Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveDfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: #include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <bitset>
#include <climits>
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RFOR(i,a,b) for (int i=(a)-1;i>=(b);i--)
#define ll long long
#define ull unsigned long long
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
const int INF = 1e9;
const int MOD = 1e9 + 7;

using namespace std;
int f_stamp[103];
int e_stamp[103];
vector<vector<int> > edge;
int t;
void dfs(int v){
	f_stamp[v] = ++t;
	REP(i,edge[v].size()){
		if(not f_stamp[edge[v][i]]){
			dfs(edge[v][i]);
		}
	}
	e_stamp[v] = ++t;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
	int n;
	cin>>n;
	edge.resize(n,vector<int>());
	REP(i,n){
		int v;cin>>v;v--;int t;cin>>t;
		while(t--){
			int u;cin>>u;u--;
			edge[v].push_back(u);
		}
	}
	REP(i,n){
		if(not f_stamp[i]){
			dfs(i);
		}
	}
	REP(i,n){
		cout << i+1 << ' ' << f_stamp[i] << ' ' << e_stamp[i] << endl;
	}
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define MAX 105

int n, G[MAX][MAX], d[MAX], f[MAX], Mytime;

void dfs(int r) {
	int nt[n + 1], st[n + 1], i;
	for (i = 1; i <= n; i++) {
		nt[i] = 1;
		st[i] = 0;
	}
	stack<int> S;
	S.push(r);
	d[r] = ++Mytime;
	st[r] = 1;
	while (!S.empty()) {
		int u = S.top();
		int v;
		for (v = nt[u]; v <= n; v++) {
			nt[u] = v + 1;
			if (G[u][v] && st[v] == 0) 
				break;
		}
		if (v <= n) {
			d[v] = ++Mytime;
			st[v] = 1;
			S.push(v);
		} else {
			S.pop();
			f[u] = ++Mytime;
		}
	}
}

int main(void) {
	int i, j, u, k, v;
	for (i = 0; i < MAX; i++) {
		d[i] = 0;
		f[i] = 0;
		for (j = 0; j < MAX; j++) {
			G[i][j] = 0;
		}
	}
	Mytime = 0;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> u >> k;
		for (j = 0; j < k; j++) {
			cin >> v;
			G[u][v] = 1;
		}
	}
	dfs(1);
	for (i = 1; i <= n; i++) {
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
}

C++: #include <vector>
#include <cmath>
#include <iostream>
#include <algorithm>

int n;
int time_count = 0;
std::vector<std::pair<int, int>> times;
std::vector<std::vector<int>> vec;

void dfs(int id) {
    if (times[id-1].first != -1) {
        return;
    }
    times[id-1].first = ++time_count; 
    auto l = vec[id];
    for (int i = 1; i <= n; i++) {
        if (id == i)
            continue;
        if (l[i] == 1)
            dfs(i);
    }
    times[id-1].second = ++time_count;
}

int main() {
    std::cin >> n;
    vec.assign(n+1, std::vector<int>(n+1, 0));
    for (int i = 0; i < n; i++) {
        times.push_back(std::make_pair(-1, -1));
    }
    for (int i = 0; i < n; i++) {
        int id, num, d;
        std::cin >> id >> num;
        for (int p = 0; p < num; p++) {
            std::cin >> d;
            vec[id][d] = 1;
        }
    }
    dfs(1);
    
    for (int i = 0; i < n; i++) {
        std::cout << i+1 << " " << times[i].first << " " << times[i].second << std::endl;
    }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <set>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <functional>
#include <map>
#include <cmath>
#include <stack>

using namespace std;

#define MAX 102

int main() {

    int d[MAX]={};
    int f[MAX]={};
    int graph[MAX][MAX]={};

    int n;scanf("%d",&n);

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

    stack<int> sta;
    int time=1;
    d[0]=time;
    sta.push(0);

    while(sta.size()>=1){
        time++;
        int v=sta.top();
        int nextV;
        bool isNothingConnect=true;
        for(int i=0;i<n;i++){
            if(graph[v][i]==1&&d[i]==0) {
                isNothingConnect = false;
                d[i] = time;
                nextV = i;
                break;
            }
        }

        if(isNothingConnect){
            f[v]=time;
            sta.pop();
        }else{
            sta.push(nextV);
        }

    }

    for(int i=0;i<n;i++){
        printf("%d %d %d\n",i+1, d[i], f[i]);
    }

    return 0;
}