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<stack>
using namespace std;
static const int N = 100; 
static const int WHITE = 0;
static const int GRAY = 1; 
static const int BLACK = 2;

int M[N][N], color[N], d[N], f[N], nt[N];
int tt,n;

int next(int u) {
	for(int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		return v;
	}
	return -1;
}

void dfs_visit(int u) {
	for(int i = 0; i < n; i++) nt[i] = 0;
	
	stack<int> S;
	S.push(u);
	color[u] = BLACK;
	d[u] = ++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; 
	}
	tt = 0; 
	
	for(int j = 0; j < n; j++) {
		if(color[j] == WHITE) {
			dfs_visit(j);
		}
	}
	
	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;
      }	
	}
	cin >> u >> k ;
	u--;
	for(int i = 0; i < k; i++ ) {
	   cin >> v;
	   v--;
	   M[u][v] = 1;	
	}	
	
	dfs();
	
	return 0;
}

C++: //Shunji Lin 08-144505

#include <iostream>

using namespace std;

bool adjmatrix[101][101]; //adjmatrix
int discover[101];
int processed[101];
int cur_time = 0;


void DFS(int vertex, int N) {
  cur_time++;
  discover[vertex] = cur_time; // set cost
  
  for (int i=1; i<= N; i++) {
    if(adjmatrix[vertex][i] && discover[i] == -1) {
      DFS(i, N);
    }
  }
  
  cur_time++;
  processed[vertex] = cur_time;
}


  
int main() {
  const int cur_time = 0;
  
  for (int i = 0; i < 101; i++) {
    discover[i] = -1; // upper limit
    processed[i] = -1;
  }
  int N;
  cin >> N;

  for (int i = 1; i <= N; i++) {
    int vertex, degree;
    cin >> vertex >> degree;

    for (int j = 0; j < degree; j++) {
      int outvertex;
      cin >> outvertex;
      adjmatrix[i][outvertex] = true;
    }
  }



  for (int i = 1; i <= N; i++) {
    if (discover[i] == -1) {
      DFS(i,N);
    }
  }

  for (int i = 1; i <=N; i++) {
    cout << i << " " << discover[i] << " "<< processed[i] << endl;
  }
}

C++: #include <iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;

static const int N=100;
static const int white=0;
static const int gray=1;
static const int black=2;
int color[N],nt[N];
int mp[N][N];
int n,d[N],f[N],tt;
int next(int r){
    
    for(int i=nt[r];i<n;i++){
        nt[r]=i+1;
        if(mp[r][i])return i;
        
    }
    return -1;
    
}

void dfs_visit(int r){
    rep(i,n){nt[i]=0;}
    stack<int> s;
    s.push(r);
    d[r]=++tt;
    color[r]=gray;
    while(!s.empty()){
        int u=s.top();
        int v=next(u);
        if(u!=-1){
            d[v]=++tt;
            color[v]=gray;
            s.push(v);
        }else{
            f[u]=++tt;
            color[u]=black;
            s.pop();
        }
        
        
        
    }
    
    
}



void dfs(){
    tt=0;
    rep(i,n){
        if(color[i]==white){
            dfs_visit(i);
        }
    }
    rep(i,n){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}


int main(){
    cin>>n;
    rep(i,N){
        rep(i,N){
            mp[i][n]=0;
        }
    }
    rep(i,n){
        int a,b;
        cin>>a>>b;
        a--;
        rep(i,b){
            int c;
            cin>>c;
            c--;
            mp[a][c]=1;
        }
    }
    dfs();
    return 0;
}

C++: #include<iostream>
#include<vector>
using namespace std;

std::vector<pair<int, int> > stamp(101);
std::vector<std::vector<int> > v(101);
bool isCheckd[101];
int cnt = 0;

void dfs(int k){
	cnt++;
	isCheckd[k] = true;
	stamp[k].first = cnt;
	for(int i=0;i<v[k].size();i++){
		int next = v[k][i];
		if(!isCheckd[next]){
			dfs(next);
		}
	}
	cnt++;
	stamp[k].second = cnt;
}

int main(){
	int n;

	fill(isCheckd,isCheckd+101,false);
	isCheckd[0] = true;
	cin >> n;

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

	dfs(1);

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

	return 0;
}

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

using namespace std;
int time = 0;

void dfs(int cur, vector<vector <int> > &list, vector<int> &d, vector<int> &f) {
		d[cur] =time;
		time +=1;
    for(int i = 0; i < list.size();i++){
      vector<int>::iterator it = list[cur].end();
	  vector<int>::iterator hoge = find(list[cur].begin(),list[cur].end(),i);
      if(d[i] == 0 && (hoge != it ) ){
        dfs(i,list,d,f);
      }
    }
    f[cur] = time;
    time +=1;
}

int main() {
  int np;
  int k,t,x;
  cin >> np ;
 
  vector <vector <int> > list(np);
  for(int i = 0;i<np;i++) {
    cin >> k;
    cin >> t;
    for(int j = 0; j < t ;j++) {
      cin >>x;
      list[k-1].push_back(x-1);
    }
  }
  vector <int> d(np,0);
  vector <int> f(np,0);
  dfs(0,list,d,f);
  for(int i = 0;i < np; i++){
    cout << i+1 <<" "<<d[i]+1 <<" "<<f[i]+1<<endl;
  }


  return 0;
}