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 <bits/stdc++.h>
#define FOR(i,a,b) for(int i= (a); i<(b); i++)
#define REP(i,n) for(int i=0;i < (n);i++)
#define ALL(obj) (obj).begin(),(obj).end()
using namespace std;

const long long INF = 1LL << 60;
const int MOD = (int)1e9 + 7;
typedef long long ll;
//約数列挙
vector<long long> divisor(long long n) {
    vector<long long> ret;
    for (long long i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            ret.push_back(i);
            if (i * i != n) ret.push_back(n / i);
        }
    }
    //sort(ret.begin(), ret.end()); // 昇順に並べる
    return ret;
}
vector<bool> seen;
vector<int> start_time;vector<int> finish_time;
vector<vector<int> > g;
void dfs(int ind,int& cnt){
    start_time[ind]=++cnt;
    seen[ind]=true;
    for(int nextind : g[ind]){
        if(seen[nextind])continue;
        dfs(nextind,cnt);
    }
    finish_time[ind]=++cnt;
}
signed main () {
    int n;scanf("%d",&n);
    g.resize(n);
    REP(i,n){
        int ind,tmp;scanf("%d %d",&ind,&tmp);
        REP(j,tmp){
            int a;scanf("%d",&a);
            g[i].push_back(a-1);
        }
    }
    seen.assign(n,false);start_time.resize(n);finish_time.resize(n);
    int cnt =0;
    REP(i,n){
        if(seen[i])continue;
        dfs(i,cnt);
    }
    REP(i,n){
        printf("%d %d %d\n",i+1,start_time[i],finish_time[i]);
    }
    return 0;
}

C++: #include <iostream>
#include <set>
#include <vector>
#include <queue>
#include <stack>
#include <utility>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

int g[101][101],n,d[101],f[101];

int main() {
    cin >> n;
    for(int i = 0;i < n;i++) {
        int u,k,v;
        cin >> u >> k;
        for(int j = 0;j < k;j++) {
            cin >> v;
            g[u][v]++;
        }
    }
    stack<int> dfs;
    int time = 2;
    dfs.push(1);
    d[1] = 1;
    while(!dfs.empty()){
        int u = dfs.top();
        bool fl = false;
        for(int i = 1;i <= n;i++){
            if(g[u][i] && d[i] == 0 && u != i) {
                dfs.push(i);
                cout << "push" << i  << "u:" << u<< endl;
                d[i] = time++;
                fl = true;
                break;
            }
        }
        if(!fl) {
            dfs.pop();
            f[u] = time++;
        }
    }
    for(int i = 1;i <=n;i++) {
        cout << i << " " << d[i] << " " << f[i] <<endl;
    }
}

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

typedef long long ll;
#define inf 1e9+7

int f[200],d[200];
bool table[200][200];
int cou;

void init(){
    for(int i=0;i<200;i++){
        f[i]=d[i]=-1;
    }
}

void dfs(int n,int itr){
    cou++;
    if(d[itr]<0)d[itr]=cou;
    for(int i=0;i<n;i++){
        if(d[i]<0&&table[itr][i]) dfs(n,i);
    }
    cou++;
    f[itr] = cou;
}

void solve(int n){
    for(int i=0;i<n;i++){
        if(d[i]<0)dfs(n,i);
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);


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

    solve(n);

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

    return 0;
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int arisutoteresu[200][200] = {0};
int imap[200][200] = {0};
int n,u[200],k[200];
int GetIt[200]={0};
int FinIt[200]={0};
bool used[200];
int fincou=1;
int Gcounter;
int Fcounter;
int Find;
void dfs(int where){
  fincou++;
  Fcounter++;

  GetIt[where]=Find;
 
  if(k[where] != 0){
    for(int i=0;i<k[where];i++){
      if(!used[imap[where][i]]){
	Gcounter++;
	Find++;

	used[imap[where][i]] = true;
	dfs(imap[where][i]);
	fincou++;
	Fcounter++;

      }
    }
  }
    FinIt[where] = fincou;
     
}
 
int main(){
  
  int ad;
   
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    cin >> u[i];
    cin >> k[u[i]];
    for(int j=0;j<k[u[i]];j++){
      cin >> ad;
      imap[u[i]][j] = ad;
    }
  }
 
 
  for(int j=0;j<200;j++)used[j] = false;
  Gcounter=Fcounter=1;
 
  Find = 1;
  int Index=0;
  bool fin = true;
  
    for(int i=0;i<n;i++){
      if(!used[u[i]]){//cout << "not used" << u[i] << endl;
	//used[u[i]]=true;
      dfs(u[i]);
      Find = fincou+1;
      fincou++;      
    
      }
    }
  
  //dfs(u[0]);   

   
  
  //cout << "counter - " << Find << ", F" << fincou << endl;
  for(int i=0;i<n;i++){
    cout << i+1 << " " << GetIt[i+1]  << " " << FinIt[i+1];
    cout << endl;
  }
 
  return 0;
}