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 <vector>
#include <stack>
#include <queue>
#include <utility>

using vvi = std::vector<std::vector<int>>;

std::vector<int> DistanseFrom(const vvi& edges, int from)
{
    using namespace std;
    constexpr int nil = -1;

    int nextDist {};
    const int n = edges.size();
    queue<int> currentQ;
    queue<int> nextQ;
    vector<int> distances(n, nil);

    nextQ.push(from);
    distances[from] = nextDist;
    ++nextDist;

    while (!nextQ.empty())
    {
        currentQ = nextQ;
        nextQ = queue<int>();
        
        while (!currentQ.empty())
        {
            int c = currentQ.back();
            currentQ.pop();

            for (const auto& e : edges[c])
            {
                if (distances[e] == nil)
                {
                    nextQ.push(e);
                    distances[e] = nextDist;
                }
            }
        }
        
        ++nextDist;
    }

    return distances;
}

void solve()
{
    using namespace std;

    int n;
    cin >> n;

    //隣接リスト形式(1オリジン)
    vvi edges(n + 1);

    //読み込み
    for (int i = 1; i <= n; ++i)
    {
        int u, k;
        cin >> u >> k;

        edges[u] = vector<int>(k);

        for (int j = 0; j < k; ++j)
        {
            cin >> edges[u][j];
        }
    }

    auto dist = DistanseFrom(edges, 1);

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

int main()
{
    solve();
    return 0;
}

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

int main()
{
    int n;
    cin >> n;
    int adj[n][n];
    int V[n];
    for (int i = 0; i < n; i++)
    {
        int u, k;
        cin >> u >> k;
        V[i] = k;
        for (int j = 0; j < k; j++)
        {
            int v;
            cin >> v;
            adj[u - 1][j] = v - 1;
        }
    }
    queue<int> q;
    int d[n];
    for (int i = 0; i < n; i++)
        d[i] = -1;
    d[0] = 0;
    q.push(0);
    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        for (int i = 0; i < V[u]; i++)
        {
            int v = adj[u][i];
            if (d[v] == -1)
            {
                d[v] = d[u] + 1;
                q.push(v);
            }
        }
    }

    for (int i = 0; i < n; i++)
        cout << i + 1 << ' ' << d[i] << endl;
}

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

class Vertex {
public:
    int num;
    bool flag;                  // 以前訪れたかどうか
    vector<int> adj;            // 隣接リスト
};

int dist[101];
void bfs(map<int, Vertex>& graph, Vertex s) {
    queue<Vertex> que;

    dist[s.num] = 0;
    graph[s.num].flag = true;
    que.push(s);
    while (!que.empty()) {
        Vertex u = que.front(); que.pop();
        for (auto i = 0; i < u.adj.size(); i++) {
            Vertex v = graph[u.adj[i]];
            if (!v.flag) {
                graph[u.adj[i]].flag = true;
                dist[v.num] = dist[u.num]+1;
                que.push(v);
            }
        }
    }
}

int main(void) {
    int n;
    cin >> n;
    for (int i = 0; i < 101; i++) {
        dist[i] = -1;
    }

    map<int, Vertex> graph; // 頂点の番号->頂点
    for (int i = 0; i < n; i++) {
        Vertex v;
        int num, k;
        cin >> num >> k;
        v.flag = false;
        v.num = num;
        for (int j = 0; j < k; j++) {
            int tmp;
            cin >> tmp;
            v.adj.push_back(tmp);
        }
        graph[num] = v;
    }

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

    return 0;
}

C++: #include <stdio.h>
#include <string.h>
#include<iostream>
#include<queue>
using namespace std;

char s[13][1];
int D[106][106];
int A[106],f[106],w,h,n,sx,sy,gx,gy,e,g[106];
int   kensa(int ,int);
int main(){
	queue<int> P;
	int i,j,a,b,c,d;
	for(i=1;i<=100;i++){
		for(j=1;j<=100;j++){
			D[i][j]=-1;		
		}					
	}						
	for(i=0;i<105;i++){		
		A[i]=0;				
		f[i]=-1;
		g[i]=0;
	}							
	scanf("%d" ,&a);//     a=4
	for(i=1;i<=a;i++){
        scanf("%d",&b);		//
		scanf("%d",&b);			//b=2					//
		for(j=1;j<=b;j++){		//
		scanf("%d",&c);			//					//
		D[i][c]=1;
//
		}						//D[???][???]
	}				
	for(i=1;i<=a;i++){
		for(j=1;j<=a;j++){
	//		printf("%d %d %d\n",i,j,D[i][j]);
		}	
	}//
	P.push(1);
	//P???1
	f[1]=0;
	while(!P.empty()){			//
		d=P.front();
		//
		A[d]=1;
		//
		P.pop();				//
		for(i=1;i<=a;i++){
			//printf("%d %d %d\n",d,i,D[d][i]);//
			if(D[d][i]==-1){		//
			continue;			//
			}					//
			if(A[i]==1){		//
			continue;			//
			}					//
			P.push(i);			//
			
			g[i]=g[d]+1;
			A[i]=1;
			//printf("%d\n",P.back());
		}	
	}							//
	for(i=1;i<=a;i++){			//
	printf("%d %d\n",i, g[i]);	//
	}
	return 0;
}