Go: package main

/*
深さ優先探索
*/

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

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

C++: #include<bits/stdc++.h>
using namespace std;
int n,M[101][101];
int visit[101],d[101],f[101],t;
const int WHITE=0;
const int GLAY=1;
const int BLACK=2;

void dfs(int u){
  visit[u]=GLAY;
  d[u]=++t;
  for(int v=0;v<n;v++){
    if(M[u][v]==0) continue;
    if(visit[v]==WHITE){
    dfs(v);
    }
  }
  visit[u]=BLACK;
  f[u]=++t;
}



int main(){
  int u,v,k;
  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;
    }
  }

 
 
  for(int i=0;i<n;i++){
    if(visit[i]==WHITE){
      dfs(i);
    }
  }
  for(int i=0;i<n;i++){
    cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
  }

  
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n - 1); i >= 0; i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) int(x.size())
#define get_unique(x) x.erase(unique(all(x)), x.end());
typedef long long ll;
typedef complex<double> Complex;
const int INF = 1e9;
const ll MOD = 1e9 + 7;
const ll LINF = 1e18;
template <class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
bool chmin(T& a, const T& b) {
    if (b < a) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
vector<T> make_vec(size_t a) {
    return vector<T>(a);
}
template <class T, class... Ts>
auto make_vec(size_t a, Ts... ts) {
    return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}
vector<int> d, f;
vector<vector<int>> g;
void dfs(int now, int &time) {
    d[now] = time;
    time++;
    for (int nxt : g[now]) {
        if (d[nxt] != -1) continue;
        dfs(nxt, time);
    }
    f[now] = time;
    time++;
}
int main() {
    int n;
    cin >> n;
    g.resize(n);
    d.assign(n, -1);
    f.resize(n);
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        rep(j, k) {
            int v;
            cin >> v;
            v--;
            g[i].push_back(v);
        }
    }
    int time = 1;
    rep(i,n) {
        if(d[i]==-1) dfs(i,time);
    }
    rep(i,n) {
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}

C++: #include<iostream>
#include<cstdio>
#include<stack>
#include<algorithm>
#include<cstring>
#define white 0
#define balck -1
#define grey 1
using namespace std;

int a[110][110],n;
int color[110];
int t=0;
int ts[105],te[105];

void dfsinit()
{
    for(int i=1;i<=100;i++)
        color[i]=white;
}

void dfsvisit(int u)
{
    color[u]=grey;
    ts[u]=++t;  //搜索
    for(int j=1;j<=n;j++)  //搜索?点
    {
        if(color[j]==white && a[u][j]==1)
        {
           dfsvisit(j);  //深搜
        }
    }
    te[u]=++t;
    color[u]=balck;
}

void dfs()
{
    dfsinit();
    for(int i=1;i<=n;i++)
    {
        if(color[i]==white)
            dfsvisit(i);
    }
}

int main()
{
   int key,d,x;
   t=0;
   memset(a,0,sizeof(a));
   scanf("%d",&n);
   for(int i=1;i<=n;i++)
   {
       scanf("%d%d",&key,&d);
       for(int j=1;j<=d;j++)
       {
        scanf("%d",&x);
        a[key][x]=1;
       }
   }

   dfs();
   for(int i=1;i<=n;i++)
   {
       printf("%d %d %d\n",i,ts[i],te[i]);
   }
   return 0;
}