Go: package main

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

var distance []int

type queue struct {
	q    []int
	head int
	tail int
}

func (q *queue) push(n int) {
	q.q[q.tail] = n
	q.tail++
}

func (q *queue) pop() int {
	q.head++
	return q.q[q.head-1]
}

func (q *queue) isEmpty() bool {
	return q.head == q.tail
}

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func bfs(graph [][]int, s int) {
	distance = make([]int, len(graph))

	infty := -1
	for i := 0; i < len(distance); i++ {
		distance[i] = infty
	}
	distance[s] = 0

	q := &queue{make([]int, 1000), 0, 0}
	q.push(s)

	for !q.isEmpty() {
		u := q.pop()
		for i := 0; i < len(graph); i++ {
			if graph[u][i] == 0 {
				continue // u, i間に辺がない場合
			}
			if distance[i] != infty {
				continue // 訪問済みの場合
			}
			// 訪問するnodeの始点からの距離を設定し、訪問キューに入れる
			distance[i] = distance[u] + 1
			q.push(i)
		}
	}

	// print distance
	for i, d := range distance {
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	adj := makeAdjList()
	bfs(adj, 0)
}

C++: #include<iostream>
#include<queue>
using namespace std;
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++){
    for(int j=0;j<n;j++) M[i][j] = 0;
  }

  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);

  return 0;
}

C++: #include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>
#include <queue>

using namespace std;
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++){
        for(int j=0;i<n;j++) M[i][j]=0;
    }

    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);
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <string>
#include <algorithm>
#include <utility>
#include <climits>
#include <cstring>
#include <cstdio>

using namespace std;
typedef long long int llg;

const int INF = 1000001000;
#define REP(var, count) for(int var=0; var<count; var++)


int vert[100010];
int edge[500010][3];

int main(void) {
	int V, E, r;
	scanf("%d", &V);
	scanf("%d", &E);
	scanf("%d", &r);
	
	REP(v, V) { vert[v] = INF; }
	vert[r] = 0;
	
	REP(i, E) {
		scanf("%d", &edge[i][0]);
		scanf("%d", &edge[i][1]);
		scanf("%d", &edge[i][2]);
	}
	
	REP(v, V) {
		bool update = false;
		REP(i, E) {
			int s = edge[i][0];
			int t = edge[i][1];
			if ( vert[s] != INF && vert[t] > (vert[s]+edge[i][2]) ) {
				vert[t] = vert[s] + edge[i][2];
				update = true;
			}
		}
		if ( !update ) { break; }
	}
	
	REP(v, V) {
		if ( vert[v] == INF ) {
			cout << "INF" << endl;
		} else {
			cout << vert[v] << endl;
		}
	}

}

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

using namespace std;

enum COLOR {
  WHITE,
  GRAY,
  BLACK,
};

static const int INFTY = INT_MAX;
static const int N = 100;

static int M[N][N] = {};
static vector<COLOR> color(N, WHITE);
static vector<int> d(N, INFTY);

static void bfs(int n, int s) {
  color[s] = GRAY;
  d[s] = 0;

  queue<int> Q;
  Q.push(s);

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

int main() {
  int n;
  cin >> n;

  int number, count, value;
  for (int i = 0; i < n; i++) {
    cin >> number >> count;
    number--;
    for (int j = 0; j < count; j++) {
     cin >> value;
     value--;
     M[number][value] = 1; 
    }
  }
  
  bfs(n, 0);
  
  for (int i = 0; i < n; i++) {
    cout << i + 1 << " " << ((d[i] == INFTY) ? -1 : d[i]) << endl; 
  }

  return 0;
}

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

int main(){
  vector<int> G[100];
  queue<int> q;
  vector<int> d(100,-1);
  int n,u,k,v,depth;
  bool flg;
  
  cin >> n;
  for (int i=0;i<n;i++){
    cin >> u>> k;
    for (int j=0;j<k;j++){
      cin >> v;
      G[u-1].push_back(v-1);
    }
  }
  depth=0;
  q.push(0);
  d[0]=depth;
  while (!q.empty()){
    u=q.front();
    for (int i=0;i<G[u].size();i++){
      v=G[u][i];
      if (d[v]==-1){
	q.push(v);
	d[v]=d[u]+1;
	flg=true;
	break;
      }
    }
    if (!flg){
      q.pop();
    }else{
      flg=false;
    }
  }
    
  for (int i=0;i<n;i++)
    cout << i+1 <<" "<< d[i]<<endl;
  
  return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>
#include <limits.h>
using namespace std;
vector<int> v[101];
int d[101];
queue<int> q;
bool flag[101];
int main(){
	int n, u, k; scanf("%d", &n);
	for (int i = 0; i < n; ++i){
		scanf("%d %d", &u, &k);
		for (int j = 0; j < k; ++j){
			int tmp; scanf("%d", &tmp);
			v[u].push_back(tmp);
		}
	}
	memset(d, -1, sizeof(d));
	d[1] = 0;
	q.push(1); flag[1] = true;
	while (!q.empty()){
		int m = q.front(); q.pop();
		for (int i = 0; i < v[m].size(); ++i){
			int tmp = v[m][i];
			if (!flag[tmp]){
				flag[tmp] = true;
				d[tmp]=d[m]+1;
				q.push(tmp);
			}
		}
	}
	for (int i = 1; i <= n; ++i){
		cout << i << ' ' << d[i] << '\n';
	}
}

C++: #include <bits/stdc++.h>
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;
template<class T>inline bool chmax(T &a, const T &b){if(a < b){a = b; return 1;}return 0;}
template<class T>inline bool chmin(T &a, const T &b){if(a > b){a = b; return 1;}return 0;}
typedef long long ll;

int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n; cin >> n;
  vector<vector<int> > E(n, vector<int>());
  REP(i, n){
    int u, k; cin >> u >> k; u--;
    REP(j, k){
      int v; cin >> v; v--;
      E[u].push_back(v);
    }
  }
  vector<int> d(n, -1);
  vector<bool> dd(n, false);
  d[0] = 0;
  dd[0] = true;
  queue<int> q;
  q.push(0);
  while(!q.empty()){
    int cur = q.front(); q.pop();
    for(auto &i : E[cur]){
      if(dd[i]) continue;
      d[i] = d[cur] + 1;
      q.push(i);
      dd[i] = true;
    }
  }
  REP(i, n){
    cout << i+1 << " " << d[i] << endl;
  }
}