Go: package main

/*
深さ優先探索
*/

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

C++: #include<bits/stdc++.h>
using namespace std;
const int MAXN =  100+7;
struct node {
    int id;
    node* next;
};
node* g[MAXN];
bool visit[MAXN];
int d[MAXN];
int f[MAXN];
int mytime;
stack<int> s;
void dfs(int i){
    node* p = g[i];
    while(p->next!=NULL){
        p=p->next;
        if(visit[p->id]==false){
            s.push(p->id);
            mytime++;
            d[p->id] = mytime;
            visit[p->id] = true;
            dfs(p->id);
        }

    }
    s.pop();
    mytime++;
    f[i] = mytime;

}
int main() {
//    freopen("../in.txt", "r", stdin);
    memset(visit, false, sizeof(visit));
    int n;
    scanf("%d", &n);
    int i;
    for(i = 1; i <= n; i++) {
        g[i] = (node*)malloc(sizeof(node));
        g[i]->next = NULL;
    }
    for(i = 0; i < n; i++) {
        int num;
        int k;
        scanf("%d", &num);
        scanf("%d", &k);
        int j;
        for(j = 0; j < k; j++) {
            int r;
            scanf("%d", &r);
            node* t = (node*)malloc(sizeof(node));
            t->id = r;
            t->next = NULL;
            node* p = g[num];
            while(p->next != NULL) p = p->next;
            p->next = t;
        }
    }
    mytime = 0;
    while(true){
        int u;
        int g = -1;
        for(u = 1; u <= n; u++){
            if(visit[u]==false){
                g = u;
                break;
            }
        }
        if(g==-1){
            break;
        }
        s.push(g);
        mytime++;
        d[g] = mytime;
        visit[g] = true;
        dfs(g);
    }

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

C++: #include <bits/stdc++.h>
#define rep(i, a, b) for (int i = a; i < (b); i++)
#define rrep(i, a, b) for (int i = a; i >= (b); i--)
#define all(x) (x).begin(), (x).end()
using namespace std;
using ll = long long;
using P = pair<int, int>;
template <class T>
inline bool chmin(T& a, T b) {
   if (a > b) {
      a = b;
      return true;
   }
   return false;
}
template <class T>
inline bool chmax(T& a, T b) {
   if (a < b) {
      a = b;
      return true;
   }
   return false;
}
const int INF = 2e9;
const int MOD = 1e9 + 7;

int main() {
   int n;
   cin >> n;
   vector<vector<int>> to(n);
   rep(i, 0, n) {
      int u, k;
      cin >> u >> k;
      u--;
      rep(j, 0, k) {
         int v;
         cin >> v;
         v--;
         to[u].push_back(v);
      }
   }
   vector<int> d(n), f(n), color(n);
   int t = 0;
   function<void(int)> dfs = [&](int u) {
      if (color[u] != 0) return;
      color[u] = 1;
      d[u] = ++t;
      for (int i = 0; i < to[u].size(); i++) {
         if (color[to[u][i]] == 0) {
            dfs(to[u][i]);
         }
      }
      color[u] = 2;
      f[u] = ++t;
   };
   rep(i, 0, n) dfs(i);
   rep(i, 0, n) printf("%d %d %d\n", i + 1, d[i], f[i]);
   return 0;
}

C++: #include <iostream>

#define N_MAX 100

using namespace std;

int t = 1;
int adj_matrix[N_MAX][N_MAX];
int d[N_MAX];
int f[N_MAX];

void dfs(int v, int n)
{
    if (d[v] == 0) {
        d[v] = t;
        t++;
    }
    for (int i = 0; i < n; i++) {
        if (adj_matrix[v][i] != 0) {
            dfs(i, n);
        }
    }
    if (f[v] == 0) {
        f[v] = t;
        t++;
    }
}

int main()
{
    int n, u, k, v;
    cin >> n;
    for (int i = 0; i < n; i++) {
        d[i] = 0;
        f[i] = 0;
    }

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

    for (int i = 0; i < n; i++) {
        cin >> u;
        cin >> k;
        for (int j = 0; j < k; j++) {
            cin >> v;
            adj_matrix[u-1][v-1] = 1;
        }
    }

    dfs(0, n);

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

    return 0;
}

C++: #include <iostream>

using namespace std;

int n;
int A[110][110];
int d[110];
int f[110];
string color[110];
int t = 0;

void dfs_visit(int u) {
  color[u] = "GRAY";
  d[u] = ++t;
  for (int v = 0; v < n; v++) {
    if (A[u][v] == 1 && color[v] == "WHITE") {
      dfs_visit(v);
    }
  }
  color[u] = "BLACK";
  f[u] = ++t;
}

void dfs() {
  // color 初期化
  for (int i = 0; i < n; i++) {
    color[i] = "WHITE";
  }
  for (int u = 0; u < n; u++) {
    if (color[u] == "WHITE") {
      dfs_visit(u);
    }
  }
}

int main() {
    cin >> n;
    int u, k, v;
    for (int i = 0; i < n; i++) {
      cin >> u >> k;
      for (int j = 0; j < k; j++) {
        cin >> v;
        A[u-1][v-1] = 1;
      }
    }
    dfs();

    // answer
    for (int i = 0; i < n; i++) {
      cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
}