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) {
			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 <queue>
using namespace std;

const long N = 100;
const long INFTY = (1<<21);

long n, M[N + 1][N + 1];
long d[N + 1];

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

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

	bfs(1);

	return 0;
}

C++: // Ref : https://book.mynavi.jp/ec/products/detail/id=35408

#include <iostream>
#include <queue>
#include <limits.h>

using namespace std;
static const int NMAX = 100;
int N, D[NMAX] = {};
bool G[NMAX][NMAX] = { { false } };

void breadthFirstSearch(int base) {
	int ix;
	for (int i = 0; i < N; i++) {
		D[i] = INT_MAX;
	}

	D[base] = 0;
	queue<int> q;
	q.push(base);
	while (!q.empty()) {
		ix = q.front(); q.pop();
		for (int i = 0; i < N; i++) {
			if (G[ix][i]) {
				q.push(i);
				if (D[ix] + 1 < D[i]) D[i] = D[ix] + 1;
			}
		}
	}

	for (int i = 0; i < N; i++) {
		cout << i + 1 << " " << ((D[i] == INT_MAX) ? (-1) : D[i]) << endl;
	}
}

int main() {
	int ix, deg, cache;
	cin >> N;

	for (int i = 0; i < N; i++) {
		cin >> ix >> deg;
		for (int j = 0; j < deg; j++) {
			cin >> cache;
			G[ix-1][cache-1] = true;
		}
	}

	breadthFirstSearch(0);

	return 0;
}

C++: #include <iostream>
#include <queue>
#include <stdio.h>

using namespace std;

int n, u, k, v;
int adjList[101][101];
int adjNum[101];
bool visited[101];

int lv[101];

queue<int> q;

void bfs(int entry_node) {
    lv[entry_node] = 0;
    q.push(entry_node);

    while (!q.empty()) {
        u = q.front(); q.pop();
        visited[u] = true;

        for (int i = 0; i < adjNum[u]; i++) {
            if (!visited[adjList[u][i]]) {
                if (lv[adjList[u][i]] == -1) {
                    lv[adjList[u][i]] = lv[u] + 1;
                }
                q.push(adjList[u][i]);
            }
        }
    }

}

int main () {
	scanf("%d", &n);

    for (int i = 0; i < n; ++i) {
        scanf("%d %d", &u, &k);
        adjNum[u-1] = k;
        for (int j = 0; j < k; ++j) {
            scanf("%d", &v);
            adjList[u-1][j] = v-1; // all IDs start from 1
        }

        visited[u-1] = false;
        lv[u-1] = -1; // set lv to -1 by default
    }

    bfs(0);
    for (int u = 0; u < n; ++u) {
        cout << u+1 << " " << lv[u] << "\n";
    }

	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], 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<iostream>
#include<queue>
using namespace std;
int M[101][101];
int n;
int d[101];

int search(int s){
    queue<int> Q;
    int u;

    Q.push(s);
    d[s]=0;

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

	for(int i=1;i<=n;i++){
	    if(M[u][i]==0) continue;
	    if(d[i]>0) continue;
    
	    d[i]=d[u]+1;
	    Q.push(i);
	}

    }
}
    
int main(){
    int u,k,v;

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

    search(1);

    cout << 1 << " " << 0 << endl;
    for(int i=2;i<=n;i++){
	if(d[i]==0) cout << i << " " << -1 << endl;
	else cout << i << " " << d[i] << endl;
    }

    return 0;
}

C++: #include <iostream>
#include <queue>
#define INFTY -1
using namespace std;



int a[124][124] = {{}};
int d[124] = {};
int n;
void bfs(int k){
  queue <int> q;
  q.push(k);
  int u;


  while(!q.empty()){
    u = q.front(); q.pop();
    for(int v = 0;v < n;v++){
      if(a[u][v] == 0) continue;
      if(d[v] == INFTY) {
        d[v] = d[u] + 1;
        q.push(v);
        //cout << v << " " << d[v] << endl;
      }
    }

  }
}

int main(){

  int u,k,x;
  cin >> n;

d[0] = 0;
for(int i = 1; i < n;i++) d[i] = INFTY;

  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> x;
      a[u - 1][x - 1] = 1;
    }
  }

  bfs(0);

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