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 <deque>
#include <iostream>
#include <map>
#include <sstream>
#include <vector>

using namespace std;

deque<int> to_visit;
int t = 1;

int main() {
  int n;
  cin >> n;

  vector<bool> visited(n + 1, false);
  vector<int> dist(n + 1, -1);
  vector<vector<int>> V(n + 1);

  cin.ignore();

  for (string line; getline(cin, line);) {
    istringstream is{line};
    int id, n_nbrs, nbr;
    is >> id >> n_nbrs;
    vector<int> out_nbrs;
    while (is >> nbr)
      out_nbrs.push_back(nbr);
    V[id] = out_nbrs;
  }

  to_visit.push_back(1);
  dist[1] = 0;
  while (!to_visit.empty()) {
    if (visited[to_visit.front()]) {
      to_visit.pop_front();
      continue;
    }
    int curr = to_visit.front();
    to_visit.pop_front();
    visited[curr] = true;
    for (auto nbr : V[curr]) {
      if (dist[nbr] == -1)
        dist[nbr] = dist[curr] + 1;
      to_visit.push_back(nbr);
    }
  }

  for (int i = 1; i < V.size(); ++i) {
    cout << i << " " << dist[i] << endl;
  }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <stdio.h>
#include <cmath>
#include <map>
#include <queue>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
  int n;
  cin >> n;
  vector<vector<int>> Garph(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    rep(j, k) {
      int v;
      cin >> v;
      Garph[u-1].push_back(v-1);
    }
  }
  vector<int> dist(n, -1);
  queue<int> que;
  dist[0] = 0;
  que.push(0);
  while(!que.empty()) {
    int v = que.front();
    que.pop();
    for(auto next_v : Garph[v]) {
      if(dist[next_v] != -1) { continue;}
      dist[next_v] = dist[v] + 1;
      que.push(next_v);
    }
  }
  for(int i = 0; i < n; i++) {
    printf("%d %d\n", i+1, dist[i]);
  }
  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)
  }
}

C++: #include<iostream>
#include<vector>
#include<queue>
using namespace std;
int n,v[105],d[105];
vector<int>m[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(auto i:m[u])
        {
            int vv=i;
             if(!v[vv])
            {
                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=1;i<=n;i++)
    {
        int u,v,k;
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            cin>>v;
            m[u-1].push_back(v-1);
        }
    }
    bfs(0);
    for(int i=0;i<n;i++)cout<<i+1<<' '<<d[i]<<endl;
    return 0;
}

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

#define MAX 100
#define Q_MAX 50
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define INFTY -1

// d[i]は始点sから各頂点iまでの最短距離
int M[MAX][MAX], color[MAX], d[MAX], Q[Q_MAX], head, tail;

void enqueue(int x){
  //if(x == 18) cout << "head: " << head << ", tail: " << tail << endl;
  Q[tail] = x;
  if(tail + 1 == Q_MAX) tail = 0;
  else tail++;
}

int dequeue(){
  int x = Q[head];
  if(head + 1 == Q_MAX) head = 0;
  else head++;
  return x;
}

// 頂点番号は0-オリジン
void bfs(int n, int s){
  // 初期化
  head = 0;
  tail = 0;
  for(int i=0; i<n; i++){
    color[i] = WHITE;
    d[i] = INFTY;
  }

  color[s] = GRAY;
  d[s] = 0;
  enqueue(s);

  int u;
  while(head != tail){
    u = dequeue();
    //cout << "u: " << u+1 << endl;
    for(int v=0; v<n; v++){
      if(M[u][v] && color[v] == WHITE){
        color[v] = GRAY;
        d[v] = d[u] + 1;
        //cout << "v: " << v+1 << endl;
        enqueue(v);
      } 
    }
    color[u] = BLACK;
  }
}

int main(void){
  int n, u, k, v;
  cin >> n;

  // M[][]の初期化
  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--; // 頂点番号を0-オリジンにする。
    for(int j =0; j<k; j++){
      cin >> v;
      M[u][--v] = 1; // 頂点番号を0-オリジンにする。
    } 
  }

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

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

struct VRTX {
	int v[100] = {}, dist = -1;
};

int n, curdist = 0;
VRTX u[100];

void breadthFirstSearch(int x, int dist);

int main() {
	int i, j, id, dim;
	
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> id >> dim;
		for (j = 0; j < dim; j++) {
			cin >> u[id].v[j];
		}
	}

	breadthFirstSearch(1, 0);

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

	return 0;
}

void breadthFirstSearch(int x, int dist) {
	int i, nextdist;

	if (u[x].dist == -1)u[x].dist = dist;
	else if (u[x].dist == dist)return;
	else u[x].dist = min(u[x].dist, dist);
	
	i = 0;
	nextdist = u[x].dist + 1;
	while (u[x].v[i] != 0) {
		breadthFirstSearch(u[x].v[i], nextdist);
		i++;
	}
}