Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#include<cstring>
#include<vector>
#include<stack>
using namespace std;
#define INT(x) int x; scanf("%d",&x)
#define INPUT(x) scanf("%d",&x)
#define REP1(x,n) for(int x = 0; x < n; x++)
#define REP2(x,s,e) for(int x = s; x <= e; x++)
#define BR printf("\n")
#define INF 2000000000

vector<int> V[100];//0 origin
bool complete[100] = {};
stack<int> S;
int time_ = 1;
int NodeStump[100][2];//find,end

void DFS(){
    NodeStump[S.top()][0] = time_;
    time_++;//d++
    if (S.empty()) return;
    
    REP1(i,V[S.top()].size()){
        if (!complete[V[S.top()][i]]){
            S.push(V[S.top()][i]);
            DFS();
        }
    }
    
    complete[S.top()] = true;
    NodeStump[S.top()][1] = time_;
    S.pop();
    time_++;//d--
}

int main(){
    INT(N);
    
    REP1(i,N){
        int from,n;
        scanf("%d %d",&from,&n);
        REP1(j,n){
            INT(to);
            V[i].push_back(to - 1);
        }
    }
    
    S.push(0);
    
    DFS();
    
    REP1(i,N){
        printf("%d %d %d\n",i+1,NodeStump[i][0],NodeStump[i][1]);
    }
    
    return 0;
}

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

using namespace std;

int  n, M[100][100], d[100], f[100], color[100], time, nt[100], W = 0, G = 1, B = 2;

int next (int u) {

    int v;
    for (v = nt[u]; v < n; v++) {
        nt[u] = v + 1;
        if (M[u][v] != 0) {
            return v;
        }
    }
    return -1;

}

void dfs_visit (int r) {

    int i, u, v;

    for (i = 0; i < n; i++) {
        nt[i] = 0;
    }

    stack<int> S;
    S.push(r);
    color[r] = G;
    d[r] = ++time;

    while (!S.empty()) {
        u = S.top();
        v = next (u);
        if (v != -1) {
            if (color[v] == W) {
                color[v] = G;
                d[v] = ++time;
                S.push(v);
            }
        } else {
            S.pop();
            color[u] = B;
            f[u] = ++time;
        }
    }

}

void dfs () {

    int i, u;

    for (i = 0; i < n; i++) {
        color[i] = W;
        nt[i] = 0;
    }
    time = 0;

    for (u = 0; u < n; u++) {
        if (color[u] == W) {
            dfs_visit(u);
        }
    }

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

}

int main () {

    int u, k, v, i, j;

    cin >> n;
    for (i = 0; i < n; i++) {
        for (j = 0; j < n; j++) {
            M[i][j] = 0;
        }
    }

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

    dfs ();

    return 0;

}

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

using namespace std;

std::vector<int> graph[100];
int d[100],f[100];
int t = 0;

void dfs(int v){
  t++;
  d[v] = t;
  for(const auto &next_v:graph[v]){
    if(d[next_v]==0){
      dfs(next_v);
    }
  }
  t++;
  f[v] = t;
}

int main(){
  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;
      graph[u-1].push_back(v-1);
    }
  }
  
  dfs(0);
  for(int i=0;i<n;++i){
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
  
  return 0;
}

C++: #include<stdio.h>

#define BLACK -1
#define GRAY  -2
#define WHITE -3

void DFSvisit(int);

int G[100][100],d[100],f[100],color[100];
int n,time;

void DFS(int n){
  int i;

  for(i=0;i<n;i++){
    if(color[i]==WHITE){
      DFSvisit(i);
    }
  }
}

void DFSvisit(int u){
  int i;

  color[u]=GRAY;
  time++;
  d[u]=time;

  for(i=0;i<=n;i++){
    if(G[u][i] && color[i]==WHITE){
      DFSvisit(i);
    }
  }
  color[u]=BLACK;
  f[u]=++time;
}

main(){
  int  i,j,k,m;

  scanf("%d",&n);

  for(i=0;i<100;i++){
    for(j=0;j<100;j++){
      G[i][j]=0;
    }
    color[i] = WHITE;
  }

  for(i=0;i<n;i++){ 
    scanf("%d%d",&j,&k);
    for(j=0;j<k;j++){
      scanf("%d",&m);
      G[i][m-1]=1;
    }
  } 
 
  DFS(n);

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

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<bitset>
#include<cctype>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<deque>
#include<functional>
#include<limits>
#include<list>
#include<map>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<queue>
#include<vector>
using namespace std;

#define MOD 1000000007
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL

#define MAX 100

int n, s[MAX] = {}, d[MAX], f[MAX], t = 0;
bool M[MAX][MAX] = {};

void dfs(int u) {
	int v;
	s[u] = 1;
	d[u] = ++t;
	for (int v = 0; v < n; v++) {
		if (M[u][v] == false)continue;
		if (s[v] == 0) {
			dfs(v);
		}
	}
	s[u] = 2;
	f[u] = ++t;
}

int main() {
	cin >> n;

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

	for (int u = 0; u < n; u++) {
		if (s[u] == 0)dfs(u);
	}
	for (int u = 0; u < n; u++) {
		printf("%d %d %d\n", u + 1, d[u], f[u]);
	}
	return 0;
}