Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	timer := 1
	startNode := 1
	for {
		visit(startNode, &timer, childrenMap, timeRecordMap)
		startNode = findStartNode(childrenMap, timeRecordMap)
		if startNode < 0 {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	return x
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include<stdio.h>
#define N 105
#define WHITE 0
#define GRAY 1
#define BLACK 2
int n,M[N][N];
int color[N],d[N],f[N],tt;
void dfs_visit(int u){
     int v;
     color[u]=GRAY;
     d[u]=++tt;
     for(v=1;v<=n;v++)
     {
         if(M[u][v]==0)continue;
         if(color[v]==WHITE){
            dfs_visit(v);
         }
     }
     color[u]=BLACK;
         f[u]=++tt;
}
void dfs(){
     int u;
     for(u=1;u<=n;u++)color[u]=WHITE;
     tt=0;
     for(u=1;u<=n;u++)
     {
         if(color[u]==WHITE)dfs_visit(u);
     }
     for(u=1;u<=n;u++){
        printf("%d %d %d\n",u,d[u],f[u]);
     }
}
int main()
{
    int u,v,k,i,j;
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++)M[i][j]=0;
    }
    for(i=1;i<=n;i++)
    {
        scanf("%d%d",&u,&k);
        //u--;
        for(j=1;j<=k;j++)
        {
            scanf("%d",&v);
        //v--;
            M[u][v]=1;
        }
    }
    dfs();
    return 0;
}

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

int N, T = 0; 
vector<vector<int>> G(110);

vector<int> d(110, -1), f(110, -1);

void dfs(int v){
  T++; d[v] = T;
  for(int i=0; i<G[v].size(); i++){
    int u = G[v][i];

    if(d[u] == -1){
      //cout << v << " " << u << " " << T << endl;
      dfs(G[v][i]);
    }
  }
  T++;
  f[v] = T;
}

int main(){ 
  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;
      G[u-1].push_back(v-1);
    }
  }

  for(int i=0; i<N; i++){
    if(d[i] == -1) dfs(i);
  }
  
  for(int id=0; id<N; id++){
    cout << id+1 << " "<< d[id] << " " << f[id] << endl; 
  }
}

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

void dfs(int n, int &t, vector<vector<int>>& g, vector<int>& d, vector<int>& f, vector<bool>& seen)
{
    t++;
    if (d[n] == 0) d[n] = t;
    seen[n] = true;
    for (int i = 0; i < g[n].size(); i++)
    {
        if (seen[g[n][i]]) continue;
        dfs(g[n][i], t, g, d, f, seen);
    }
    t++;
    f[n] = t;
}

int main()
{
    int n; cin >> n;
    vector<vector<int>> g(n, vector<int>());
    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--;
            g[u].push_back(v);
        }
    } 
    vector<int> d(n, 0);
    vector<int> f(n, 0);
    vector<bool> seen(n, false);
    int t = 0;
    for (int i = 0; i < n; i++)
        if (seen[i] == false)
            dfs(i, t, g, d, f, seen);
    for (int i = 0; i < n; i++)
    {
        cout << i + 1 << " " <<  d[i] << " " << f[i] << endl;
    }
}

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

int n;
int t; //mytime?????????????????§???????´?
int mytime1[110],mytime2[110]; //?????§??????
int G[110][110];
int c[110];

void dfs(int cur){
	t+=1;
	mytime1[cur]=t;
	c[cur]=1;
	for(int dst=0; dst<n; ++dst){
		if(G[dst][cur]==1&&c[dst]==0){
			dfs(dst);
			t += 1;
		}
	} 
	mytime2[cur]=t;
}


int main()
{
	vector<int> v[110];
	cin>>n;
	for(int i=0;i<n;i++){
		int u,k;
		cin>>u>>k;
		for(int j=0;j<k;j++){
			int tmp;
			cin>>tmp;
			v[u].push_back(tmp);
		}
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			G[i][j]=0;
		}
	}
	for(int i=1;i<n+1;i++){
		for(int j=0;j<v[i].size();j++){
			G[i-1][v[i][j]-1]=1; //
		}
	}
	dfs(0);
	for(int i=0;i<n;i++){
		cout<<(i+1)<<' '<<mytime1[i]<<" "<<mytime2[i] <<endl;
	}
}