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>
using namespace std;


void solve(int);

typedef struct{
  int k;
  vector<int> ls;
  int f,d;
}node_t;

node_t node[101];
int t=0;

int main(){
  int n;
  int u;

  cin >> n;
  for(int i=0; i<n; i++){
    cin >> u; 
    cin >> node[u].k;
    node[u].ls.resize(node[u].k);
    node[u].d = node[u].f = -1;
    for(int j=0; j<node[u].k; j++){
      cin >> node[u].ls[j];
    }
    sort(node[u].ls.begin() , node[u].ls.end());
  }
 
  solve(1);

  for(int i=1;i<=n; i++){
    cout << i << ' ' << node[i].d << ' ' << node[i].f << endl;
  }

  return 0;
}



void solve(int id){
  t++;
  if(node[id].d == -1)node[id].d = t;
  else {t--;return;}

  for(int i=0; i<node[id].k; i++){
    solve(node[id].ls[i]);
  }
  node[id].f = ++t;
}

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];

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;

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

    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;
        }
    }

    dfs();

    return 0;
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int arisutoteresu[200][200] = {0};
int imap[200][200] = {0};
int n,u,k[200];
int GetIt[200]={0};
int FinIt[200]={0};
bool used[200] = {false};
int fincou=1;
void dfs(int where,int find){
  fincou++;
 
  GetIt[where]=find;
  if(k[where] != 0){
    for(int i=0;i<k[where];i++){
      if(!used[where]){
	dfs(imap[where][i],find+1);
	fincou++;
	used[where] = true;
      }
    }
  }
    FinIt[where] = fincou;
    
}

int main(){
 
  int ad;
  
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    cin >> u;
    cin >> k[u];
    for(int j=0;j<k[u];j++){
      cin >> ad;
      arisutoteresu[u][ad] = 1;
      imap[u][j] = ad; 
    }
  }


  for(int j=0;j<n;j++)used[j] = false;
  dfs(1,1);

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

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <vector>
#include <stack>
using namespace std;
#define maxn 105
const int WHITE = 0;
const int GRAY  = 1;
const int BLACK = 2;
int g[maxn][maxn];
int d[maxn],f[maxn];
stack<int> s;
int color[maxn];
int t,n;
void dfs_visit(int u)
{
    color[u]=GRAY;
    d[u]=++t;
    for(int v=1;v<=n;v++)
    {
        if(g[u][v]==0) continue;
        if(color[v]==WHITE)
            dfs_visit(v);
    }
    color[u]=BLACK;
    f[u]=++t;
}
void dfs()
{
    for(int u=1;u<=n;u++)
        color[u]=WHITE;
    for(int u=1;u<=n;u++)
    {
        if(color[u]==WHITE)
            dfs_visit(u);
    }
    for(int u=1;u<=n;u++)
        printf("%d %d %d\n",u,d[u],f[u]);
}
int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        int u,k;
        scanf("%d%d",&u,&k);
        for(int j=1;j<=k;j++)
        {
            int v;
            scanf("%d",&v);
            g[u][v]=1;
        }
    }
    dfs();
    return 0;
}

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

static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int M[N][N] = {0}, color[N] = {0}, d[N], f[N], tt = 0, n;

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++) {
    if (color[u] == WHITE) {
      dfs_visit(u);
    }
  }

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

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

  cin >> n;
  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;
}