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 <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)
using P = pair<int,int>;

/* 大文字を小文字に変換 */
char tolower(char c) {return (c + 0x20);}
/* 小文字を大文字に変換 */
char toupr(char c) {return (c - 0x20);}

// if('A'<=s[i] && s[i]<='Z') s[i] += 'a'-'A';

/*
string s = "abcdefg"
s.substr(4) "efg"
s.substr(0,3) "abc"
s.substr(2,4) "cdef"

// イテレータ要素のインデックス
distance(A.begin(), itr);
*/

const int MAX_N = 105;
const int INF = 1000;

vector<int> to[MAX_N];
int d[MAX_N], f[MAX_N]; // d：発見時刻、f：完了時刻
int t = 0; int n; 

void init(){
    rep(i,MAX_N){
        d[i] = INF, f[i] = INF;
    }
}

void dfs(int u){
    if(d[u] == INF) d[u] = ++t;
    for(auto v: to[u]){
        if(d[v] == INF) dfs(v); // *もう訪問が完了している頂点には不要に寄らない
    }
    if(f[u] == INF) f[u] = ++t;
}

void dfs_init(){
    rep(i,n){
        if(d[i] == INF) dfs(i);
    }
}

int main()
{
    cin >> n;
    init();
    rep(i,n){
        int u, k; cin >> u >> k; --u;
        rep(_,k){
            int v; cin >> v; --v;
            to[u].push_back(v);
        }
    }
    dfs_init();
    rep(i,n){
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
}

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

using namespace std;

vector<int> F;
vector<int> L;
vector<bool> seen;

void dfs(vector<vector<int>> &G,int v,int &t){
    F[v]=t++;

    seen[v]=true;

    for(int i=0;i<G[v].size();i++){
        if(seen[G[v][i]])continue;
        dfs(G,G[v][i],t);
    }

    L[v] = t++; 
}

int main(){

    int n;
    cin >> n;

    vector<vector<int>> G(n);

    for(int i=0;i<n;i++){
        int a,k;
        cin >> a >> k;
        for(int j=0;j<k;j++){
            int b;
            cin >>b;
            G[i].push_back(b-1);
        }
    }

    seen.assign(n,false);
    F.resize(n);
    L.resize(n);
    int t=1;
    
    

    for(int i=0;i<n;i++){
        if(!seen[i])dfs(G,i,t);
        cout << i+1 << " " << F[i] << " " << L[i] << endl;
    }

    return 0;




}

C++: #include <iostream>
#include <string>
#include <vector>
#include <utility>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <bitset>
#include <cstdio>
#include <cmath>

using namespace std;

int cnt = 1; // time stamp
vector<int> seen, visited;

void dfs(vector<vector<int> > graph, int v) {
    if (seen[v] != 0) return;
    seen[v] = cnt;
    cnt++;
    for (int i = 0; i < graph[v].size(); i++) {
        dfs(graph, graph[v][i]);
    }
    visited[v] = cnt;
    cnt++;
}

int main() {
    int n;
    cin >> n;
    vector<vector<int> > graph(n+1);
    for (int i = 1; i <= n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            graph[u].push_back(v);
        }
    }
    seen.assign(n+1, 0);
    visited.assign(n+1, 0);
    for (int i = 1; i <= n; i++) dfs(graph, i);
    for (int i = 1; i <= n; i++) {
        cout << i << " " << seen[i] << " " << visited[i] << endl;
    }
}

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;

  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<stdio.h>

void dfs_visit(int);
void dfs();

#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n,M[N][N];
int color[N],D[N],F[N],t;

int main()
{
  int i,j,u,x,y;

  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,&y);
      u--;
      for(j=0;j<y;j++)
        {
          scanf("%d",&x);
          x--;
          M[u][x]=1;
        }
    }

  dfs();

  return 0;
}

void dfs_visit(int u)
{
  int v;
  color[u]=GRAY;
  D[u]=++t;

  for(v=0;v<n;v++)
    {
      if(M[u][v]==0) continue;
      if(color[v]==WHITE)
        {
          dfs_visit(v);
        }
    }
  color[u]=BLACK;
  F[u]=++t;
}

void dfs()
{
  int u;

  for(u=0;u<n;u++)
    color[u]=WHITE;

  t=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]);
}