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
//------------------------------------------
#include <bits/stdc++.h>
//DEFINE
//------------------------------------------
#define ll long long
#define ld long double
#define ALLv(a)  (a).begin(),(a).end()
#define ALL(a,n)  (a),(a)+n
#define vi vector<long long>
#define vd vector<long double>
#define vs vector<string>
#define dcml(n) fixed<<setprecision(n)
//CONST
//------------------------------------------
const ll INF=1010000000000000017LL;
const ll MOD=1000000007LL;
const ld EPS=1e-12;
const ld PI=3.14159265358979323846;
//REPEAT
//------------------------------------------
#define   FOR(i,m,n) for(ll (i)=(m);   (i)<(n);  (i)++)
#define  FORS(i,m,n) for(ll (i)=(m);   (i)<=(n); (i)++)
#define  RFOR(i,m,n) for(ll (i)=(n)-1; (i)>=(n); (i)--)
#define RFORS(i,m,n) for(ll (i)=(n);   (i)>(n);  (i)--)
#define   REP(i,n)   for(ll (i)=0;     (i)<(n);  (i)++)
#define  REPS(i,x)   for(ll (i)=1;     (i)<=(x); (i)++)
#define  RREP(i,x)   for(ll (i)=(x)-1; (i)>=0;   (i)--)
#define RREPS(i,x)   for(ll (i)=(x);   (i)> 0;   (i)--)
#define  WREP(i,in,j,jn) REP(i,in)REP(j,jn)
#define WREPS(i,in,j,jn) REPS(i,in)REPS(j,jn)
//-----------------------------------------
//namespace
using namespace std;
//ライブラリはここに
//↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

//-----------------------------------------
vector<ll> G[110];
bool done[110];
ll START[110],END[110];
ll t=1;
void dfs(ll from){
    done[from]=true;
    if(START[from]==-1) START[from]=t++;
    for(auto r:G[from]){
        if(done[r])continue;
        dfs(r);
    }
    if(END[from]==-1) END[from]=t++;
}
int main(void){
    ll N;cin>>N;
    REP(i,N){
        START[i]=END[i]=-1;
        done[i]=false;
    }
    REP(i,N){
        ll idx;cin>>idx;ll k;cin>>k;
        REP(j,k){
            ll to;cin>>to;to--;
            G[i].push_back(to);
        }
    }
    REP(i,N) dfs(i);
    REP(i,N){
        printf("%lld %lld %lld\n",i+1,START[i],END[i]);
    }
}

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

typedef long long ll;

vector<vector<ll>> graph(100);
vector<bool> visit(100,false);
vector<ll> d(100);
vector<ll> f(100);
ll tmp = 0;

void dfs(ll v)
{
    ll i;
    visit.at(v) = true;
    d.at(v) = ++tmp;
    for(i = 0;i < graph.at(v).size();++i){
        ll g = graph.at(v).at(i);
        if(visit.at(g)){
            continue;
        }
        dfs(g);
    }
    f.at(v) = ++tmp;
    return;
}

int main()
{
    ll i,j;
    ll n;
    cin >> n;
    for(i = 0;i < n;++i){
        ll u,k;
        cin >> u >> k;
        for(j = 0;j < k;++j){
            ll v;
            cin >> v;
            graph.at(u-1).push_back(v-1);
        }
    }
    for(i = 0;i < n;++i){
        if(!visit.at(i)){
            dfs(i);
        }
    }
    for(i = 0;i < n;++i){
        cout << i+1 << " " << d.at(i) << " " << f.at(i) << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<stack>
#include<vector>
#include<string>
#include<algorithm>

struct node {
	int num;
	std::vector<int> child;
};

int recurcive(node nodes[],int d[100], int f[100], int n, int count) {
	d[n] = count++;
	for (size_t i = 0; i < nodes[n].child.size(); i++) {
		if (d[nodes[n].child[i]] == 0) {
			count = recurcive(nodes, d, f, nodes[n].child[i], count);
		} else {
			nodes[n].child.erase(std::find(nodes[n].child.begin(), nodes[n].child.end(), nodes[n].child[i]));
			i--;
		}
	}
	f[n] = count++;

	return count;
}

int main() {
	int node_num;
	node nodes[100];
	std::cin >> node_num;

	for (int i = 0; i < node_num; i++) {
		int n, num;
		std::cin >> n >> num;
		for (int j = 0; j < num; j++) {
			int val;
			std::cin >> val;
			nodes[n - 1].child.push_back(val - 1);
		}
	}

	std::stack<int> st, st2;
	std::vector<int> gone;
	int d[100], f[100];
	int count = 1;

	for (int i = 0; i < 100; i++)
		d[i] = f[i] = 0;

	for (int i = 0; i < node_num; i++) {
		if (d[i] == 0) {
			count = recurcive(nodes, d, f, i, count);
		}
	}

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

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

int times;
vector<vector<int> > lists;
vector<int> stampA;
vector<int> stampB;

void dfs(int point){
    times++;
    stampA.at(point-1)=times;
    for(int i=0;i<(int)lists.at(point-1).size();i++){
        if(stampA.at(lists.at(point-1).at(i)-1)==0) dfs(lists.at(point-1).at(i));
    }
    times++;
    stampB.at(point-1)=times;
    
}

int main(){
    times=0;
    int n;
    cin >> n;
    lists.resize(n,vector<int>());
    stampA.resize(n,0);
    stampB.resize(n,0);
    for(int i=0;i<n;i++){
        int u,k;
        cin >> u >> k;
        for(int j=0;j<k;j++){
            int v;
            cin >> v;
            lists.at(u-1).push_back(v);
        }
    }
    
    for(int i=0;i<n;i++){
        if(stampA.at(i)==0) dfs(i+1);
    }
    
    for(int i=0;i<n;i++){
        cout << i+1 << " " << stampA.at(i) << " " << stampB.at(i) << endl;
    }
}

C++: #include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int a[101][101],start[101],end[101],n,p=0,v[101];
void dfs(int u){
    if(!v[u]){v[u]++;
    start[u]=++p;
    r(i,1,n+1)if(a[u][i])dfs(i);
    end[u]=++p;}
}
int main(){
    int q,qq,qqq;
    cin>>n;
    r(i,0,n){cin>>q>>qq;
        r(i,0,qq){cin>>qqq;
            a[q][qqq]++;
        }
    }
    r(i,1,n+1)if(!v[i])dfs(i);
    r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}