Go: package main

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

type AdjacentList struct {
	matrix [][]int
}

func NewEmptyAdjacentList(dim int) *AdjacentList {
	matrix := make([][]int, dim)
	for i := 0; i < dim; i++ {
		matrix[i] = make([]int, dim)
	}
	return &AdjacentList{matrix: matrix}
}

func (al *AdjacentList) set(node int, adjacent int) {
	al.matrix[node-1][adjacent-1] = 1
}

func (al *AdjacentList) findAdjacentsFor(node int) []int {
	adjacents := []int{}
	for i, v := range al.matrix[node-1] {
		if v == 1 {
			adjacents = append(adjacents, i+1)
		}
	}
	return adjacents
}

type DistanceList struct {
	list []int
}

func NewDistanceList(dim int) *DistanceList {
	list := make([]int, dim)
	for i := 0; i < dim; i++ {
		list[i] = -1
	}
	return &DistanceList{list: list}
}

func (dl *DistanceList) set(node int, distance int) {
	dl.list[node-1] = distance
}

func (dl *DistanceList) get(node int) int {
	return dl.list[node-1]
}

func (dl *DistanceList) isVisited(node int) bool {
	return dl.list[node-1] >= 0
}

type Position struct {
	node     int
	distance int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	dim, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	al := NewEmptyAdjacentList(dim)

	for i := 1; i <= dim; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}

		adjacentNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		for j := 0; j < adjacentNum; j++ {
			adjacent, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			al.set(node, adjacent)
		}
	}

	dl := NewDistanceList(dim)

	bfs(al, dl)

	for i := 1; i <= dim; i++ {
		fmt.Printf("%d %d\n", i, dl.get(i))
	}
}

func bfs(al *AdjacentList, dl *DistanceList) {
	stack := []Position{Position{node: 1, distance: 0}}
	for len(stack) > 0 {
		currentPosition := stack[0]
		stack = stack[1:]
		if !dl.isVisited(currentPosition.node) {
			dl.set(currentPosition.node, currentPosition.distance)
		}
		for _, v := range al.findAdjacentsFor(currentPosition.node) {
			stack = append(stack, Position{node: v, distance: currentPosition.distance + 1})
		}
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <deque>
using namespace std;
 
struct status{
    int idx_node;
    vector<int> children;
    int visited = 0;
    int depth = 0;
};
 
deque<int> schedule; 
vector<status> graph;

int depth = 1;
void bfs(){
    if (schedule.size()>1){
        
        int now_node = schedule.front();
        schedule.pop_front();
        
        switch(now_node){
            case 0: {
                ++depth;
                schedule.push_back(0);
                break;
            }
            default: {
                for(auto& next_node:graph[now_node-1].children){
                    if(graph[next_node-1].visited) continue;
                    
                    graph[next_node-1].visited = 1;
                    graph[next_node-1].depth = depth;  
                    schedule.push_back(next_node);
                }
            }
        }
        bfs();
    }
}
 

int main(void){cin.tie(0);ios::sync_with_stdio(false);
 
    //stdi
    int nb_nodes; cin >> nb_nodes;
    graph.resize(nb_nodes);
    for(auto& times:graph){
        int idx_node; cin >> idx_node; graph[idx_node-1].idx_node = idx_node;
        int nb_edges; cin >> nb_edges; graph[idx_node-1].children.resize(nb_edges);
        for(auto& a:graph[idx_node-1].children){
            cin >> a;
        }
        sort(graph[idx_node-1].children.begin(),graph[idx_node-1].children.end());
    }
    
    //bfs
    schedule.push_back(1);
    schedule.push_back(0);
    bfs();
     
    //stdo
    for(auto& a:graph){
        cout<<a.idx_node<<" "
            <<a.depth<<"\n";
    }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <queue>
#include <iomanip>
#define REP(i, n) for(int i = 0; i < n; i++)
#define REPR(i, n) for(int i = n; i >= 0; i--)
#define FOR(i, m, n) for(int i = m; i < n; i++)
#define INF 100000
#define ALL(v) v.begin(), v.end()
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
vector<vector< int> > G;
int N;
vector<int> flag;
vector<int> d;
queue<int> que;

void bfs(int k){
    if(flag[k] == -1){
        que.push(k);
        flag[k] = 0;
        while(!que.empty()){
            int now = que.front(); que.pop();
            if(G[now].size() != 0){
                REP(i,G[now].size()){
                    if(flag[G[now][i]] == -1){
                        flag[G[now][i]] = flag[now] + 1;
                        que.push(G[now][i]);
                    }
                }
            }
        }
    }
}

int main(){
    int n;
    int time = 0;

    
    cin >> n;
    G.resize(n);
    d.resize(n);//最初に発見された時刻
    flag.resize(n,-1);
    REP(i,n){
        int u,k; cin >>u>>k;
        u--;
        if(k != 0){
        REP(j,k){
            int a; cin >>a;
            G[u].push_back(a);
            G[u][j]--;
        }
        }
    }
    //time = 0;
    bfs(0);

    REP(i,n){
        cout << i + 1 << " " << flag[i] << endl;
    }
}