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) {
			if !dl.isVisited(v) {
				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 <queue>
using namespace std;
queue<int> qu;
int v[101][101];
int dis[101], n;
int d = 0;
int tf;
inline void b1(int t) {
	for (int i = 1; i <= n; i++) {
		if (v[t][i]) {
			tf = 1;
			qu.push(i);
			dis[i] = d + 1;
			for (int j = 1; j <= n; j++)
				v[j][i] = 0;
		}
	}
}
inline void b2() {
	tf = 0;
	for (int i = 1; i <= n; i++)
		if (dis[i] == d) {
			b1(i);
			qu.pop();
		}
	d++;
}
inline void bfs() {
	tf = 1;
	b1(1);
	d++;
	qu.pop();
	while (tf) {
		b2();
	}
}
int main() {
	int u, k, s;
	cin >> n;
	for (int i = 2; i <= n; i++) {
		dis[i] = -1;
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			v[i][j] = 0;
		}
	}
	for (int i = 0; i < n; i++) {
		cin >> u;
		cin >> k;
		for (int j = 0; j < k; j++) {
			cin >> s;
			v[u][s] = 1;
		}
	}
	qu.push(1);
	for (int i = 1; i <= n; i++)
		v[i][1] = 0;
	bfs();
	for (int i = 1; i <= n; i++) {
		cout << i << " " << dis[i] << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<stdio.h>
#include<cstring>
#include<math.h>
#include<map>
#include<bitset>
#include<iomanip>
#include<queue>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
int n;
vector<int> a[100];
int dist[100];
const int INF = 100000000;

int main() {
  cin >> n;
  rep(i, n) {
    int x, y;
    cin >> x >> y;
    rep(i, y) {
      int z;
      cin >> z;
      a[x-1].push_back(z-1);
    }
  }

    rep(i, n) {
      dist[i] = INF;
    }
    dist[0] = 0;

    queue<int> que;

    que.push(0);
    while(que.size()) {
      int p = que.front();
      que.pop();

      for(int i = 0; i < a[p].size(); i++) {
        if(dist[a[p][i]] > dist[p] + 1) {
          dist[a[p][i]] = dist[p] + 1;
          que.push(a[p][i]);
        }
      }
    }

  rep(i, n) {
    if(dist[i] != INF) cout << i + 1 << " " << dist[i] << endl;
    else cout << i + 1 << " " << -1 << endl;
  }
    

  return 0;
}

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

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

int n, M[N][N];
int d[N]; // 距離で訪問状態を管理する

void bfs(int s) {
	queue<int> q;
	q.push(s);
	for (int i = 0; i < n; i++) d[i] = INF;
	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] != INF) continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}

	for (int i = 0; i < n; i++) {
		cout << i + 1 << " " << ((d[i] == INF) ? (-1) : d[i]) << 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--; // 0オリジン
		for (int j = 0; j < k; j++) {
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}

	bfs(0);
	
	return 0;
}

C++: #include <stdio.h>
#include <vector>
#include <queue>
using namespace std;
int main() {
    int V, k, source, target, current, next;
    bool oneVisited;
    scanf("%d", &V);
    vector<int> G[V+1];
    bool visited[V+1];
    int disc[V+1];
    fill(visited, visited+V+1, 0);
    fill(disc, disc+V+1, -1);
    for (int i = 0; i < V; i++) {
        scanf("%d %d", &source, &k);
        for (int j = 0; j < k; j++) {
            scanf("%d", &target);
            G[source].push_back(target);
        }
    }
    queue<int> q;
    q.push(1);
    int d = 0; disc[1] = 0;
    visited[1] = true;
    while (!q.empty()) {
        current = q.front(); q.pop();
        for (int i = 0; i < G[current].size(); i++) {
            next = G[current][i];
            if (!visited[next]) {
                visited[next] = true;
                disc[next] = disc[current]+1;
                q.push(next);
            }
        }
    }
    for (int i = 1; i <= V; i++) printf("%d %d\n", i, disc[i]);
    return 0;
}

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

#define M 1000000007
vector<int> dist;
vector<vector<int>> edge;

int main() {
    int n;
    cin >> n;
    dist.resize(n, M);
    edge.resize(n);
    for (int i = 0; i < n; ++i) {
        int id, k;
        cin >> id >> k;
        if (id != i + 1) exit(1);
        if (!k) continue;

        edge[i].resize(k);
        for (int j = 0; j < k; ++j) {
            cin >> edge[i][j];
            --edge[i][j];
        }
    }
    queue<int> q;
    q.push(0);
    dist[0] = 0;
    while (!q.empty()) {
        int p = q.front();
        q.pop();
        for (int t : edge[p]) {
            if (dist[t] > dist[p] + 1) {
                dist[t] = dist[p] + 1;
                q.push(t);
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << (i + 1) << " " << (dist[i] < M ? dist[i] : -1) << "\n";
    }
    return 0;
}