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 <algorithm>
#include <vector>
#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
using namespace std;
class Graph{
private:
  int node;
  int edge_num;
  vector<vector<int>> edge;  
  vector<int> f;
  vector<int> d;
  int time;
public:
  //***************Constractor****************************
  Graph(int n,vector<int> a,vector<int> b){
    node = n;
    edge_num = a.size();
    time = 1;
    edge.resize(node);
    f.resize(node,0);
    d.resize(node);    
    rep(i,edge_num){
      edge[a[i]].push_back(b[i]);
    }
  }

  //***********************************************
  
  void simple_dfs(int v){
    f[v] = time++;
    for(auto w:edge[v]){
      if(f[w]>0) continue;
      simple_dfs(w);
    }
    d[v] = time++;
  }

  void run_dfs(int s){//check each node can reach goal
    rep(i,node){
      if(f[i]<=0) simple_dfs(i);
    }
  }

  void show(){
    rep(i,node){
      cout << i+1 << " " << f[i] << " " << d[i] << "\n";
    }
  }
};


int main()
{
  int n;
  cin >> n;
  vector<int> a,b;
  rep(i,n){
    int aa;cin >> aa;aa--;
    int m;cin >> m;
    rep(i,m){
      int bb;cin >> bb;bb--;
      a.push_back(aa);
      b.push_back(bb);      
    }
  }

  Graph gp(n,a,b);
  gp.run_dfs(0);
  gp.show();
  
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;

vector<set<ll>> v(101);
vector<ll> st(101,-1);
vector<ll> et(101,-1);

ll dfs(ll n,ll time) {
  st[n]=time;
  time++;
  for(auto p:v[n]) {
    if(st[p]<0) {
      time=dfs(p,time);
    }
  }
  et[n]=time;
  return time+1;
}

int main() {
  ll n;
  cin >> n;
  for(ll i=0;i<n;i++) {
    ll f,tn;
    cin >> f >> tn;
    for(ll j=0;j<tn;j++) {
      ll temp;
      cin >> temp;
      v[f].insert(temp);
    }
  }
  for(ll i=1;i<=n;i++) {
    v[0].insert(i);
  }
  dfs(0,0);
  for(ll i=1;i<=n;i++) {
    cout << i << " " << st[i] << " " << et[i] << endl;
  }
}

C++: #include <iostream>
#include <stdio.h>
#include <vector>
#include <utility>
#include <string>
#include <algorithm>
#include <cmath>
#include <queue>
 
typedef long long ll;

#define rep(i,n) for(ll i = 0; i < n; i++)
 
using namespace std;
 
const ll INF = ll(1e18)+1;
const double PI=3.14159265358979323846;

vector<vector<int> > G(105);
vector<int> go(105), back(105);
vector<bool> seen(105);
int now=1;

void dfs(int s){

  go[s]   = now++;
  seen[s] = true;

  rep(i,G[s].size()){
    if(seen[G[s][i]]) continue;    
    dfs(G[s][i]);
  }
  
  back[s] = now++;
}

int main(){
  int n;
  cin >> n;
  rep(i,n){
    int u,k;
    cin >> u >> k;
    rep(j,k){
      int x;
      cin >> x;
      G[u].push_back(x);
    }    
  }
  for(int i=1; i<=n; i++) if(!seen[i]) dfs(i);
  rep(i,n){
    cout << i+1 << " " << go[i+1] << " " << back[i+1] << endl;
  }
}

C++: // 深さ優先探索
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>

using namespace std;

#define MAX_N 100
// 値の定義
const int EXIST = 1;
const int NO_EXIST = 0;

const int WHITE = 0;// 未訪問
const int GRAY = 1; // 訪問中
const int BLACK = 2;// 訪問完了

// グラフ情報を保持する配列
int ary_graph[MAX_N + 1][MAX_N + 1];

// 各頂点の訪問状態を保持する配列
int color[MAX_N + 1];

// 発見時刻と完了時刻を保持する構造体
typedef struct
{
    int start_time;
    int end_time;
}SearchTime;

SearchTime st_SearchTime[MAX_N];
int search_T = 0;

void depthFirstSearch(int now_vertex, int vertex_num);

int main(void)
{
    int n, u, num, v_num;

    for(int i = 0; i < MAX_N + 1; i++)
    {
        color[i] = WHITE;

        for(int j = 0; j < MAX_N + 1; j++)
        {
            // 配列の初期化
            ary_graph[i][j] = NO_EXIST;
        }
    }

    cin >> n;

    for(int i = 0; i < n; i++)
    {
        cin >> u;
        cin >> num;

        for(int j = 0; j < num; j++)
        {
            // 隣接点を記憶する
            cin >> v_num;
            ary_graph[u][v_num] = EXIST;
        }
    }

    // 深さ優先探索を実施
    for(int i = 1; i <= n; i++)
    {
        if( color[i] == WHITE )
        {
            depthFirstSearch(i, n);
        }
    }

    // 結果の表示
    for(int i = 1; i <= n; i++)
    {
        printf("%d %d %d\n", i, st_SearchTime[i].start_time, st_SearchTime[i].end_time);
    }

    return 0;
}

// 深さ優先探索を実施する関数
// now_vertex : 現在の頂点のNo.
// next_vertex : 次の頂点のNo.
// vertex_num : グラフの頂点数
void depthFirstSearch(int now_vertex, int vertex_num)
{
    // 訪問中
    color[now_vertex] = GRAY;

    // 発見時刻の設定
    search_T++;
    st_SearchTime[now_vertex].start_time = search_T;

    for(int i = 1; i <= vertex_num; i++)
    {
        if( color[i] == WHITE
            && ary_graph[now_vertex][i] == EXIST )
        {
            depthFirstSearch(i, vertex_num);
        }
    }

    // 訪問完了
    color[now_vertex] = BLACK;

    // 終了時刻の設定
    search_T++;
    st_SearchTime[now_vertex].end_time = search_T;

    return;
}