Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

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


using namespace std;


static const  int N =  100;
static const  int no =  -2;

int graph[N][N] = {{}};
int d[N] = {};
int n;

void bfs(int v){
  queue<int> Q; 
  Q.push(v);

  int u;
    for(int i = 1;i <= n; i++){
      d[i] = no;
    
}
  d[v] = 0;

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

    for(int i = 1;i <= n; i++){
      if(graph[u][i] == 0) continue;
      if(d[i] != no) continue;
      d[i] = d[u] +1;
      Q.push(i);
    }
  }
}


int main(){
  int u,v,k;
  //graph
  cin >> n ;

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


  bfs(1);

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

  return 0;
}

C++: //16D8103013E Sen Shunkou
#include<iostream>
#include<queue>
int n;
int cnt=0;

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

    int cnt=0;
    int A[100][100];
    int dis_min[n];
    bool visited[n];

    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            A[i][j]=0;
        }
    }

    for(int i=0;i<n;i++){
        std::cin>>A[i][0];
        std::cin>>A[i][1];
        for(int j=0;j<A[i][1];j++){
            std::cin>>A[i][j+2];
        }
    }

    for(int i=0;i<n;i++){
        dis_min[i]=-1;
    }

    //initialization
    std::queue<int> que;
    que.push(0);
    //std::cout<<"\n"<<que.front()<<"\n";
    //std::cout<<que.size()<<"\n\n";

    while(!que.empty()){
        int q=que.size();
        for(int k=0;k<q;k++){
            //std::cout<<"quesize"<<que.size()<<"\n";
            int i=que.front();
            que.pop();
            visited[i]=true;
            dis_min[i]=cnt;
            //std::cout<<i<<"cnt"<<cnt<<"\n";
            if(A[i][1]!=0){
                for(int j=0;j<A[i][1];j++){
                    if(visited[A[i][j+2]-1]!=true){
                        visited[A[i][j+2]-1]=true;
                        que.push(A[i][j+2]-1);
                        //std::cout<<A[i][j+2]-1<<"\n";
                    }
                }
            }
        }
        cnt++;
        //std::cout<<"cnt="<<cnt<<"\n";
    }

    //std::cout<<"===========\n";
    for(int i=0;i<n;i++){
        std::cout<<i+1<<" "<<dis_min[i]<<"\n";
    }
    return 0;
}

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

using namespace std;

static const int MAX = 100;
static const int WHITE = 1;
static const int GRAY = 2;
static const int BLACK = 3;

class BFS {
private:
    int color[MAX];
    int n;
    int M[MAX][MAX];
    queue<int> Q;
    int distance[MAX];

public:
    BFS()
    {
        cin >> n;
        for(int i = 0; i < n; i++)
            for(int j = 0; j < n; j++)
                M[i][j] = 0;
        int vertex;
        int degree;
        for(int i = 0; i < n; i++)
        {
            color[i] = WHITE;
            cin >> vertex;
            cin >> degree;
            int to_v;
            for(int j = 0; j < degree; j++)
            {
                cin >> to_v;
                M[vertex - 1][to_v - 1] = 1;
            }
        }
    }

    void bfs()
    {
        for(int i = 0; i < n; i++)
            distance[i] = -1;

        distance[0] = 0;
        Q.push(0);
        color[0] = GRAY;
        while(Q.size() != 0)
        {
            int u = Q.front();
            Q.pop();
            color[u] = BLACK;
            for(int v = 0; v < n; v++)
            {
                if(M[u][v] && color[v] == WHITE)
                {
                    distance[v]  = distance[u] + 1;
                    Q.push(v);
                    color[v] = GRAY;
                }
            }
        }
    }

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

int main()
{
    BFS bfs;
    bfs.bfs();
    bfs.print();
}

C++: #include <iostream>
#include <stdio.h>
#include <queue>
#define N 101
#define INFTY (1<<21)


int n;
int M[N][N];
int d[N];

void bfs(int u) {
    std::queue<int> Q;
    Q.push(u);
    for (int i = 0; i < n; i++) d[i] = INFTY;
    d[u] = 0;
    while ( ! Q.empty() ) {
        int j = Q.front();
        Q.pop();
        for (int v = 0; v < n; v++) {
            if (M[j][v] == 0) continue;
            if (d[v] != INFTY) continue;
            d[v] = d[j] + 1;
            Q.push(v);
        }
    }
    for (int i = 0; i < n; i++) {
        printf("%d %d\n", i+1, d[i]);
    }
}

int main() {
    int u, k, v;
    scanf("%d", &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++) {
        scanf("%d %d", &u, &k);
        u--;
        if (k == 0) continue;
        for (int j = 0; j < k; j++) {
            scanf("%d", &v);
            v--;
            M[u][v] = 1;
        }
    }
    
    bfs(0);
    
    return 0;
}