Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

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

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

C++: #include <iostream>
#include <stack>
using namespace std;
#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
int color[MAX],d[MAX],f[MAX];
int n,t;
int N[MAX][MAX];
void dfs(int u){
    color[u] = GRAY;
    d[u] = ++t;
    for(int v=0;v<n;v++){
        if(N[u][v]!=0&&color[v]==WHITE){
            dfs(v);
        }
    }
    color[u] = BLACK;
    f[u] = ++t;
}
void dfs_init(){
    t = 0;
    for(int i=0;i<n;i++){
        color[i] = WHITE;
    }
    for(int i=0;i<n;i++){
        if(color[i]==WHITE)
            dfs(i);
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<d[i]<<" " <<f[i]<<endl;
    }
}
int main()
{
    cin>>n;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            N[i][j] = 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;
            N[i][v-1] = 1;
        }
    }
    dfs_init();
    return 0;
}

C++: #include<iostream>
int main(){

  int n,a;
  std::cin>>n;

  int Adj[100][100],adj[100][100]={0},find[100][2],back[100][100],depth[100]={0},endflag[100]={0},flag;
	int u[n],k[n],kcou=0,timenow=0,v,pred,prev,firstv,backcount[100]={0},flag1=0;
  for(int i=0;i<n;i++){
    std::cin>>u[i];
    std::cin>>k[i];
    for(int j=0;j<k[i];j++){
      std::cin>>Adj[i][j];
    }
  }
	
	/*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    	std::cout<<Adj[i][j]<<" ";
    }
  	std::cout<<"\n";
  }*/
	
	v=0;
	firstv=0;
	while(timenow<n*2){
		flag=0;
		if(find[firstv][0]!=NULL&&find[firstv][1]!=NULL){
			for(int i=0;i<n;i++){
				if(find[i][0]==NULL){
					//std::cout<<i<<"\n";
					firstv=i;
					v=i;
					break;
				}
			}
		}
		
		// std::cout<<"v="<<v+1<<" ";
		//std::cout<<find[v][0]<<" "<<find[v][1];
		// std::cout<<" endflag="<<endflag[v]<<" ";
		if(find[v][0]==NULL){
			timenow++;
			find[v][0]=timenow;
			// std::cout<<v+1<<"[0]= '"<<timenow<<"' ";
			flag=1;
			//std::cout<<flag<<" 1";
		}else if(find[v][1]==NULL){
			if(endflag[v]==1){
				if(backcount[v]<=1){
				timenow++;
				find[v][1]=timenow;
				// std::cout<<v+1<<"[1]= '"<<timenow<<"' ";
				}
				flag=2;
			}
			//std::cout<<flag;
		}else{
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			flag=3;
			//std::cout<<flag<<" 0";
		}

		if(flag==0){
				pred=depth[v];
				depth[v]++;
				prev=v;
				v=Adj[v][pred]-1;
				back[v][backcount[v]]=prev;
				backcount[v]++;
				//std::cout<<flag<<"\n";
		}else if(flag==1){
			if(endflag[v]==0){
				if(Adj[v][depth[v]]-1!=v){
					while(find[Adj[v][depth[v]]-1][0]!=NULL && k[v]-1!=depth[v]){
						depth[v]++;
					}
					if(find[Adj[v][depth[v]]-1][0]==NULL){
						pred=depth[v];
						depth[v]++;
						prev=v;
						v=Adj[v][pred]-1;
						back[v][backcount[v]]=prev;
						backcount[v]++;
					}else{
						depth[v]++;
					}
				}else{
					pred=depth[v];
					depth[v]++;
				}
			}
		}else if(flag==2){
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			//std::cout<<flag<<"\n";
		}
		if(depth[v]>k[v]-1){
			endflag[v]=1;
		}
		// std::cout<<"flag="<<flag<<"\n";
	}
	
	
	
	
  for(int i=0;i<n;i++){
     std::cout<<i+1<<" "<<find[i][0]<<" ";
     std::cout<<find[i][1]<<"\n";
    //std::cout<<"\n";
  }

  return 0;
}

C++: #include <iostream>
using namespace std;
struct id{
    int c[101];
    int d=0;
    int f=0;
    int u=0;
};
int n,t=0;
id a[101];
void time(int e){
    if(a[e].u==0){
        a[e].u++;
        a[e].d=++t;
        for(int i=1;i<=n;i++){
            if(a[e].c[i]==1){
                time(i);
            }
        }
        a[e].f=++t;
    }
}
int main(){
    int x,y,z;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>x>>y;
        for(int j=0;j<y;j++){
            cin>>z;
            a[x].c[z]=1;
        }
    }
    for(int i=1;i<=n;i++){
        if(a[i].u==0){
            time(i);
        }
    }
    for(int i=1;i<=n;i++){
        cout<<i<<" "<<a[i].d<<" "<<a[i].f<<endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#include <iostream>
#include <math.h>
using namespace std;
using Graph = vector<int>;
vector<Graph>g;
vector<int> d;
vector<int> f;
int t = 0;
void dfs(int i) {
    Graph G = g[i];
    if (d[i] != 0) {
        return;
    }

    t++;
    d[i] = t;
    for (int j=0; j < G.size(); j++) {
        dfs(G[j]);
    }

    t++;
    f[i] = t;
}

int main() {
    int G;
    cin >> G;
    g.resize(G);
    d.resize(G);
    f.resize(G);

    for (int i=0; i < G; i++) {
        int num, c;
        cin >> num >> c;
        for (int j=0; j<c; j++) {
            int k;
            cin >> k;
            g[num-1].emplace_back(k-1);
        }
    }

    dfs(0);
    for (int i=0; i < G; i++) {
        if (d[i] == 0) {
            dfs(i);
        }
    }

    for (int i=0; i < G; i++) {
        int start_time = d[i];
        int end_time = f[i];
        cout << i+1 << " " << start_time << " " << end_time << endl;
    }

    return 0;
}