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 <iostream>
#include <string>
#include <sstream>
#include <list>
#include <stack>
#include <queue>
#include <algorithm>
#include <utility>
#include <vector>
#include <map>
#include <bitset>
#include <cstring>
#include <cstdio>
#include <cmath>

using namespace std;

struct dd{
    int d,f;
    dd(){
        d=0;
        f=0;
    }
};
bool data[101][101]={};
void f1(dd*,int,int&,int);

int main()
{
    int N,M,num1,num2;
    dd ddata[101]={};
    cin>>N;
    for(int i=0;i<N;i++){
        cin>>num1;
        cin>>M;
        for(int j=0;j<M;j++){
            cin>>num2;
            data[num1][num2]=true;
        }
    }
    int time=1;
    f1(ddata,1,time,N);
    for(int i=1;i<=N;i++){
        cout<<i<<' '<<ddata[i].d;
        if(ddata[i].d){
            cout<<' '<<ddata[i].f;
        }
        cout<<endl;
    }
}
void f1(dd* ddata,int num,int& time,int N)
{
    if(!ddata[num].d)ddata[num].d=time++;
    data[num][num]=false;
    for(int i=1;i<=N;i++){
        if(data[num][i]){
            data[num][i]=false;
            f1(ddata,i,time,N);
        }
    }
    if(!ddata[num].f)ddata[num].f=time++;
}

C++: #include<iostream>
#include<vector>
#include<queue>

using namespace std;

vector<vector<int>> adjacent;
vector<pair<int, int>> ans;
vector<bool>checked;

//?????????is????????????
int dfs(int now,int time = 1) {
	cout << now << endl;
	ans[now].first = time;
	checked[now] = true;
	for (int i = 0; i < adjacent[now].size(); i++) {
		if (!checked[adjacent[now][i]]) {
			time = dfs(adjacent[now][i], time + 1);
		}
	}
	ans[now].second = time+1;
	return time + 1;
}

int main() {
	int n;
	cin >> n;
	adjacent = vector<vector<int>>(n);
	checked = vector<bool>(n, false);
	ans.resize(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;
			adjacent[u - 1].push_back(v-1);
		}
	}

	dfs(0, 1);
	
	for (int i = 0; i < n; i++) {
		cout << i + 1 << " " << ans[i].first << " " << ans[i].second << endl;
	}

}

C++: #include<iostream>
#include<stack>
#include<string.h>
using namespace std;
//void haichi(int);
int MA[101][101];
int n,cnt=1,Flag;
int id[101],d[101],f[101];
stack<int> S;
int main(void){
	int u,k,v;
	memset(MA,0,sizeof(MA));
	for(int i=1;i<=100;i++){
		id[i] = 0;
		d[i] = 0;
		f[i] = 0;
	}
	cin >> n;
	for(int i=0;i<n;i++){
		cin >> u >> k;
		for(int j=0;j<k;j++){
			cin >> v;
			MA[u][v]=1;
		}
	}
	S.push(1);
	d[1] = 1;
	while(!S.empty()){
		Flag=0;
		/*if(d[S.top()] == 0)
			d[S.top()]=cnt;*/
		cnt++;
		for(int i=1;i<=n;i++){  //i=S.top();
			if(MA[S.top()][i]==1 && d[i] == 0){
				MA[S.top()][i]=0;
				S.push(i);
				//cout << "PUSH " << S.top() << endl;;
				d[S.top()]=cnt;
				Flag=1;
				break;
			}
		}
		if(Flag==0){
			//cout << "POP " << S.top() << endl;
			if(f[S.top()]==0) f[S.top()] = cnt;
			S.pop();
		}
	}
	for(int i=1;i<=n;i++){
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include<iostream>
using namespace std;
int map[101][101];
int all = 0;
int start[101];
int end_2[101];
int n;
void dps(int k) {
	start[k] = ++all;
	for (int i = 1; i <= n; i++) {
		if (map[k][i] && start[i] == 0) {
			dps(i);
		}
	}
	end_2[k] = ++all;
}
int main(void) {
	cin >> n;
	for (int i = 0; i < n; i++) {
		int a;
		cin >> a;
		int m;
		cin >> m;
		for (int j = 0; j < m; j++) {
			int b;
			cin >> b;
			map[a][b] = 1;
		}
	}
	for (int i = 1; i <= n; i++) {
		if (start[i] == 0) {
			dps(i);
		}
	}
	for (int i = 1; i <= n; i++) {
		cout << i << " " << start[i] <<" "<< end_2[i]<<endl;
	}
}

C++: #if 0

#endif

#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[cur][dst]==1&&c[dst]==0){
			dfs(dst);
		}
	} 
	t += 1;
	mytime2[cur]=t;
}


int main()
{
	int G[110][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;
			G[u][tmp]=1;
		}
	}
	
	for(int i=0;i<n;++i){
		dfs(i);
		cout<<(i+1)<<' '<<mytime1[i+1]<<" "<<mytime2[i+1] <<endl;
	}
}

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

vector<int> ans1; //訪れた時間を格納する
vector<int> ans2; //再び訪れた時間

int t = 0;

void dfs(Graph &G, int v = 0){ //vは現在の頂点
    t++;
    ans1.at(v) = t; //行くときに時間を記録する
    for(auto nv: G.at(v)){
        if(ans1.at(nv)) continue; //一回以上訪れたなら行かない
        dfs(G, nv);
    }
    t++;
    ans2.at(v) = t;
}

int main(){
    int n; cin >> n;
    Graph G(n); //以下0-indexed
    ans1.resize(n);
    ans2.resize(n);
    for(int i = 0; i < n; i++){ //グラフを隣接リストとして入力
        int a, b; cin >> a >> b;
        for(int j = 0; j < b; j++){
            int k; cin >> k; k--;
            G.at(i).push_back(k);
        }
    }
    for(int i = 0; i < n; i++){
        if(ans1.at(i) == 0) dfs(G, i);
    }
    for(int i = 0; i < n; i++){ //答えの出力
        cout << i+1 << " " << ans1.at(i) << " " << ans2.at(i) << endl;
    }
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;

constexpr int LEN = 105;
bool ga[LEN][LEN];
int d[LEN], f[LEN];

int dfs(int id, int time, const int n){
	int	t = ++time;
	if(d[id] < 0) d[id] = t;
	rep(i, n)
		if(ga[id][i] && (d[i] < 0)) t = dfs(i, t, n);
	if(f[id] < 0) f[id] = ++t;

	return t;
}

int main(){
	memset(d, -1, LEN*sizeof(int));
	memset(f, -1, LEN*sizeof(int));
	memset(ga, 0, LEN*LEN*sizeof(bool));
	int n; cin >> n;
	rep(i, n){
		int u, k; cin >> u >> k;
		rep(j, k){
			int v; cin >> v;
			ga[u-1][v-1] = 1;
		}
	}

	int t = 0;
	rep(id, n) if(d[id] < 0) t = dfs(id, t, n);
	rep(i, n) cout << i+1 << ' ' << d[i] << ' ' << f[i] << endl;

	return 0;
}