Go: package main

import (
	"fmt"
	"os"
	"bufio"
	"strconv"
	"container/list"
)

const MaxNode int = 100

var d []int
var A [][]int
var N int
var l *list.List

func bfs(u int) {
	d[u] = 0
	l.PushBack(u)
	for ;l.Len() != 0; {
		u = l.Front().Value.(int)
		l.Remove(l.Front())
		for v:=0; v<N; v++ {
			if A[u][v] == 0 {
				continue
			}
			if d[v] != -1 {
				continue
			}
			d[v] = d[u] + 1
			l.PushBack(v)
		}
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func print() {
	for i:=0; i<N; i++ {
		fmt.Printf("%d %d\n", i+1, d[i])
	}
}

func initVariable() {
	d = make([]int, MaxNode)
	A = make([][]int, MaxNode)
	l = list.New()
	for i:=0; i<MaxNode; i++ {
		A[i] = make([]int, MaxNode)
		d[i] = -1
	}
}


func main() {
	initVariable()
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	for i:=0; i<N; i++ {
		idx := nextInt(scanner)
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			node := nextInt(scanner)
			A[idx-1][node-1] = 1 
		}
	}
	bfs(0)
	print()
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <string.h>

/*
 * ref. http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_B
 */

using namespace std;

const int MAX_N = 100;

int n;
vector<int> adjlist[MAX_N];
int d[MAX_N];
queue<int> que;

void bfs() {
    int id = 1;

    d[id - 1] = 0;
    // for (int i = 0; i < (int) adjlist[id - 1].size(); i++) {
    //     int next_id = adjlist[id - 1][i];
    //     if (d[next_id - 1] < 0 || d[next_id - 1] > d[id - 1] + 1) {
    //         d[next_id - 1] = d[id - 1] + 1;
    //         que.push(next_id);
    //     }
    // }
    que.push(id);

    while (!que.empty()) {
        id = que.front();
        que.pop();

        for (int i = 0; i < (int) adjlist[id - 1].size(); i++) {
            int next_id = adjlist[id - 1][i];
            if (d[next_id - 1] < 0 || d[next_id - 1] > d[id - 1] + 1) {
                d[next_id - 1] = d[id - 1] + 1;
                que.push(next_id);
            }
        }
    }
}

int main(void) {
    cin >> n;

    for (int i = 0; i < n; i++) {
        int id, m;
        cin >> id >> m;
        for (int j = 0; j < m; j++) {
            int x;
            cin >> x;
            adjlist[id - 1].push_back(x);
        }
    }

    memset(d, -1, sizeof(d));
    bfs();

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

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
const int MOD =1e9+7;
using ll=long long;
using Graph = vector<vector<int>>;

int main() {
    int n; 
    cin >> n;
    Graph G(n);
    
    rep(i,n){
        int N; cin >> N; N--;
        int k; cin >> k;
        rep(j,k){
            int v; cin >> v; v--;
            G[N].push_back(v);
        } 
    }

    vector<int> dist(n, -1);
    queue<int> que;
    dist[0] = 0;
    que.push(0);

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

        for(int nv :G[v]){
            if(dist[nv] != -1) continue;

            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }
    rep(i,n){
        cout << i+1 <<" "<< dist[i] << endl;
    }
}

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

using namespace std;

#define N 100
#define INF -1

int n,d[N],m[N][N];

void bfs(int s){
	for(int i=0;i<n;i++){
		d[i] = INF;
	}
	int u,v;
	queue<int> q;
	q.push(s);
	d[s] = 0;
	while( !q.empty() ){
		u = q.front();
		q.pop();
		for(v=0;v<n;v++){
			if(d[v] != INF || m[u][v] != 1)continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	for(int i=0;i<n;i++){
		printf("%d %d\n",i+1,d[i]);
	}
}

int main(void){
	int u,k,v;
	for(int i=0;i<N;i++){
		for(int j=0;j<N;j++){
			m[i][j] = 0;
		}
	}
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		scanf("%d %d",&u,&k);
		u--;
		for(int j=0;j<k;j++){
			scanf("%d",&v);
			v--;
			m[u][v] = 1;	
		}
	}
	bfs(0);
	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <stack>
#include <cstdlib>
#include <queue>
#include <vector>
#include <set>

using namespace std;
int n,m,l,p;
bool a[100][100];
int D[100];
void  bfs ( int src) {
	queue<int> Q;
	Q.push(src);
	D[src]=0;
	while( ! Q.empty() ) {
		int cur = Q.front();
		Q.pop();
		for(int dst = 0; dst < n; dst++ ) {
			if( D[dst] == 0 && a[cur][dst] == 1 ) {
				D[dst] = D[cur] + 1;
				Q.push(dst);
			}
		}
	}
	for (int i = 0; i < n;i++) {
	cerr << i+1 <<  " " << D[i] <<  endl;
	}
}
int main() {
	cin >> 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++){
		cin >> m;
		cin >> l;
		for(int j = 0; j < l;j++) {
			cin >> p;
			a[m-1][p-1] = 1;
		}
	}
	bfs(0);
}

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

using namespace std;

int d[100];
vector<int> adj[100];

void bfs(int n, int start) {
	queue<int> que;

	for (int i = 0; i < n; i++)
		d[i] = i == start ? 0 : -1;

	que.push(start);
	while(!que.empty()) {
		int from = que.front();
		que.pop();

		for (int& to : adj[from])
			if (d[to] == -1) {
				d[to] = d[from] + 1;
				que.push(to);
			}
	}
}

int main() {
	int n;

	cin >> n;

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		while (k--) {
			int v;
			cin >> v;
			adj[u - 1].push_back(v - 1);
		}
	}

	bfs(n, 0);

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

	return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <list>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#define rep(i, n) for (int i = 0; i < n; i++)

using namespace std;

const int INF = 1 << 30;
const int MOD = 1000000007;
const int MAX = 100000;
const int N = 100;

vector<int> G[N];
int d[N];

int main() {
	int n; cin >> n;
	rep(i, n) {
		int _, n2; cin >> _ >> n2;
		rep(j, n2) {
			int k; cin >> k; k--;
			G[i].push_back(k);
		}
	}
	rep(i, n) d[i] = -1;

	queue<int> Q;
	Q.push(0);
	d[0] = 0;
	while (!Q.empty()) {
		int i = Q.front(); Q.pop();
		for (auto j : G[i]) {
			if (d[j] != -1) continue;
			d[j] = d[i] + 1;
			Q.push(j);
		}
	}
	rep(i, n) cout << i+1 << ' ' << d[i] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
// Welcome to my source code!

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

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) ? (-1) : d[i]) << endl;
    }
}

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