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
	for {
		startNode := findStartNode(childrenMap, timeRecordMap)
		if startNode > 0 {
			visit(startNode, &timer, childrenMap, timeRecordMap)
		} else {
			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
		}
	}
	if x < 0 {
		return -1
	}

	found := false
	i := 0
	for i < len(childrenMap) {
		children := childrenMap[i]
		for j := 0; j < len(children); j++ {
			if children[j] == x {
				x = j + 1
				found = true
				break
			}
		}
		if found {
			i = 0
		} else {
			i++
		}
	}
	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 100
#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=0;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=0;u<n;u++) color[u] =WHITE;
  tt=0;

  for(u=0;u<n;u++){
    if(color[u] == WHITE) dfs_visit(u);
  }
  for(u=0;u<n;u++){
    printf("%d %d %d\n",u+1,d[u],f[u]);
  }
}

int main(){
  int u,v,k,i,j;

  scanf("%d",&n);
  for(i=0;i<n;i++){
    for(j=0;j<n;j++) M[i][j] = 0;
  }

  for(i=0;i<n;i++){
    scanf("%d %d",&u,&k);
    u--;
    for(j=0;j<k;j++){
      scanf("%d",&v);
      v--;
      M[u][v] = 1;
    }
  }
  dfs();

  return 0;
}

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

enum Status {WHITE, GRAY, BLACK};

stack<int> stc;
Status *status;
int *discovered, *finished;
bool *visited;
vector<vector<int> > a;
int n, timer;

void dfs(int i){
        if(status[i]==BLACK) return;
        if(status[i]==WHITE){
                discovered[i] = ++timer;
                status[i] = GRAY;
        }

        if(visited[i]) return;
        visited[i] = true;
        stc.push(i);

        for(int j=0;j<a[i].size();j++) dfs(a[i][j]);

        if(status[i]==GRAY){
                finished[i] = ++timer;
                status[i] = BLACK;
        }
        stc.pop();
}

int main(){

        cin>>n;
        a = vector<vector<int> >(n, vector<int>());
        status = new Status[n];
        discovered = new int[n];
        finished = new int[n];
        visited = new bool[n];

        int m, k, r;
        for(int i=0;i<n;i++){
                cin>>r;
                cin>>m;
                for(int j=0;j<m;j++){
                        cin>>k;
                        a[r-1].emplace_back(k-1);
                }
        }
        for(int i=0;i<n;i++) status[i] = WHITE;
        for(int i=0;i<n;i++) visited[i] = false;

        timer = 0;
        for(int i=0;i<n;i++)
                dfs(i);

        for(int i=0;i<n;i++){
                cout<<i+1<<" "<<discovered[i]<<" "<<finished[i]<<endl;
        }
        return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
int main()
{
    int n, ti = 0;
    scanf("%d", &n);
    vector<vector<int>> a(n);
    vector<int> vis(n, 0), lea(n, 0), sea(n, 0);
    for (int i = 0, u, k; i < n; i++)
    {
        scanf("%d %d", &u, &k);
        u--;
        for (int j = 0, v; j < k; j++)
        {
            scanf("%d", &v);
            v--;
            a[u].push_back(v);
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (!vis[i])
        {
            stack<int> b;
            b.push(i);
            for (int t; !b.empty(); )
            {
                t = b.top();
                if (!vis[t])
                {
                    vis[t] = ++ti;
                }
                for (; sea[t] < a[t].size(); sea[t]++)
                {
                    if (!vis[a[t][sea[t]]])
                    {
                        b.push(a[t][sea[t]]);
                        break;
                    }
                }
                if (sea[t] >= a[t].size())
                {
                    b.pop();
                    lea[t] = ++ti;
                }
            }
        }
    }
    for (int i = 0; i < n; i++)
    {
        printf("%d %d %d\n", i + 1, vis[i], lea[i]);
    }
}

C++: #include<iostream>
int main(){

  int n,a;
  std::cin>>n;

  int Adj[100][100],adj[100][100]={0},find[100][2],back[100][100],depth[100]={0},endflag[100]={0},flag;
	int u[n],k[n],kcou=0,timenow=0,v,pred,prev,firstv,backcount[100]={0},flag1=0;
  for(int i=0;i<n;i++){
    std::cin>>u[i];
    std::cin>>k[i];
    for(int j=0;j<k[i];j++){
      std::cin>>Adj[i][j];
    }
  }
	
	/*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    	std::cout<<Adj[i][j]<<" ";
    }
  	std::cout<<"\n";
  }*/
	
	v=0;
	firstv=0;
	while(timenow<n*2){
		flag=0;
		if(find[firstv][0]!=NULL&&find[firstv][1]!=NULL){
			for(int i=0;i<n;i++){
				if(find[i][0]==NULL){
					//std::cout<<i<<"\n";
					firstv=i;
					v=i;
					break;
				}
			}
		}
		
		// std::cout<<"v="<<v+1<<" ";
		//std::cout<<find[v][0]<<" "<<find[v][1];
		
		if(find[v][0]==NULL){
			timenow++;
			find[v][0]=timenow;
			// std::cout<<" '"<<timenow<<"' \n";
			flag=1;
			//std::cout<<flag<<" 1";
		}else if(find[v][1]==NULL){
			if(v==7){
				//std::cout<<endflag[v];
				//std::cout<<backcount[v];
			}
			if(endflag[v]==1){
				if(backcount[v]<=1){
				timenow++;
				find[v][1]=timenow;
				// std::cout<<" '"<<timenow<<"' \n";
				}
				flag=2;
			}
			//std::cout<<flag<<" 2";
		}else{
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			flag=3;
			//std::cout<<flag<<" 0";
		}

		if(flag==0){
			pred=depth[v];
			depth[v]++;
			prev=v;
			v=Adj[v][pred]-1;
			back[v][backcount[v]]=prev;
			backcount[v]++;
			//std::cout<<flag<<"\n";
		}else if(flag==1){
			if(endflag[v]==0){
				flag1=0;
				if(Adj[v][depth[v]]-1!=v){
					//std::cout<<"flag1="<<flag1<<"\n";
					if(find[Adj[v][pred]-1][0]==NULL){
						pred=depth[v];
						depth[v]++;
						prev=v;
						v=Adj[v][pred]-1;
						back[v][backcount[v]]=prev;
						backcount[v]++;
					}else{
						depth[v]++;
					}
				}else{
					pred=depth[v];
					depth[v]++;
				}
			}
		}else if(flag==2){
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			//std::cout<<flag<<"\n";
		}
		if(depth[v]>k[v]-1){
			endflag[v]=1;
		}
		// std::cout<<"flag="<<flag<<"\n";
	}
	
	
	
	
  for(int i=0;i<n;i++){
     std::cout<<i+1<<" "<<find[i][0]<<" ";
     std::cout<<find[i][1]<<"\n";
    //std::cout<<"\n";
  }

  return 0;
}