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 <sstream>
#include <cstdio>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <functional>

using namespace std;
using ll = long long int;
#define rep(i,n) for(int i = 0; i < n; i++)
#define FOR(i, a, b)  for(int i = (a); i < (b) ; i++)

#define pb push_back
#define SORT(v,n) sort(v, v+n)
#define ALL(x) (x).begin(),(x).end()
#define debug(x) cerr << #x << ": " << x << '\n'
#define elif else if
#define itn ll
#define int ll
const int INF = 100100100;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
///                →,↑,←,↓,↗,↖,↙,↘
int dx[8] = { 1, 0, -1, 0, 1, -1, -1, 1 };
int dy[8] = { 0, 1, 0, -1, 1, 1, -1, -1 };

static const int N = 100;
static const int White = 0;
static const int Gray = 1;
static const int Black = 2;
int d[N], f[N],tt;
int color[N],n,M[N][N];


void dfs_visit(int u) {
	int v;
	d[u] = ++tt;
	color[u] = Gray;
	rep(v,n){
		if (M[u][v] == 0) continue;
		if (color[v] == White) dfs_visit(v);
	}
	color[u] = Black;
	f[u] = ++tt;
}

void dfs() {
	int u;
	rep(u, n)color[u] = White;
	rep(u, n) {
		if (color[u] == White) dfs_visit(u);
	}
	rep(u, n) {
		cout << u + 1 << ' ' << d[u] << ' ' << f[u] << '\n';
	}
}

signed main() {
	ios::sync_with_stdio(false);
	cin >> n;
	int i;
	rep(i, n) {
		int u, k, v;
		cin >> u >> k;
		u--;
		int j;
		rep(j, k) {
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}
	dfs();
	return 0;
}

C++: #include <stdio.h>
int n,M[100][100],C[100],d[100],f[100],t;
void visit(int );
void dfs();
int main(){
  int u,v,k,i,j;
  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;
}
void dfs(){
  int i;
  for(i=0;i<n;i++)C[i]=0;
  t=0;
  for(i=0;i<n;i++)if(C[i]==0)visit(i);
  for(i=0;i<n;i++)printf("%d %d %d\n",i+1,d[i],f[i]);
}
void visit(int k){
  int i;
  C[k]=1;
  d[k]=++t;
  for(i=0;i<n;i++){
    if(M[k][i]==0)continue;
    if(C[i]==0)visit(i);
  }
  C[k]=2;
  f[k]=++t;
}

C++: #include <stdio.h>
#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(void){
    int u,v,k,i,j;
    
    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();
}

C++: #include <iostream>
#include <vector>
using namespace std;
using Graph = vector<vector<int>>;

// 深さ優先探索
vector<bool> seen;
vector<int> start_ptr;
vector<int> end_ptr;
void dfs(const Graph &G, int v, int &ptr) {
    seen[v] = true;
    start_ptr[v]=ptr;
    ptr++;
    for (auto next_v : G[v]) { 
        if (seen[next_v]) continue;
        dfs(G, next_v, ptr); // 再帰的に探索
    }
    end_ptr[v]=ptr;
    ptr++;
}

int main() {
    // 頂点数と辺数
    int N; cin >> N;

    // グラフ入力受取
    Graph G(N);
    for (int i = 0; i < N; ++i) {
        int a, b;
        cin >> a >> b;
        for(int j=0;j<b;j++){
            int v; cin >>v;
        
        G[a-1].push_back(v-1);
        }
    }

    // 全頂点が訪問済みになるまで探索
    seen.assign(N, false);
    int ptr=1;
    start_ptr.resize(N);
    end_ptr.resize(N);
    for (int v = 0; v < N; ++v) {
        if (seen[v]) continue; // v が探索済みだったらスルー
        dfs(G, v, ptr); // v が未探索なら v を始点とした DFS を行う
    }
    for(int i=0;i<N;i++){
    cout << i+1 <<" "<<start_ptr[i]<<" "<<end_ptr[i]<< endl;
    }
}

C++: #include<stdio.h>
using namespace std;
#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 u,v,k,i,j;
    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();
}