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<cstdio>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<stack>
#include<vector>
using namespace std;
#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int d[MAX],f[MAX];
int color[MAX];
vector<int> V[MAX];
int tt=0,n=0;
stack<int> S;

void dfs(int x){
  S.push(x);
  d[x]=++tt;
  color[x]=GRAY;
  while(!S.empty()){
    int u=S.top();
    int next=-1;
    for(int i=0;i<V[u].size();i++){
      if(color[V[u][i]]==WHITE){
        next=V[u][i]; break;
      }
    }
    if(next==-1){
      color[u]=BLACK;
      S.pop();
      f[u]=++tt;
      continue;
    }
    color[next]=GRAY;
    S.push(next);
    d[next]=++tt;
  }
}

void begindfs(){
  for(int i=0;i<n;i++){
    if(color[i]==WHITE) dfs(i);
  }
}

int main(){
  int u,v,j;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>u>>v;
    u--;
    for(int k=0;k<v;k++){
      cin>>j;
      j--;
      V[u].push_back(j);
    }
  }
  begindfs();
  for(int i=0;i<n;i++){
    cout<<i+1;
    printf(" %d %d\n",d[i],f[i]);
  }

}

C++: #include <iostream>
#include <stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, M[N][N];
int color[N], d[N], f[N], tt;
int nt[N];

// u?????£??\??????v?????????????????????
int next(int u) {
  for (int v = nt[u]; v < n; v++) {
    nt[u] = v + 1;
    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[u] = BLACK;
      f[u] = ++tt;
    }
  }
}

void dfs() {
  // ?????????
  for (int i = 0; i < N; i++) {
    color[i] = WHITE;
    nt[i] = 0;
  }
  tt = 0;

  // ????¨???????u????§??????¨????????±???????????¢?´¢
  for (int u = 0; u < n; u++) {
    if (color[u] == WHITE) dfs_visit(u);
  }
  for (int i = 0; i < n; i++) {
    cout << i + 1 << " " << d[i] << " " << f[i] << endl;
  }
}

int main() {
  int u, k, v, i, j;

  cin >> n;
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) M[i][j] = 0;
  }

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

  dfs();

  return 0;
}

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

C++: #include<iostream>
using namespace std;
int visit[101],d[101],f[101],t;
int n,M[101][101];
static const int WHITE=0;
static const int GRAY=1;

void dfs(int u){
  visit[u]=GRAY;
  d[u]=++t;
  for(int v=0;v<n;v++){
    if(M[u][v]==0) continue;
    if(visit[v]==WHITE) dfs(v);
  }
  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 MAX 105

int main(void) {
	int d[MAX], f[MAX];
	int n, u, k, v, i, j;
	vector<vector<int> > vec;
	vector<int> ve;
	vec.push_back(ve);
	cin >> n;
	for (i = 1; i <= n; i++) {
		ve.clear();
		d[i] = f[i] = 0;
		cin >> u >> k;
		ve.push_back(k);
		while (k--) {
			cin >> v;
			ve.push_back(v);
		}
		vec.push_back(ve);
	}
	stack<int> S_v, S_c;
	int Mytime = 1;
	int now, cnt;
	bool flag;
	for (i = 1; i <= n; i++) {
		if (d[i] != 0) continue;
		S_v.push(i);
		S_c.push(1);
		while (!S_v.empty()) {
			now = S_v.top();
			cnt = S_c.top();
			S_c.pop();
			flag = false;
			if (d[now] == 0) {
				d[now] = Mytime;
				Mytime++;
			}
			while(cnt <= vec[now][0]) {
				if (d[vec[now][cnt]] == 0) {
					flag = true;
					break;
				}
				cnt++;
			}
			if (flag) {
				S_v.push(vec[now][cnt]);
				S_c.push(cnt + 1);
				S_c.push(1);
				continue;
			}
			f[now] = Mytime;
			Mytime++;
			S_v.pop();
		}
	}
	for (i = 1; i <= n; i++) {
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
}