Go: package main

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

type AdjacentList struct {
	matrix [][]int
}

func NewEmptyAdjacentList(dim int) *AdjacentList {
	matrix := make([][]int, dim)
	for i := 0; i < dim; i++ {
		matrix[i] = make([]int, dim)
	}
	return &AdjacentList{matrix: matrix}
}

func (al *AdjacentList) set(node int, adjacent int) {
	al.matrix[node-1][adjacent-1] = 1
}

func (al *AdjacentList) findAdjacentsFor(node int) []int {
	adjacents := []int{}
	for i, v := range al.matrix[node-1] {
		if v == 1 {
			adjacents = append(adjacents, i+1)
		}
	}
	return adjacents
}

type DistanceList struct {
	list []int
}

func NewDistanceList(dim int) *DistanceList {
	list := make([]int, dim)
	for i := 0; i < dim; i++ {
		list[i] = -1
	}
	return &DistanceList{list: list}
}

func (dl *DistanceList) set(node int, distance int) {
	dl.list[node-1] = distance
}

func (dl *DistanceList) get(node int) int {
	return dl.list[node-1]
}

func (dl *DistanceList) isVisited(node int) bool {
	return dl.list[node-1] >= 0
}

type Position struct {
	node     int
	distance int
}

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

	dim, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	al := NewEmptyAdjacentList(dim)

	for i := 1; i <= dim; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}

		adjacentNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		for j := 0; j < adjacentNum; j++ {
			adjacent, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			al.set(node, adjacent)
		}
	}

	dl := NewDistanceList(dim)

	bfs(al, dl)

	for i := 1; i <= dim; i++ {
		fmt.Printf("%d %d\n", i, dl.get(i))
	}
}

func bfs(al *AdjacentList, dl *DistanceList) {
	stack := []Position{Position{node: 1, distance: 0}}
	for len(stack) > 0 {
		currentPosition := stack[0]
		stack = stack[1:]
		if !dl.isVisited(currentPosition.node) {
			dl.set(currentPosition.node, currentPosition.distance)
		}
		for _, v := range al.findAdjacentsFor(currentPosition.node) {
			if !dl.isVisited(v) {
				stack = append(stack, Position{node: v, distance: currentPosition.distance + 1})
			}
		}
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

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

const int nIMPOS = -1;
struct StDist
{
  int m_nDist;
  int m_nFromMeTo;

  StDist(int nDist) : m_nDist(nDist), m_nFromMeTo(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<StDist>& rvoDist)
{
  int nxSiz;
  cin >> nxSiz;

  rvvnAdjcy.resize(nxSiz + 1, vector<int>(nxSiz + 1, 0));
  for (int i = 0; i < nxSiz; ++i)
  {
    int nx, nySiz;
    cin >> nx >> nySiz;
    for (int j = 0; j < nySiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  StDist oDist(nIMPOS);
  rvoDist.resize(nxSiz + 1, oDist);
}

void fnBreadthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, 
                          queue<int>& rqnBFSrch, vector<StDist>& rvoDist)
{
  while (rqnBFSrch.size())
  {
    int nx = rqnBFSrch.front(); rqnBFSrch.pop();
    if (rvoDist[nx].m_nDist == nIMPOS)  continue;
    if (rvoDist[nx].m_nFromMeTo == 1 )  continue; 

    rvoDist[nx].m_nFromMeTo = 1;
    for (int ny = 1; ny < cnrvvnAdjcy[nx].size(); ++ny)
      if (cnrvvnAdjcy[nx][ny] == 1)
      {
        int nDist = rvoDist[nx].m_nDist + 1;
        if (rvoDist[ny].m_nDist == nIMPOS)
          rvoDist[ny].m_nDist = nDist;
        else
          rvoDist[ny].m_nDist = min(rvoDist[ny].m_nDist, nDist);

        rqnBFSrch.push(ny);
      }
  }
}

void fnResult(const vector<StDist>& cnrvoDist)
{
  for (int i = 1; i < cnrvoDist.size(); ++i)
    cout << i <<  " " << cnrvoDist[i].m_nDist << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  queue<int>  qnBFSrch;
  vector<StDist> voDist;

  fnInput(vvnAdjcy, voDist);

  voDist[1].m_nDist = 0;
  qnBFSrch.push(1);
  fnBreadthFirstSearch(vvnAdjcy, qnBFSrch, voDist);
  fnResult(voDist);

