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 <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long ll;

#define MOD 1000000007

vector<int> g[100];

int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    int u, k;
    cin >> u >> k;
    u--;
    for (int j = 0; j < k; ++j) {
      int v;
      cin >> v;
      v--;
      g[u].push_back(v);
    }
  }
  vector<int> d(n, 1e9);
  queue<int> que;
  que.push(0);
  d[0] = 0;
  while (!que.empty()) {
    int v = que.front();
    que.pop();
    for (auto u : g[v]) {
      if (d[u] == 1e9) {
        que.push(u);
        d[u] = d[v] + 1;
      }
    }
  }
  for (int i = 0; i < n; ++i) {
    cout << i + 1 << " " << (d[i] == 1e9 ? -1 : d[i]) << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1e18;
const ll mod = 1000000007;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<class T> inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template<class T> inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
int ctoi(char c) {
  if (c >= '0' && c <= '9') {
    return c - '0';
  }
  return 0;
}
ll factorial(ll n) {
  if (n == 1) {
    return 1;
  }
  ll ans = factorial(n-1);
  return ans*n;
}
ll gcd(ll a, ll b) {
  if (a < b) {
    ll tmp = a;
    a = b;
    b = tmp;
  }
  ll r = a%b;
  while(r != 0) {
    a = b;
    b = r;
    r = a%b;
  }
  return b;
}
ll lcm(ll a, ll b) {
  return (a/gcd(a, b))*b;
}

int main() {
  ll n;
  cin >> n;
  vector <vector <bool>> v(n, vector <bool> (n, 0));
  vector <ll> color(n, 0);
  vector <ll> d(n, INF);
  queue <ll> q;
  rep(i, n) {
    ll a, b, c;
    cin >> a >> b;
    rep(j, b) {
      cin >> c;
      v.at(a-1).at(c-1) = 1;
    }
  }
  color.at(0) = 1;
  d.at(0) = 0;
  q.push(0);
  while (!q.empty()) {
    ll i = q.front();
    q.pop();
    rep(j, n) {
      if (v.at(i).at(j) && color.at(j)==0) {
        color.at(j) = 1;
        d.at(j) = d.at(i) + 1;
        q.push(j);
      }
    }
    color.at(i) = 2;
  }
  rep(i, n) {
    if (d.at(i) == INF) {
      cout << i+1 << ' ' << -1 << endl;
    } else {
      cout << i+1 << ' ' << d.at(i) << endl;
    }
  }
}

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

using namespace std;

int main(){
  queue<int> q;
  int n,k,u;
  int c[101];
  vector<int>  d[101];
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    d[u].resize(k);
    for(int j=0;j<k;j++) cin>>d[u][j];
  }
  for(int i=0;i<=n;i++) c[i]=-1;
  q.push(1);
  c[1]=0;
  int a;
  while(!q.empty()){
    a=q.front(),q.pop();
    for(int i=0;i<d[a].size();i++)
      if( d[a][i]>1 && c[d[a][i]]==-1){
	q.push(d[a][i]);
	c[d[a][i]]=c[a]+1;
      }
  }
  for(int i=1;i<=n;i++) cout<<i<<" "<<c[i]<<endl;
  return 0;
}

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

struct Node {
	int d = -1;
	bool flag = false;
	vector<int> v;
};

queue<int> s;

void bfs_s(vector<Node>& u, int id, int d)
{
	if (u[id].flag) return;

	u[id].d = d;
	u[id].flag = true;
	for (int i = 0; i < u[id].v.size(); i++)
	{
		s.push(u[id].v[i]);
	}
	return;
}

void bfs(vector<Node>& u)
{
	int d = 0;
	while(!s.empty())
	{
		int n = s.size();
		for (int i = 0; i < n; i++)
		{
			bfs_s(u, s.front(), d);
			s.pop();
		}
		d++;
	}
	return;
}

int main(void)
{
	int N, id, k, x;
	Node z;
	cin >> N;
	vector<Node> u(N + 1);
	for (int i = 0; i < N; i++)
	{
		cin >> id >> k;
		for (int j = 0; j < k; j++)
		{
			cin >> x;
			u[id].v.push_back(x);
		}
	}
	s.push(1);
	bfs(u);

	for (int i = 1; i <= N; i++) cout << i << " " << u[i].d << endl;

	return 0;
}

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

using namespace std;

vector<int> graph[100];
int dist[100]={0};
int main(){
  int n;
  cin >> n;

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

  queue<int> q;
  q.push(0);
  dist[0] = 0;
  while(!q.empty()){
    auto v = q.front();q.pop();
    for(auto next_v:graph[v]){
      if(dist[next_v]==-1){
        dist[next_v] = dist[v]+1;
        q.push(next_v);
      }
    }
  }
  for(int i=0;i<n;++i){
    cout << i+1 << " " << dist[i] << endl;
  }
}