Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve(parseProblem())
}

type graph struct {
	size  int
	edges [][]int
}

func parseProblem() *graph {
	n := scanInt(sc)
	g := &graph{
		size:  n,
		edges: make([][]int, n),
	}
	for i := 0; i < g.size; i++ {
		_ = scanInt(sc)
		k := scanInt(sc)
		g.edges[i] = make([]int, k)
		for j := 0; j < k; j++ {
			g.edges[i][j] = scanInt(sc) - 1
		}
	}
	return g
}

func resolve(g *graph) {
	ds := make([]int, g.size)
	fs := make([]int, g.size)
	time := 0
	for i := 0; i < len(ds); i++ {
		if ds[i] == 0 {
			time++
			time = _dfs(ds, fs, time, g, i)
		}
	}
	for i := 0; i < len(ds); i++ {
		fmt.Println(i+1, ds[i], fs[i])
	}
	return
}

func _dfs(ds, fs []int, time int, g *graph, idx int) int {
	ds[idx] = time
	for _, next := range g.edges[idx] {
		if ds[next] > 0 {
			continue
		}
		time++
		time = _dfs(ds, fs, time, g, next)
	}
	time++
	fs[idx] = time
	return time
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

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;
}

C++: #include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <cmath>
#include <iomanip>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <deque>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>



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();

}

C++: #include <iostream>
#include <iomanip>
#include <utility>
#include <cmath>
#include <random>
#include <vector>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <algorithm>
using namespace std;

#define rep(i,n) for(int i = 0; i<n; ++i)
#define REP(i,n) for(int i = 1; i<=n; ++i)
#define all(x) begin(x),end(x)
typedef long long ll;
typedef pair<int,int> ip;
typedef pair<ll,ll> lp;
const int inf = 1001001000;
const ll INF = 1LL<<60;
const int MOD = (int)1e9 + 7;

int t = 0;
vector<vector<int>> graph(110);
vector<ip> ans(110,make_pair(-1,-1));

void dfs(int index){
	if(ans[index].first==-1)ans[index].first = ++t;
	else return ;
	if(graph[index].size()==0){
		if(ans[index].second == -1){
			ans[index].second = ++t;
		}
		return;
	}
	rep(i,graph[index].size()){
		dfs(graph[index][i]);
	}
	if(ans[index].second == -1){
		ans[index].second = ++t;
	}
	return ;
}

int main(){
	int n;
	cin>>n;
	REP(i,n){
		int cnt;
		cin>>cnt>>cnt;
		vector<int> pp(cnt);
		rep(j,cnt){
			cin>>pp[j];
		}
		graph[i] = pp;
	}
	REP(i,n){
		if(ans[i].first==-1)dfs(i);
	}
	REP(i,n){
		cout<<i<<' '<<ans[i].first<<' '<<ans[i].second<<endl;
	}
	return 0;
}