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++: /*
　　こんにちは。あたしはｶｳｶﾞｰﾙ。
　　redcoderになるためAtCoderを巡る旅をしてます。

　　　 　 ＿_
　　　 ヽ|＿_|ノ　　　　ﾓｫ
　　　　||‘‐‘||ﾚ　　_)_, ―‐ 、
　　　　/(Ｙ (ヽ＿ /・ ヽ　　 ￣ヽ
　　　　∠ ＿ ゝ　 ｀^ヽ ﾉ.::::_(ノヽ
　　　　 _/ヽ　 　　  /ヽ￣￣/ヽ
*/

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define dump(x) cout << #x << " = " << (x) << endl
#define YES(n) cout << ((n) ? "YES" : "NO") << endl
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl
#define POSSIBLE(n) cout << ((n) ? "POSSIBLE" : "IMPOSSIBLE") << endl
#define Possible(n) cout << ((n) ? "Possible" : "Impossible") << endl

#define rep(i, n) REP(i, 0, n)                  // 0, 1, ..., n-1
#define REP(i, x, n) for(int i = x; i < n; i++) // x, x + 1, ..., n-1
#define FOREACH(x, a) for(auto &(x) : (a))

#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()

#define COUT(x) cout << (x) << endl

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;
}

using Graph = vector<vector<int>>;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

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

    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 nv : G[v]) {
            if(dist[nv] != -1) continue;
            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }

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

C++: #include <iostream>
#include <queue>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <climits>
using namespace std;

const int MAX = 110;
int mat[MAX][MAX];
int dist[MAX], done[MAX];
int n;

void bfs(int s)
{
  int t = 0;
  queue<int> que;
  que.push(s);
  dist[s] = 0;
  while (!que.empty()) {
    int i = que.front(); que.pop();
    if (done[i]) continue;
    done[i] = 1;
    for (int j = 0; j < n; j++) {
      if (mat[i][j]) {
        dist[j] = min(dist[j], dist[i]+1);
        que.push(j);
      }
    }
  }
}

int main()
{
  cin >> n;

  memset(mat, 0, sizeof(mat));
  for (int i = 0; i < n; i++) {
    int u; cin >> u; u--;
    int k; cin >> k;
    for (int j = 0; j < k; j++) {
      int v; cin >> v; v--;
      mat[u][v] = 1;
    }
  }

  fill(dist, dist+MAX, INT_MAX);
  memset(done, 0, sizeof(done));
  bfs(0);
  for (int i = 0; i < n; i++)
    printf("%d %d\n", i+1, (dist[i]==INT_MAX?-1:dist[i]));

  return EXIT_SUCCESS;
}

C++: #include <iostream>
#include <vector>
#include <list>
#include <cstdlib>
#include <climits>

const int MAX_N = 100;

struct Node {
  int v;
  int d;
  bool visited;
};

int main(void) {
  std::cin.tie(0);
  std::ios::sync_with_stdio(false);  

  int n = 0;
  std::cin >> n;

  std::vector<std::vector<int> *> *graph = new std::vector<std::vector<int> *>(n + 1);
  std::vector<struct Node *> *nodes = new std::vector<struct Node *>(n + 1);
  
  for (int i = 1; i <= n; i++) {
    int v = 0;
    std::cin >> v;

    int k = 0;
    std::cin >> k;

    std::vector<int> *neighbors = new std::vector<int>(k);

    for (int j = 0; j < k; j++) {
      int a = 0;
      std::cin >> a;

      neighbors->at(j) = a;
    }

    graph->at(i) = neighbors;

    struct Node *node = (struct Node *) std::malloc(sizeof(struct Node));

    node->v = i;
    node->d = INT_MAX;
    node->visited = false;
    
    nodes->at(v) = node;
  }

  int count = 0;
  int start = 1;

  std::list<int> *stack = new std::list<int>();

  stack->push_back(nodes->at(start)->v);

  while (!stack->empty()) {
    std::vector<int> *newNodes = new std::vector<int>();

    while (!stack->empty()) {    
      int v = stack->front();
      stack->pop_front();

      if (count < nodes->at(v)->d) {
	nodes->at(v)->d = count;
      }
      
      nodes->at(v)->visited = true;
      
      std::vector<int> *neighbors = graph->at(v);

      for (std::vector<int>::iterator iterator = neighbors->begin(); iterator != neighbors->end(); ++iterator) {
	struct Node *node = nodes->at(*iterator);

	if (!node->visited) {
	  newNodes->push_back(node->v);
	}
      }
    }

    for (std::vector<int>::iterator iterator = newNodes->begin(); iterator != newNodes->end(); ++iterator) {
      stack->push_front(*iterator);
    }

    count++;
  }

  for (std::vector<struct Node *>::iterator iterator = nodes->begin() + 1; iterator != nodes->end(); ++iterator) {
    struct Node *node = *iterator;

    if (node->d == INT_MAX) {
      node->d = -1;
    }
        
    std::cout << node->v << " " << node->d << std::endl;
  }
  
  return 0;
}

C++: #include <bits/stdc++.h>
#define ll long long
#define INF 999999999
#define MOD 1000000007

using namespace std;

typedef pair<int,int>P;

const int MAX_N = 100;

vector<int> G[MAX_N];
int d[MAX_N];

int main()
{
	int n;
	cin >> n;
	for(int i=0;i<n;i++){
		int id;
		cin >> id;
		int k;
		cin >> k;
		for(int j=0;j<k;j++){
			int to;
			cin >> to;
			G[id-1].push_back(to-1);
		}
	}
	fill(d,d+n,INF);
	deque<int> bfs;
	bfs.push_back(0);
	d[0] = 0;
	while(!bfs.empty()){
		int v = bfs.front();
		bfs.pop_front();
		for(int i=0;i<G[v].size();i++){
			int to = G[v][i];
			if(d[to] > d[v]+1){
				d[to] = d[v]+1;
				bfs.push_back(to);
			}
		}	
	}
	for(int i=0;i<n;i++){
		if(d[i] == INF){
			d[i] = -1;
		}
		cout << i+1 << " " << d[i] << "\n";
	}
}