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>
using namespace std;
#include<stdio.h>

int G[101][102];
int found[101];
int comp[101];   // complete.
int t;  // time.

typedef struct box{ int val; box* next; } box_t;  // stack.

box_t* init()
{
    box_t* head = new box_t;
    head->val = -1;
    head->next = NULL;
    return head;
}

bool isEmpty(box_t* head){ return (head->next == NULL ? true : false); }

box_t* push(box_t* head, int data)
{
    box_t* box = new box_t;
    box->val = data;
    box->next = head->next;
    head->next = box;
    return box;
}

int pop(box_t* head)
{
    if(isEmpty(head)){ return -1; }
    box_t* box = head->next;
    int val;
    head->next = box->next;
    val = box->val;
    delete box;
    return val;
}

int front(box_t* head)
{
    int val;
    if(isEmpty(head)){ return -1; }
    val = head->next->val;
    return val;
}

box_t* stack = init();

void search_loop(int i)
{
    int j, k;
    while(1){
        if(found[i] == 0){
            t++; found[i] = t;
            push(stack, i);
        }
        for(k = G[i][0]; G[i][k] != 0 && found[G[i][k]] != 0; k++);
        if(G[i][k] == 0){
            if(isEmpty(stack)){ return; }
            else{
                j = pop(stack);
                t++; comp[j] = t;
                i = front(stack);
            }
        }else{
            G[i][0] = k + 1;
            i = G[i][k];
        }
    };
    return;
}

int main()
{
    int n, i, j, a, b, e;
    scanf("%d", &n);
    for(i = 1; i <= n; i++){
        G[i][0] = 1;
        for(j = 1; j <= n + 1; j++){ G[i][j] = 0; } }

    for(i = 1; i <= n; i++){
        scanf("%d %d", &a, &e);
        for(j = 1; j <= e; j++){
            scanf("%d", &b); G[a][j] = b; } }  // adjacent representation.

    for(i = 1; i <= n; i++){ found[i] = 0; comp[i] = 0; }
    t = 0;
    while(1){
        for(i = 1; i <= n; i++){
            if(found[i] == 0) break;
        }
        if(i > n) break;
        search_loop(i);
    };

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

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

int d[101]={0};
int f[101]={0};
int AdjM[101][101]={0};
int lapse=0;

void dfs(int cur){
    ++lapse;
    d[cur]=lapse;
    //cerr<<"visiting "<<cur<<" "<<lapse<<"\n";
    for(int dst=1;dst<101;++dst){
        if(AdjM[cur][dst]!=0 && d[dst]==0){
            dfs(dst);
        }
    }
    ++lapse;
    f[cur]=lapse;
}

int main(){
    int N;
    cin>>N;
    int id,edgnum,adj;
    for(int i=0;i<N;++i){
        cin>>id>>edgnum;
        for(int j=0;j<edgnum;++j){
            cin>>adj;
            AdjM[id][adj]+=1;
        }
    }

    dfs(1);

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

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

using namespace std;

void dfs(int);
#define N 100
int t = 0;
int s[N], f[N], color[N];
int a[N][N];

int main(int argc, char const *argv[]) {
  int n;  cin >> n;
  for (int i = 0; i < n; ++i) {
    int u, k;  cin >> u >> k;
    for (int j = 0; j < k; ++j) {
      int v;  cin >> v;
      a[u - 1][v - 1] = 1;
    }
  }
  for (int i = 0; i < n; ++i) {
    color[i] = 1;
  }
  for (int i = 0; i < n; ++i) {
    if (color[i] == 1) {
      dfs(i);
    }
  }
  for (int i = 0; i < n; ++i) {
    cout << i + 1 << " " << s[i] << " " << f[i] << '\n';
  }

  return 0;
}

void dfs(int x) {
  color[x] = 2;
  s[x] = ++t;
  for (int i = 0; i < N; ++i) {
    if (a[x][i] == 0) {
      continue;
    }
    if (color[i] == 1) {
      dfs(i);
    }
  }
  color[x] = 3;
  f[x] = ++t;
}

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

const int MAX_N = 100;
vector<int> G[MAX_N];
int d[MAX_N], f[MAX_N];
bool used[MAX_N];

int stamp;

void dfs(const int v) {
    d[v] = stamp++;
    used[v] = true;
    for(int i = 0; i < (int)G[v].size(); i++) {
        int u = G[v][i];
        if(used[u] == false) dfs(u);
    }
    f[v] = stamp++;
}

int main() {
    int N; cin >> N;
    for(int i = 0; i < N; i++) {
        int u, k; cin >> u >> k; u--;
        while(k--) {
            int v; cin >> v; v--;
            G[u].push_back(v);
        }
        sort(G[u].begin(), G[u].end());
    }

    fill(used, used + N, false);
    stamp = 1;
    for(int i = 0; i < N; i++) {
        if(used[i] == false) dfs(i);
    }

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

C++: #include<iostream>
#define N 101
using namespace std;

int n,d[N][N],m[N],f[N],s[N],ti;
void dfs(int t){
  if(s[t]==1) return;
  ti++,m[t]+=ti,s[t]=1;
  for(int i=1;i<=n;i++) if(d[t][i]==1 && s[i]==0)dfs(i);
  ti++,f[t]+=ti;
}

int main(){
  int nx,s,fst;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>fst>>nx;
    for(int j=0;j<nx;j++){
      cin>>s;
      d[fst][s]=1;
    }
  }
  for(int i=1;i<=n;i++) dfs(i);
  for(int i=1;i<=n;i++) cout<<i<<" "<<m[i]<<" "<<f[i]<<endl;
  
  return 0;
}