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>
#include<vector>
#include<queue>
#include<algorithm>

using namespace std;

int main() {
	int n, u, k, v;
	cin >> n;
	vector<int> ans(n,1000000000);
	vector<vector<int>> adj(n);
	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		while (k--)cin >> v, adj[u-1].push_back(v-1);
	}
	queue<pair<int, int>> q;//<idx,path>
	q.push(pair<int, int>(0, 1));
	while (!q.empty()) {
		auto tmp = q.front(); q.pop();
		ans[tmp.first] = min(ans[tmp.first], tmp.second);
		if (ans[tmp.first] != tmp.second)continue;
		for (int i = 0; i < adj[tmp.first].size(); i++) q.push(pair<int, int>(adj[tmp.first][i], tmp.second+1));
	}
	for (int i = 0; i < n; i++)	cout << i + 1 << " " << (ans[i] == 1000000000 ? -1 : ans[i]-1) << endl;
	
}

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

using namespace std;

int D[100100];//始点からの距離を入れる
int g[1001][1001]={{0}};//要素を0で初期化
void bfs(int src,int n){//srcは開始位置この場合だと頂点1だから0
  cerr << "bfs_root = " << src << endl;
  queue<int> Q;
  Q.push(src);
  D[src] = 0;
  while (! Q.empty()  ){
    int cur = Q.front();
    Q.pop();
    // cerr << "visiting_" << cur << " " <<D[cur] <<endl;
    for(int dst= 0; dst < n; dst++){
      if(g[cur][dst]==1 && D[dst]==0){
        D[dst]=D[cur]+1;
        Q.push(dst);
      }
    }
  }
}
void ans(int n){
  for (int i = 0; i < n; ++i)
  {
    cout << i+1 <<" "<<D[i]<<endl;
  }

}

int main(){
  // int g[1001][1001]={{0}};//要素を0で初期化
  int n,a,b,c;
  cin >> n;
  for (int i = 0; i < n; ++i)
  {
    cin >> a >> b ;
    for (int i = 0; i < b; ++i)
    {
      cin >> c;
      g[a-1][c-1]=1;/* code */
    }
  }
  bfs(0,n);
  ans(n);
  // for (int i = 0; i < n; ++i)
  // {
  //    for (int j = 0; j < n; ++j)
  //    {
  //     if (j==n-1)
  //     {
  //       cout << g[i][j] << endl;
  //     }else{
  //       cout << g[i][j] <<" ";
  //     }
  //    }
  // }


}

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

using namespace std;

typedef pair<int, int> E;

int INF = -1;

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

  int cnt = 0;
  int* visit = new int[n+1];
  for (int i = 1; i <= n; i++) {
    visit[i] = INF;
  }

  queue<E> q;
  q.push(E(1, cnt));
  while (q.size()) {
    E e = q.front();
    q.pop();
    if (visit[e.first] != INF)
      continue;
    visit[e.first] = e.second;

    int len = G[e.first][0];
    for (int i = 1; i <= len; i++) {
      q.push(E(G[e.first][i], e.second + 1));
    }
  }

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

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

using namespace std;

const int no_edge = -1;
const int edge = 1;
const int first_visit_label = 1;
const int no_distance = -1;

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

  vector<vector<int>> matrix_graph(
    vertex_num,
    vector<int>(vertex_num, no_edge)
  );

  for(int i = 0; i < vertex_num; i++) {
    int vertex_label;
    int adjacency_num;
    cin >> vertex_label >> adjacency_num;
    for(int j = 0; j < adjacency_num; j++) {
      int adjacency_label;
      cin >> adjacency_label;
      matrix_graph[vertex_label - 1][adjacency_label - 1] = edge;
    }
  }

  queue<int> will_visit_labels;
  vector<int> distances(vertex_num, no_distance);
  distances[first_visit_label - 1] = 0;
  will_visit_labels.push(first_visit_label);

  while(!will_visit_labels.empty()) {
    int current_label = will_visit_labels.front();
    will_visit_labels.pop();

    for(int i = 0; i < vertex_num; i++) {
      int will_visit_label = i + 1;
      if(matrix_graph[current_label - 1][will_visit_label - 1] == no_edge) {
        continue;
      }
      if(distances[will_visit_label - 1] != no_distance) {
        continue;
      }
      distances[will_visit_label - 1] = distances[current_label - 1] + 1;
      will_visit_labels.push(will_visit_label);
    }
  }

  for(int i = 0; i < vertex_num; i++) {
    cout << i + 1 << ' ' << distances[i] << endl;
  }
}

C++: #include<bits/stdc++.h>
#include<string>
#include<cctype>
#include<cmath>
#include<queue> 
#define rep(i,n) for(int i=0;i<(n);i++)
using namespace std;
 
int main(){
  queue <int> q1;
  int n,i,j;
  cin >> n;
  int d[n][n];
  rep(i,n){
    rep(j,n){
      if(i==j){
        d[i][j]=0;
      }else{
       d[i][j]=100000;
      }
    }
  }
  rep(i,n){
    int u,k;
    cin >> u >> k;
    q1.push(u);
    if(k>0){
     int v[k];
     rep(j,k){
       cin >> v[j];
       q1.push(v[j]);
     }
     int f = q1.front()-1;
     q1.pop();
     rep(i,k){
       int e=q1.front()-1;
       d[f][e]=1;
       q1.pop();
     }
    }else{
     q1.pop();
    }
  }

  rep(i,n){
    for(j=2;j<n;j++){
    d[0][i]=min(d[0][i],d[0][j]+d[j][i]);
    }
  }
 
 rep(i,n){
   cout << i+1 << ' ' <<d[0][i] << endl;
 }
 
  return 0;
}