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;

typedef struct{
  int A[1000];
  int ans;
}node;
node T[1000];
int Q[1000000];
int head=0;
int tail=1;
int n;

void function(int num){
  while(true){
    if(head==tail)break;
    for(int i=1;i<=n;i++){
      if(T[num].A[i]==1){
	if(T[i].ans==0){
	  T[i].ans=T[num].ans+1;
	}
	Q[tail++]=i;
      }
    }
    num=Q[head++];
  }
  
}

int main(){
  int num;
  int son;
  int z;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>num;
    cin>>son;
    for(int j=0;j<son;j++){
      cin>>z;
      T[num].A[z]=1;
      }
  }
  for(int i=1;i<=n;i++){
    function(i);
  
  }
  for(int i=1;i<=n;i++){
      cout<<i<<" "<<T[i].ans<<endl;
  }


  return 0;
}

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

int BFS(int s, int t, const vector<vector<int> >& G){
    vector<int> stock1;
    vector<int> stock2;
    stock1.push_back(s);
    vector<int> check(101, 0);
    int d = 0;
    while (1) {
        for (int i = 0; i < stock1.size(); i++) {
            if (stock1[i] == t) return d;
            for (int j = 0; j < G[stock1[i]].size(); j++) {
                if (check[G[stock1[i]][j]] == 0) {
                    check[G[stock1[i]][j]] = 1;
                    stock2.push_back(G[stock1[i]][j]);
                }
            }
        }
        if (stock2.empty()) return -1;
        stock1.clear();
        stock1.swap(stock2);
        d++;
    }
}

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

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

using namespace std;

#define MAX 100
#define INF 1e9

int n;
int G[MAX][MAX];
int dist[MAX];

void bfs(){
  bool used[MAX];
  fill(dist,dist+n,INF);
  fill(used,used+n,false);
  dist[0] = 0;
  used[0] = true;

  queue<int> Q;
  Q.push(0);

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

    for(int i = 0 ; i < n ; i++){
      if(!used[i] && G[v][i]){
	used[i] = true;
	dist[i] = dist[v] + 1;
	Q.push(i);
      }
    }
  }
}

int main(){
  cin >> n;

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

  bfs();

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

  return 0;
}

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


//使用队列实现广度优先搜索

using namespace std;

static const int N=100;
static const int INFTY=(1<<21);

/**
 * M 邻接矩阵
 * queue 记录下一个待访问顶点的队列
 * 将七点s到各顶点的最短距离记录在d[i]中
 */

int n,M[N][N];
int 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?d[i]:(-1))<<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 i=0;i<n;i++){
            cin>>v;
            v--;
            M[u][v]=1;
        }
    }
    
    bfs(0);
    return 0;
}

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

bool A[110][110],flag[110];
int d[110];
int n;

void bfs(){
	queue<int> Q;
	Q.push(1);
	d[1]=0;
	while(Q.empty()==0){
		int u=Q.front();
		Q.pop();
		for(int i=2;i<=n;i++){
			if(A[u][i]==true && flag[i]==false ){
				flag[i]=true;
				Q.push(i);
				d[i]=d[u]+1;
			}
		}
	}
	for(int i=2;i<=n;i++) if(flag[i]==false) d[i]=-1;
	return ;
}

int main(){
	int a,b,c;
	cin>>n;
	for(int i=1;i<=n;i++){
		flag[i]=false;
			for(int j=1;j<=n;j++){
				A[i][j]=false;
		}
	}
	for(int i=1;i<=n;i++){
		cin>>a>>b;
		for(int j=1;j<=b;j++){
			cin>>c;
			A[a][c]=true;
		}
	}
	bfs();
	for(int i=1;i<=n;i++) cout<<i<<" "<<d[i]<<endl;	
	return 0;
}