>>n;
    G.resize(n);
    rep(i,n){
        int u,k;
        cin>>u>>k;
        u--;
        rep(j,k){
            int v;
            cin>>v;
            v--;
            G[u].push_back(v);
        }
    }

    rep(i,n) d[i]=-1;
    bfs();

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

}

C++: #include<bits/stdc++.h>
using namespace std;
int i,j,n,u,k,v,g[101][101],d[101],f[101];
int main(void){
  for(i=1;i<101;i++)d[i]=1<<30;
  d[1]=0;
  cin>>n;
  for(i=0;i<n;i++){
    cin>>u>>k;
    for(j=0;j<k;j++){
      cin>>v;
      g[u][v]++;
    }
  }
  queue<int>q;
  q.push(1);
  while(!q.empty()){
    u=q.front();q.pop();
    f[u]=1;
    for(i=1;i<101;i++){
      if(g[u][i]&&!f[i]){
        d[i]=min(d[i],d[u]+1);
        q.push(i);
      }
    }
  }
  for(i=1;i<=n;i++)cout<<i<<" "<<(d[i]==1<<30?-1:d[i])<<endl;
  return 0;
}