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+1)
	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 <algorithm>
#include <vector>
#include <stack>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <string>
#include <cstdio>
#include <queue>
#include <list>
using namespace std;

int n;

struct Node{
public:
  int id, d, f, flag;
  vector<int> c;
  Node(){d = 1000000007;f = flag = 0;}
};

vector<Node> v(101);

void rec(int id, int &t){
  if(v[id].flag)return;
  else          v[id].flag = 1;
  v[id].d = min(v[id].d, ++t);
  for(int i=0;i<v[id].c.size();i++) {
    rec(v[id].c[i], t);
  }
  v[id].f = max(v[id].f, ++t);
}


bool asc(const Node &right, const Node &left){return right.id < left.id;}

int main(){
  cin >> n;
  
  v[0].id = 0;  
  for(int i=1;i<=n;i++){
    int t, a;  cin >> a >> t;
    vector<int> b(t);
    for(int j=0;j<t;j++){
      int val;cin >> val;
      b[j] = val;
    }
    v[a].id = a;
    v[a].c = b;
  }
  sort(v.begin(), v.end(), asc);

  int ti = 0;
  for(int i=1;i<=n;i++){
    rec(i, ti);
  }

  for(int i=1;i<=n;i++){
    printf("%d %d %d", v[i].id, v[i].d, v[i].f);
    if(i != n)printf("\n");
  }
  return 0;
}

C++: #include<iostream>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

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

void dfs_visit(int u){
    int v;
    color[u]=GRAY;
    d[u]=++tt;
 
    for(v=0; v<n; v++){
        if(M[u][v]==0){continue;}
        if(color[v]==WHITE){dfs_visit(v);}
    }
    color[u]=BLACK;
    f[u]=++tt;
}

void dfs(){
    int u;
 
    for(u=0; u<n; u++){
        color[u]=WHITE;
    }
    tt=0;
    for(u=0; u<n; u++){
        if(color[u]==WHITE){dfs_visit(u);}
    }
    for(u=0; u<n; u++){
        printf("%d %d %d\n",u+1,d[u],f[u]);
    }
}

int main(){
    int i,j,k,u,v;
    scanf("%d",&n);
    for(i=0; i<n; i++){
        for(j=0; j<n; j++){
            M[i][j]=0;
        }
    }

    for(i=0; i<n; i++){
        scanf("%d %d",&u,&k);
        u--;
        for(j=0; j<k; j++){
            scanf("%d",&v);
            v--;
            M[u][v]=1;
        }
    }

    dfs();
    return 0;
}

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

int n,v,u,k,Time,data[101][101],d[101],f[101];

//dfs
void visit(int u){
  int v;
  d[u] = Time++;
 
  for(v = 1; v <= n; v++){
    if(data[u][v]&d[v]==0)
      visit(v);
  }
  f[u] = Time++;
}
 
int main(){
  cin >> n;
  
  //初期化
  Time = 1;
  for(int i = 1; i <= n; i++){
    for(int j = 1; j <= n; j++){
      data[i][j]=0;
      d[j]=0;
      f[j]=0;
    }
  }
  
  //入力
  for(int i = 0; i < n; i++){
    cin >> u >> k;
    for(int j = 0; j < k; j++){
      cin >> v;
      data[u][v]=1;
    }
  }
  
  //dfs
  for(int i = 1;i <= n; i++){
    if(d[i]==0)visit(i);
  }
  
  //出力
  for(int i = 1;i <= n; i++){
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
  
  return 0;
}

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

#define MAX 100
#define FND -1
#define CMP -2

int n, G_list[MAX+1];
int G[MAX+1][MAX+1];
int d[MAX+1][3];

void make_graph(void){
  scanf("%d", &n);

  for(int i=0; i<n; i++){
    int cnt, num, m;

    scanf("%d %d", &num, &cnt);
    G_list[i]=num;

    for(int j=0; j<cnt; j++){
      scanf("%d", &m);
      G[num][m]=1;
    }
  }
}

void check_depth(int data){
  stack<int> S;
  static int tm=0;
  
  S.push(data);
  d[data][0]=++tm;
  d[data][2]=FND;
  
  while(!S.empty()){
    int top=S.top();
    int next=-5;

    for(int i=0; i<n; i++){
      if(G[top][G_list[i]] == 1 && d[G_list[i]][2] == 0){
	next=G_list[i];
	S.push(next);
	d[next][2]=FND;
	d[next][0]=++tm;
	break;
      }
    }

    if(next == -5){
      d[S.top()][2]=CMP;
      d[S.top()][1]=++tm;
      S.pop();
    }

  }
}

void set_depth(void){

  for(int i=0; i<n; i++){
    if(d[G_list[i]][2] == 0) check_depth(G_list[i]);
  }
}

void print(void){

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

int main(void){

  make_graph();
  set_depth();
  print();
  
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<numeric>
#include<string>
#include<cmath>
#include<set>
using namespace std;

int t = 1;
int first[101] = {0};
int last[101] = {0};
void dfs(vector<vector<int> > &graph, int v, set<int> &seen){
	seen.insert(v);
	first[v] = t;
	t++;
	for (int i=0;i<graph[v].size();i++){
		int nxt = graph[v][i];
		if (seen.count(nxt)) continue;
		dfs(graph, nxt, seen);
	}
	last[v] = t;
	t++;
}



int main(){
	int n; cin >> n;
	vector<vector<int> > graph(n+1);
	for (int i = 0; i < n; i++){
		int v, k; cin >> v >> k;
		for (int j = 0; j < k; j++) {
			int in; cin >> in;
			graph[v].push_back(in);
		}
	}

	set<int> seen;
	for (int i=1;i<n+1;i++){
		if (seen.count(i)) continue;
		dfs(graph,i,seen);
	}


	for (int i=1;i<n+1;i++){
		cout << i << " " << first[i] << " " << last[i] << endl;
	}

	return 0;
}