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 <algorithm>
#include <iostream>
#include <math.h>
#include <stdio.h>
#include <string>
#include <sstream>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cmath>
 
using namespace std;

struct node{
	int id;
	queue<node*> adjacentNodeList;
};

int d[100] = {0};
int f[100] = {0};

int bfs(node* nd,int time){
	//cout<<nd->id<<" is called"<<endl;
	if(f[nd->id] != 0){
		return time;
	}
	if(d[nd->id] != 0){
		return time;
	}
	time = time + 1;
	if(d[nd->id] ==0){
		d[nd->id] = time;
	}
	while( !nd->adjacentNodeList.empty() ){
		if(nd->id == nd->adjacentNodeList.front()->id){
			nd->adjacentNodeList.pop();
		}else{
			time = bfs(nd->adjacentNodeList.front(),time);
			nd->adjacentNodeList.pop();
		}
	}
	time++;
	if( f[nd->id] == 0) f[nd->id] = time;
	return time;
}

int main()
{
	int n;
	cin>>n;
	struct node *nodeList = new node[n];
	for(int i = 0; i < n; i++){
		nodeList[i].id = i;
	}

	for(int i = 0; i < n;i++){
		int u,k;
		cin>>u>>k;
		u--;		//0 origin
		for(int j = 0; j < k; j++){
			int index;
			cin>>index;
			index--;		//0 origin
			nodeList[u].adjacentNodeList.push(&nodeList[index]);
		}
	}
	int time = 0;
	for(int i = 0; i < n; i++){
		time = bfs(&nodeList[i],time);	
	}

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

	return 0;
}

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

static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n,M[N][N];
int color[N], d[N], f[N], tt;
int nt[N];

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

void dfs_visit(int r){
    for(int i=0; i<n; i++) nt[i] = 0;

    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;
    
    while(!S.empty()){
        int u = S.top();
        int v = next(u);
        if(v!=-1){
            if(color[v]==WHITE){
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs(){
    for(int i=0; i<n; i++){
        color[i] = WHITE;
        nt[i] = 0;
    }
    tt = 0;
    for(int u=0; u<n; u++){
        if(color[u]==WHITE){
            dfs_visit(u);
        }
    }
    for(int i=0; i<n; i++){
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
}

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

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

void dfs(int& time,
    int start,
    const vector<vector<int>>& graph,
    vector<int>& arraialTimes,
    vector<int>& leftTimes,
    vector<bool>& checkList)
{
    stack<int> stack;
    stack.push(start);
    checkList[start] = true;
    arraialTimes[start] = ++time;
 
    while (!stack.empty())
    {
        int v = stack.top();
        int vSize = 0;
        for (int w : graph[v]) {
            if (!checkList[w]) {
                ++vSize;
                stack.push(w);
                checkList[w] = true;
                arraialTimes[w] = ++time;
                break;
            }
        }
        if (vSize == 0) {
            stack.pop();
            leftTimes[v] = ++time;
        }
    }
}

int main() {
    int n;
    cin >> n;
    vector<vector<int>> graph(n);
    vector<bool> checkList(n);
    vector<int> arrivalTimes(n);
    vector<int> leftTimes(n);


    graph.reserve(n);
    for (auto& g : graph) {
        int id;
        cin >> id;
        int size;
        cin >> size;
        for (int j = 0; j < size; ++j) {
            int k;
            cin >> k;
            g.push_back(k-1);
        }
    }
    int time = 0;
    for (int i = 0; i < n; ++i) {
        if (!checkList[i]) {
            dfs(time, i, graph, arrivalTimes, leftTimes, checkList);
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << i+ 1 << " " << arrivalTimes[i] << " " << leftTimes[i]<< endl;
    }

}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int d[maxx], f[maxx];
int flag[maxx];
int nowtime = 1;

void dfs(int u) {

    // 入栈时间
    flag[u] = 1;
    d[u] = nowtime++;
    for (int i = 1; i <= n; i++) {
        if (flag[i] == 0 && m[u][i] == 1) {
            dfs(i);
        }
    }
    //出栈时间
    f[u] = nowtime++;
}

int main()
{

    scanf("%d", &n);
    memset(m, 0, sizeof(m));
    memset(f, 0, sizeof(f));
    for (int i = 1; i <= n; i++) {
        scanf("%d %d", &u, &num);
        for (int j = 1; j <= num; j++) {
            scanf("%d", &v);
            m[u][v] = 1;
        }
    }
    for (int i = 1; i <= n; i++) {
        if(flag[i] == 0)
            dfs(i);
    }
    for (int i = 1; i <= n; i++) {
        printf("%d %d %d\n", i, d[i], f[i]);
    }
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int n,lis[111][111]={},d[111]={},f[111],t=1;

void dfs(int now){
  d[now]=t++;
  for(int i=1;i<=n;i++)
    if(lis[now][i]&&d[i]==0)dfs(i);
  f[now]=t++;
}

int main(){
  cin>>n;
  for(int c=0;c<n;c++){
    int u,k,v;
    cin>>u>>k;
    for(int i=0;i<k;i++){
      cin>>v;
      lis[u][v]=1;
    }
  }
  for(int i=1;i<=n;i++)if(d[i]==0)dfs(i);
  for(int i=1;i<=n;i++)cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;  
  
  return 0;
}