Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, &g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

func fillDistancesByBreadthFirstSearch(g *DirectedGraph, startNode *DirectedGraphNode) {
	startNode.visited = true
	startNode.d = 0

	queue := Queue{}
	queue.enqueue(startNode)
	for !queue.isEmpty() {
		u := queue.dequeue().node
		for _, adjacent := range u.adjacents {
			if !adjacent.visited {
				adjacent.visited = true
				adjacent.d = u.d + 1
				adjacent.parent = u
				queue.enqueue(adjacent)
			}
		}
		u.visited = true
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	// fmt.Println(g)
	fillDistancesByBreadthFirstSearch(g, &g.nodes[1])
	// fmt.Println(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		distance := node.d
		if distance == infty {
			distance = -1
		}
		fmt.Println(node.key, distance)
	}
}

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

#define N 101
#define WHITE 0
#define GRAY 1
#define BLACK 2

int Q[N], M[N][N], color[N], d[N], f = 1, c = 1;

void Enqueue(int n) {
  Q[f] = n;
  f++;
  if ( f == N ) f = 1;
}

int Dequeue() {
  int x = c;
  c++;
  if ( c == N ) c = 1;
  return Q[x];
}

void BFS ( int s ) {
  int u;
  for ( int i = 1; i <= N; i++ ) {
    color[i] = WHITE;
    d[i] = -1;
  }
  color[s] = GRAY;
  d[s] = 0;
  Enqueue(s);
  while(f!=c ) {
    u = Dequeue();
    for ( int i = 1; i <= N; i++ ) {
      if ( color[i] == WHITE && M[u][i] == 1 ) {
	color[i] = GRAY;
	d[i] = d[u] + 1;
	Enqueue(i);
      }
    }
    color[u] = BLACK;
  }
}

int main() {
  int n,u,k,v;
  for ( int i = 1; i < N; i++ ) {
    for ( int j = 1; j < N; j++ ) {
      M[i][j] = 0;
    }
  }
  cin >> n;
  for ( int i = 1; i <= n; i++ ) {
    cin >> u >> k;
    for ( int j = 0; j < k; j++ ) {
      cin >> v;
      M[u][v] = 1;
    }
  }
  BFS(1);
  for ( int i = 1; i <= n; i++ ) {
    cout << i << " " << d[i] << endl;
  }
  return 0;
}

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

int G[123][123];
int dis[123];
int n;

struct st {
  int pos;
  int v;
};

int main() {
  ios::sync_with_stdio(false);
  cin >> n;
  for(int i = 1; i <= n; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    for(int j = 0; j < v; j++) {
      int t;
      scanf("%d", &t);
      G[u][t] = G[t][u] = 1;
    }
  }

  memset(dis, 0x3f, sizeof dis);

  int start = 1;
  queue<st> q;
  q.push((st) {
    1, 0
  });

  while(!q.empty()) {

    st u = q.front();
    q.pop();
    dis[u.pos] = u.v;

    for(int i = 1; i <= n; i++) {
      if(i == u.pos) continue;
      if(G[i][u.pos] == 0) continue;
      if(dis[i] <= u.v) continue;
      q.push((st){i, u.v + 1});
    }
  }

  for(int i=1;i<=n;i++) {
    printf("%d %d\n", i, dis[i] > 100000 ? -1 : dis[i]);
  }

  return 0;
}

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

using namespace std;

const int INF = 1e9;

int main(void) {
    int n, u, k ,v, G[110][110] = {}, d[110];
    cin >> n;

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

    fill(d, d + 110, INF);
    d[1] = 0;

    queue<int> q;
    q.push(1);
    while (q.size()) {
        int f = q.front(); q.pop();

        for (int i = 1; i <= n; i++) {
            if (!G[f][i] || d[i] != INF) continue;
            d[i] = d[f] + 1;
            q.push(i);
        }
    }

    for (int i = 1; i <= n; i++)
        cout << i << " " << ((d[i] == INF) ? -1 : d[i]) << endl;

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <unordered_map>
#include <queue>
#include "../cxx-prettyprint/prettyprint.hpp"


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

    std::unordered_map<int, std::vector<int>> Adj(n);

    for (int i = 0; i < n; i ++) {
        int u, k;
        std::cin >> u >> k;
        std::vector<int> V(k);
        for (int& v : V) {
            std::cin >> v;
        }
        Adj[u] = V;
    }

    std::set<int> nodes_unvisited;
    std::unordered_map<int, int> distances;

    for (int i = 1; i <= n; i ++) {
        nodes_unvisited.insert(i);
    }

    nodes_unvisited.erase(1);
    distances[1] = 0;
    std::queue<int> queue;
    queue.push(1);

    while (!queue.empty()) {
        int u = queue.front();
        queue.pop();
        for (int v : Adj[u]) {
            if (nodes_unvisited.find(v) != nodes_unvisited.end()) {
                nodes_unvisited.erase(v);
                distances[v] = distances[u] + 1;
                queue.push(v);
            }
        }
    }

    for (int i = 1; i <= n; i ++) {
        std::cout << i << " " << distances[i] << std::endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define white 0
#define gray 1
#define black 2


int n;
int M[100][100];
int d[100],color[100];

void bfs(int u) {
  
  queue<int> Q;
  Q.push(u);
  color[u] = gray;
  while(!Q.empty()) {
    int q = Q.front();
    for(int i = 0;i < n;i++) {
      if(M[q][i] && color[i] == white) {
        Q.push(i);
        d[i] = d[q] + 1;
        color[i] = gray;
      }
    }
    Q.pop();
    color[q] = black;
  }
}

int main() {


  cin >> n;

  for(int i = 0;i < n;i++) {
    d[i] = 0;
    color[i] = white;
    for(int j = 0;j < n;j++) {
      M[i][j] = 0;
    }
  }
  

  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--;
      M[u][v] = 1;
    }
  }

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

}