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) doesAllAdjsVisited(vertices []vertex) bool {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return false
		}
	}
	return true
}

func (v *vertex) isFirstVisit() bool {
	return v.firstVisitAt == 0
}

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

func (v *vertex) nextVertex(vertices []vertex) (vertexId, error) {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return vId, nil
		}
	}
	return vertexId(-1), fmt.Errorf("illegal")
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	timestamp = timestamp + 1
	currentVertex := &vertices[currentId-1]
	if currentVertex.isFirstVisit() {
		currentVertex.firstVisitAt = timestamp
	}
	for !currentVertex.doesAllAdjsVisited(vertices) {
		nextVertexId, _ := currentVertex.nextVertex(vertices)
		timestamp = dfs(nextVertexId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

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)
	}

	dfs(vertexId(1), 0, 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 <vector>
#include <stack>
using namespace std;
static const int MAX=101;
bool Visited[MAX]; //??\?????????????¢??????????
vector<int> Adjacency[MAX];
int dTime[MAX]; int fTime[MAX]; //?¢??????°??¶??´????¢?????????¶??´
void dfs(int j,int& clock)
{

    stack<int> S;
    S.push(j);dTime[j]=++clock;
    Visited[j]=true;
    while(!S.empty())
    {
        int p=S.top(); //???????????¶??????
        if(Adjacency[p].size()==0)
        {
            S.pop();
            fTime[p]=++clock;
            continue;
        }
        int i=0;
        if(Adjacency[p].size())
          while(Visited[Adjacency[p][i]]==true)
          {
            i++;
            if(i==Adjacency[p].size()) //???????°??????????????±?????????????
            {
                S.pop();
                fTime[p]=++clock;
                break;
            }
          }
        if(i==Adjacency[p].size()) continue;
        //if founded
        S.push(Adjacency[p][i]); dTime[Adjacency[p][i]]=++clock;
        Visited[Adjacency[p][i]]=true;
    }
}
int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++) Visited[i]=false;

    for(int i=1;i<=n;i++)
    {
        int p;cin>>p;
        int num;
        cin>>num;

        for(int j=0;j<num;j++)
        {
            int t;
            cin>>t;
            Adjacency[p].push_back(t);
        }
    }
    int clock=0;
    for(int i=1;i<=n;i++)  //???????????????????????°DFS?£?????????????
    {
        if(Visited[i]==false) dfs(i,clock);
    }
    for(int i=1;i<=n;i++)
        cout<<i<<' '<<dTime[i]<<' '<<fTime[i]<<endl;
}

C++: #include <iostream>
//#define int long long
//#define _DEBUG
#include <vector>
using namespace std;
int const infty = -1, none = -9;

//input
int N, T[107][107]; //T[i][j]:i->T[i][j]の辺

int /*D[107], */t, d[107], f[107];
bool visited[107];
void dfs(int cur){
    visited[cur] = true;
    d[cur] = t;
    t++;
    //cerr << "Visiting " << cur << " " << t << endl;
    for(int j=0; j<107; j++){
        if(T[cur][j]==none) break;
        if(!visited[T[cur][j]]/* || (D[T[cur][j]]!=infty || D[T[cur][j]]>D[cur])*/){
            //D[T[cur][j]] = D[cur]+1;
            dfs(T[cur][j]);
        }
    }
    f[cur] = t;
    t++;
}
void solve(){
    t = 1;
    //D[0] = 0;
    for(int i=0; i<N; i++){
        if(!visited[i]) dfs(i);
    }
}
void get(){
    cin >> N;
    //fill(D, D+N, infty);
    for(int i=0; i<N; i++){
        for(int j=0; j<N; j++){
            T[i][j] = none;
        }
    }

    for(int i=0; i<N; i++){
        int _i, k;
        cin >> _i >> k;
        for(int j=0; j<k; j++){
            int vj;
            cin >> vj;
            T[i][j] = vj-1;
        }
    }
    fill(visited, visited+N, false);
}

signed main(){
    get();
    solve();
    /*for(int i=0; i<N; i++){
        cout << i+1 << " " << D[i] << endl;
    }*/
    for(int i=0; i<N; i++){
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
}

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

using namespace std;

struct Node {
    bool visit = false;
    vector<int> next;
    int position = 0;
    int start;
    int end;
};

int main() {
    int n, id, k, temp, time = 1;
    Node node[101];
    stack<int> st;

    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> id >> k;
        for (int j = 0; j < k; j++) {
            cin >> temp;
            node[id].next.push_back(temp);
        }
    }

    node[1].start = time++;
    st.push(1);
    while (!st.empty()) {
        temp = st.top();
        if (node[temp].position < node[temp].next.size() && node[node[temp].next[node[temp].position]].visit == false) {
            node[node[temp].next[node[temp].position]].start = time++;
            st.push(node[temp].next[node[temp].position++]);
        }
        else {
            node[temp].visit = true;
            node[temp].end = time++;
            st.pop();
        }
    }

    for (int i = 1; i <= n; i++) {
        cout << i << " " << node[i].start << " " << node[i].end << endl;
    }

    return 0;
}

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

int discover(int &t, int node, int n, vector<vector<int>> &g, vector<int> &d, vector<int> &f);

int main()
{
	int n;
	cin >> n;
	vector<vector<int>> g(n+1);
	for (int i=1;i<=n;++i)
	{
		int u,k;
		cin >> u >> k;
		for (int j=0;j<k;++j)
		{
			int v;
			cin >> v;
			g[u].push_back(v);
		}
	}

	vector<int> d(n+1);
	vector<int> f(n+1);
	stack<int> st;

	for (int i=1;i<=n;++i)
	{
		d[i]=-1;
		f[i]=-1;
	}


	int t=0;
	for (int i=1;i<=n;++i)
	{
		if (d[i]<0)
		{
			d[i]=++t;
			discover(t,i,n,g,d,f);
			//f[i]=++t;
		}
	}

	for (int i=1;i<=n;++i)
	{
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
}


int discover(int &t, int node, int n, vector<vector<int>> &g, vector<int> &d, vector<int> &f)
{

	for (int i=0;i<g[node].size();++i)
	{
		int nn=g[node][i];
		if (d[nn]<0)
		{
			++t;
			d[nn]=t;
			discover(t,nn,n,g,d,f);
		}
	}

	++t;
	f[node]=t;

	return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define MAX 2000000000
#include <iostream>
#include <algorithm>
#include <stack>
using namespace std ;

int d[102] = { 0 }, f[102] = { 0 };
int M[102][102];

int main() {
	stack<int> stk;
	int n;
	cin >> n;
	for (int i = 1;i <= n;i++) {
		int k,l,m;
		cin >> m;
		cin >> k;
		for (int j = 0;j < k;j++) {
			cin >> l;
			M[m][l] = 1;
		}
	}
    
	stk.push(1);

    int i = 1,time=1;
    d[1]=1;
	while (!stk.empty()) {
		if (M[stk.top()][i] == 1 && d[i] == 0) {
			stk.push(i);
			time++;
			d[i] = time;
			i = 1;
		}
		else {
			i++;
			if (i > n) {
			    time++;
				f[stk.top()] = time;
				stk.pop();
				i=1;
			}
		}
	}

	for (int i = 1;i <= n;i++) {
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
  
}