Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

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

const long N = 100;
const long WHITE = 0;
const long GRAY = 1;
const long BLACK = 2;

long n, M[N + 1][N + 1];
long color[N + 1], d[N + 1], f[N + 1], tt;
long nt[N + 1];

long next(long u){
	for (long v = nt[u]; v <= n; v++){
		nt[u] = v + 1;
		if (M[u][v]) return v;
	}
	return -1;
}

void dfs_visit(long r){
	for (long i = 1; i <= n; i++) nt[i] = 1;

	stack<long> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = ++tt;

	while (!S.empty()){
		long u = S.top();
		long v = next(u);
		if (v != -1){
			if (color[v] == WHITE){
				color[v] = GRAY;
				d[v] = ++tt;
				S.push(v);
			}
		}
		else {
			S.pop();
			color[u] = BLACK;
			f[u] = ++tt;
		}
	}
}

void dfs(){
	for (long i = 1; i <= n; i++){
		color[i] = WHITE;
		nt[i] = 1;
	}
	tt = 0;

	for (long u = 1; u <= n; u++){
		if (color[u] == WHITE) dfs_visit(u);
	}
	for (long i = 1; i <= n; i++){
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
}

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

	for (long i = 1; i <= n; i++){
		cin >> u >> k;
		for (long j = 1; j <= k; j++){
			cin >> v;
			M[u][v] = 1;
		}
	}

	dfs();

	return 0;
}

C++: #include <iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
typedef int long long ll;

using namespace std;
static const int WHITE =0;
static const int GRAY=1;
static const int BLACK=2;
static const int N=100;

int n,color[N],tt,d[N],f[N];
int M[N][N];
int nt[N];
int next(int u){
    for(int v=nt[u];v<n;v++){
        nt[u]=v+1;//頂点に複数頂点隣接してる場合、小さいのから取り出せるように、
        //nt[u]nextで渡した頂点の数がはいる
        if(M[u][v])return v;
    }
    
    
    return -1;
}



void dfs_visit(int r){
    for(int i=0;i<n;i++){
        nt[i]=0;
    }
    stack<int>S;
    S.push(r);
    color[r]=GRAY;
    d[r]=++tt;
    
    while(!S.empty()){
        int u=S.top();
        int v=next(u);
        if(v!=-1){
            if(color[v]==WHITE){
                color[v]=GRAY;
                d[v]=++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[v]=BLACK;
            f[u]=++tt;
        }
    }
    
}

void dfs(){
    
    rep(i,n){color[i]=WHITE;nt[i]=0;}tt=0;
    
    
    rep(i,n){
        if(color[i]==WHITE){
            dfs_visit(i);
           }
    }
        
        
    rep(i,n){
        
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    
    
    
    
    
}



int main(){
    
    cin>>n;
    rep(i,n){
        int k,l;cin>>k>>l;
        k--;
        for(int j=0;j<l;j++){
            int u;
            cin>>u;
            M[k][u-1]=1;
        }
    }
  /*  rep(i,n){
        rep(j,n){cout<<M[i][j];}
    cout<<endl;
    }*/
    dfs();
    
    
return 0;
}

C++: #include <iostream>
#include <utility>
#include <string>
#include <algorithm>
#include <set>
#include <queue>
#include <vector>
#define MAX 10010
#define rep(i,p) for(int i=0;i<p;i++)
#define pb push_back
using namespace std;
int n,hoge,foo,visit_time=1;
int graph[MAX][MAX] = {0};
int d[MAX]; // ????????????
int f[MAX]; // ??£??\????????????????????????

void dfs (int cur) {
  // visiting cur
  d[cur] = visit_time;
  visit_time++;

  rep(dst,n) {
    if (graph[cur][dst] == 1 && d[dst] == -1) dfs(dst);
  }
  f[cur] = visit_time;
  visit_time++;
}

int main(){
  cin >> n;
  rep(i,n) {
    d[i] = -1;
    f[i] = -1;
  }
  rep(i,n) {
    cin >> hoge >> foo;
    rep(j,foo) {
      cin >> hoge;
      graph[i][hoge-1] = 1;
    }
  }
  dfs(0);
  rep(i,n) cout << i+1 << " " << d[i] << " " << f[i] << endl;
  return 0;
}

C++: #include<bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int n,u,k,v,a[101][101],start[101],end[101],p,f[101];
void dfs(int u){
	if(!f[u]){
    f[u]++;
    start[u]=++p;
    r(i,1,n+1)if(a[u][i])dfs(i);
    end[u]=++p;
  }
}
int main(){
	cin>>n;
	r(i,0,n){
    cin>>u>>k;
		r(i,0,k){
      cin>>v;
			a[u][v]++;
		}
	}
	r(i,1,n+1)if(!f[i])dfs(i);
	r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}