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;

// 総数を1000000007で割った余り
const long long mod = 1e9 + 7;

using ll  = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define ull unsigned long long
#define ld long double
#define vi vector<int>
#define vll vector<ll>
#define vc vector<char>
#define vs vector<string>
#define vpii vector<pii>
#define vpll vector<pll>

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; i++)
#define rep1(i, n) for (int i = 1, i##_len = (n); i <= i##_len; i++)
#define repr(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define rep1r(i, n) for (int i = ((int)(n)); i >= 1; i--)

#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

#define SORT(v, n) sort(v, v + n);
// #define SORT(v, n) stable_sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RSORT(x) sort(rall(x));
#define pb push_back
#define mp make_pair

#define INF (1e9)
#define PI (acos(-1))
#define EPS (1e-7)

ull gcd(ull a, ull b) { return b ? gcd(b, a % b) : a; }
ull lcm(ull a, ull b) { return a / gcd(a, b) * b; }

const int N     = 100;
int       white = 0;
int       gray  = 1;
int       black = 2;

int n, m[N][N];
int color[N], d[N], f[N], tt;

// 再帰による深さ優先探索
void dfs_visit(int u) {
    color[u] = gray;
    d[u]     = ++tt;  //最初の訪問
    rep(v, n) {
        if (m[u][v] == 0) continue;
        if (color[v] == white) {
            dfs_visit(v);
        }
    }
    color[u] = black;
    f[u]     = ++tt;  // 訪問の完了
}

void dfs() {
    //初期化
    rep(u, n) color[u] = white;
    tt                 = 0;
    rep(u, n) {
        // 未訪問のuを始点として深さ優先探索
        if (color[u] == white) dfs_visit(u);
    }
    rep(u, n) { cout << u + 1 << " " << d[u] << " " << f[u] << endl; }
}

// 再帰による深さ優先探索
int main() {
    int u, v, k;
    cin >> n;
    rep(i, n) rep(j, n) m[i][j] = 0;

    rep(i, n) {
        cin >> u >> k;
        u--;
        rep(j, k) {
            cin >> v;
            v--;
            m[u][v] = 1;
        }
    }
    dfs();

    return 0;
}

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

int r[101][101];
int d[101], f[101], num, visit[100]={0}, p=1;

void dfs(int n){
    if(visit[n]!=1){
        visit[n] = 1;
        d[n] = p++;
        for(int i=1; i<num+1; i++)
            if(r[n][i]==1) dfs(i);
        f[n] = p++;
    }
}

int main(void){
    int u, k, v;
    cin >> num;
    for(int i=0; i<num; i++){
        cin >> u >> k;
        for(int j=0; j<k; j++){
            cin >> v;
            r[u][v]=1;
        }
    }
    for(int i=1; i<num+1; i++){
        if(visit[i]!=1) dfs(i);
    }
    for(int i=1; i<num+1; i++)
        cout << i << " " << d[i] << " " << f[i] << endl;
    return 0;
}

C++: #include <iostream>
#include <algorithm>
 
using namespace std;
 
typedef struct{
  int begin;
  int end;
  bool f;
}fint;
fint T[101];
 
int times = 1;
int n;
int graph[101][101];
 
void bfs(int now){
 
  T[now].f = true;
  T[now].begin = times++;
 
  for( int i = 1 ; i <= n; i++ ){
    if( graph[now][i] == 1 && !T[i].f ) bfs(i);
  }
  T[now].end = times++;
 
}
 
int main(void){
 
  int s,t,u;
  cin >> n;
  for( int i = 0 ; i < n ; i++ ){
    cin >> s >> t;
    for( int j = 1 ; j <= t ; j++ ){
      cin >> u;
      graph[s][u] = 1;
    }
  }
  for( int i = 1 ; i <= n ; i++ ){
    T[i].begin = 0;
    T[i].end = 0;
    T[i].f = false;
  }
  for( int i = 1 ; i <= n ; i++ ){
    if( !T[i].f ) bfs(i);
  }
 
  for( int i = 1 ; i <= n ; i++ ){
    cout << i << " " << T[i].begin << " " << T[i].end << endl;
  }
 
 
  return 0;
}

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

typedef pair<int, int> edge;

int vernum[101];
edge path[101][101];
int n;

edge found[101];

int t=0;
void dfs(int v){
    t++;
    found[v].first = t;
    int i=0;
    while(1){
        if(!path[v][i].first)
            break;
        if(!found[path[v][i].second].first){
            dfs(path[v][i].second);
        }
        i++;
    }
    t++;
    found[v].second = t;
}

int main() {
    int i, j;
    ios_base::sync_with_stdio(0);
    
    int e, v;
    cin >> n;
    
    for(i=1; i<=n; i++){
        cin >> vernum[i];
        cin >> e;
        for(j=0; j<e; j++){
            cin >> v;
            path[i][j] = make_pair(i, v);
        }
    }
    
    for(i=1; i<=n; i++){
        if(!found[i].first)
            dfs(i);
    }
    
    for(i=1; i<=n; i++){
        cout << vernum[i] << " " << found[i].first << " " << found[i].second << endl;
    }
    
    
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int g[105][105],b[105],f[105],cnt=1,n,is[105];

void dfs(int v)
{
    is[v]=1;
    b[v]=cnt++;
    for(int i=1;i<=n;i++){
        if(i==v) continue;
        if(g[v][i]&&!is[i]) dfs(i);
    }
    f[v]=cnt++;
}

int main()
{
    int v1,d,v2;
    cin>>n;
    memset(g,0,sizeof g);
    memset(is,0,sizeof is);
    for(int i=0;i<n;i++){
        cin>>v1>>d;
        for(int i=0;i<d;i++){
            cin>>v2;
            g[v1][v2]=1;
        }
    }
    dfs(1);
    for(int i=1;i<=n;i++){
        cout<<i<<" "<<b[i]<<" "<<f[i];
        if(i!=n) cout<<endl;
    }
    return 0;
}