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<stdio.h>
#include<stack>
using namespace std;
int tu[1000][1000];
int a[10000];
int an[10000];
int d[10000];
int f[10000];
int shijian,n;
int next(int q){
for(int i=an[q];i<n;i++){
    an[q]=i+1;
    if(tu[q][i])return i;
}
return -1;
}
void sou(int u){
     stack<int > s;
     s.push(u);
     a[u]=2;
     d[u]=++shijian;
     while(!s.empty()){
        int x=s.top();
        int v=next(x);
        if(v!=-1){
            if(a[v]==1){
                a[v]=2;
                d[v]=++shijian;
                s.push(v);
            }
        }
        else {
            s.pop();
            a[x]=3;
            f[x]=++shijian;
        }
     }
}
void shensou(){
     for(int u=0;u<n;u++){
        a[u]=1;
        an[u]=0;
     }
     shijian=0;
     for(int u=0;u<n;u++){
        if(a[u]==1)sou(u);
     }
     for(int u=0;u<n;u++){
         printf("%d %d %d\n",u+1,d[u],f[u]);
     }
}


int main(){
   int v;
   int m;
   int x;
   scanf("%d",&n);
   for(int i=0;i<n;i++){
        scanf("%d%d",&v,&m);
        v--;
        for(int j=0;j<m;j++){
            scanf("%d",&x);
            x--;
            tu[v][x]=1;
        }
   }
   shensou();
return 0;
}

C++: #include<iostream>
using namespace std;
int M[100][100] = {};
int color[100] = {};
int d[100] = {}, f[100] = {};
int cot=0;
int n;

void dps(int u) {
	if (color[u] == 0) {
		cot++;
		d[u] = cot;
		color[u]++;
	}

	for (int t = 0;t < n;t++) {
		if (M[u][t] == 1) {
			if(color[t]==0){
			    dps(t);
			}
			
			
		}
	}
	if (color[u] == 1) {
        cot++;
	    f[u] = cot;
		color[u]++;
	}
	
	return;

}
int main(){
	int k,m,j;
	cin >> n;
	for (int i = 0;i < n;i++) {
		cin >> m>>k;
		for (int l = 0;l < k;l++) {
			cin >> j;
			M[m - 1][j - 1] = 1;
		}
	}
	for (int i = 0;i < n;i++) {
		if (color[i] == 0) {
			dps(i);
		}
	}


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

	return 0;
}

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

enum Status {WHITE, GRAY, BLACK};

stack<int> stc;
Status *status;
int *discovered, *finished;
vector<vector<int> > a;
int n, timer;

void dfs(int i){
        if(status[i]==BLACK) return;
        if(status[i]==WHITE){
                discovered[i] = ++timer;
                status[i] = GRAY;
        }
        stc.push(i);

        for(int j=0;j<a[i].size();j++) dfs(a[i][j]);

        if(status[i]==GRAY){
                finished[i] = ++timer;
                status[i] = BLACK;
        }
        stc.pop();
}

int main(){

        cin>>n;
        a = vector<vector<int> >(n, vector<int>());
        status = new Status[n];
        discovered = new int[n];
        finished = new int[n];

        int m, k, r;
        for(int i=0;i<n;i++){
                cin>>r;
                cin>>m;
                for(int j=0;j<m;j++){
                        cin>>k;
                        a[r-1].emplace_back(k-1);
                }
        }
        for(int i=0;i<n;i++) status[i] = WHITE;

        timer = 0;
        dfs(0);


        for(int i=0;i<n;i++){
                cout<<i+1<<" "<<discovered[i]<<" "<<finished[i]<<endl;
        }
        return 0;
}

C++: #include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
using namespace std;
int n, t, d[101], f[101];
vector< vector<int> >m(101);


void dfs(int u){
    d[u] = ++t;
    int v;
    for(int i=0; i<m[u].size(); i++){
        v = m[u][i];
        if(d[v]==-1){
            dfs(v);
        }
    }
    f[u] = ++t;
    return;
}

int main(){
    //freopen("in.txt", "r", stdin);
    scanf("%d", &n);
    for(int i=0; i<n; i++){
        int id, d, to;
        scanf("%d %d", &id, &d);
        for(int j=0; j<d; j++){
            scanf("%d", &to);
            m[id].push_back(to);
        }
    }
    memset(d, 255, sizeof(d));
    t = -0;

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

C++: #include <iostream>
#include <vector>

/*
 * ref. http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_B
 */

using namespace std;

const int MAX_N = 100;

int n;
int d[MAX_N];
int f[MAX_N];
vector<int> adjlist[MAX_N];

int dfs(const int id, int timestamp) {
    if (d[id - 1] > 0) {
        return timestamp;
    }

    timestamp++;
    d[id - 1] = timestamp;
    for (int i = 0; i < (int) adjlist[id - 1].size(); i++) {
        timestamp = dfs(adjlist[id - 1][i], timestamp);
    }
    timestamp++;
    f[id - 1] = timestamp;

    return timestamp;
}

int main(void) {
    cin >> n;

    for (int i = 0; i < n; i++) {
        int id, m;
        cin >> id >> m;
        for (int j = 0; j < m; j++) {
            int x;
            cin >> x;
            adjlist[id - 1].push_back(x);
        }
    }

    int timestamp = 0;
    for (int i = 0; i < n; i++) {
        int id = i + 1;
        timestamp = dfs(id, timestamp);
    }

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

    return 0;
}