  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#define Lens 105
using namespace std;
int N;
int A[Lens][Lens];
int d[Lens];
char c[Lens];
queue<int> Q;

int main()
{
	cin >> N;
	for (int i = 1; i <= N; i++)
	{
		int k, n;
		cin >> k >> n;
		c[k] = 'w';
		for (int i = 0; i < n; i++)
		{
			int j;
			cin >> j;
			Q.push(j);
			A[k][j] = 1;
		}
	}
	int j = Q.front();
	for (int i = 1; i <= N; i++)
	{
		while (A[i][j] == 1 && c[j] == 'w')
		{
			Q.pop();
			d[j] = d[i] + 1;
			c[j] = 'g';
			if (Q.size() == 0)
				break;
			j = Q.front();
			while (c[j] == 'g')
			{
				Q.pop();
				if (Q.size() == 0)
					break;
				j = Q.front();
			}

		}

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

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

using namespace std;

vector<int> G[110];

const int INF=1e9;

int d[110];
bool used[110];

void bfs(int x)
{
    fill(d,d+110,INF);
    d[x]=0;

    queue<pair<int,int> > q;

    q.push(make_pair(0,x));

    used[x]=true;

    while(!q.empty())
    {
        pair<int,int> tmp=q.front();q.pop();

        int dd=tmp.first,now=tmp.second;
        for(int i=0;i<G[now].size();i++)
        {
            if(!used[G[now][i]])
            {
                d[G[now][i]]=dd+1;
                q.push(make_pair(dd+1,G[now][i]));
                used[G[now][i]]=true;
            }
        }
    }
}


int main()
{
    int n;

    cin>>n;

    for(int i=0;i<n;i++)
    {
        int a,b,c;

        cin>>a>>b;

        for(int j=0;j<b;j++)
        {
            cin>>c;

            G[a].push_back(c);
        }
    }

    bfs(1);

    for(int i=1;i<=n;i++)
    {
        cout<<i<<" ";

        if(d[i]==INF)
        {
            cout<<"-1";
        }else
        {
            cout<<d[i];
        }
        cout<<endl;
    }

    return 0;
}

C++: /**
 * Bredth first search.
 */

#include <iostream>
using namespace std;
const int N = 101;
int adj[N][N] = {0};
int d[N]={-1};

void bfs(int n, int dd) {
	int k = adj[n][0];
	d[n] = dd++;
	for (int j=1;j<=k;j++) {
		bfs(adj[n][j], dd);
	}
}

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

	bfs(1, 0);

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

	return 0;
}

C++: #include<stdio.h>
struct
{
    int Q[10000];
    int head=0,last=0;
    void push_Back(int x)
    {
        Q[last]=x;
        last=(last+1)%10000;
    }
    int pop()
    {
        int x=Q[head];
        head=(head+1)%10000;
        return x;
    }
    bool Empty()
    {
     return head==last;
    }
}myqueue;
const int N=100;
const int nil=10000000;
int n;
int tu[N][N];
int juli[N];
void BFS()
{
    for (int i=0;i<n;i++)
        juli[i]=nil;
  myqueue.push_Back(0);
  juli[0]=0;
  int u;
  while(!myqueue.Empty())
  {
      u=myqueue.pop();
      for (int v=0;v<n;v++)
      {
          if(tu[u][v]==0) continue;
          if(juli[v]!=nil) continue;
          juli[v]=juli[u]+1;
          myqueue.push_Back(v);
      }
  }
  for (int i=0;i<n;i++)
  {
      printf("%d %d\n",i+1,((juli[i]==nil)?(-1):juli[i]));
  }
}
int main()
{
    int u,v,k;
    scanf("%d",&n);
    for (int i=0;i<n;i++)
    {
        scanf("%d%d",&u,&k);
        u--;
        for (int j=0;j<k;j++)
        {
            scanf("%d",&v);
            v--;
            tu[u][v]=1;
        }
    }
    BFS();
    return 0;
}