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<bits/stdc++.h>
using namespace std;

void get_network(int N,vector<vector<int>>& array){
    int u,k,x;

    for(int i=0;i<N;i++){
        cin>>u>>k;
        for(int j=0;j<k;j++){
            cin>>x;
            array[u-1][x-1]=1;
        }
    }

}

int dfs_rec(vector<int>& flag,int n,vector<vector<int>>& A,int v,vector<int>& f,vector<int>& d,int t){
        flag[v]=1;
        d[v]=t;
        for(int i=0;i<n;i++){
                if(A[v][i]==1 && flag[i]!=1){
                        t=dfs_rec(flag,n,A,i,f,d,t+1);

                }
        }
        f[v]=t+1;
        t++;
        return t;
}


int main(){
        cin.tie(0);
        ios::sync_with_stdio(false);

        int n;
        cin>>n;
        vector<vector<int>> array(n,vector<int>(n,0));
        get_network(n,array);

        //
        vector<int> flag(n,-1);
        vector<int> d(n,0);
        vector<int> f(n,0);
        //
        int t=0;
        t=dfs_rec(flag,n,array,0,f,d,t);
        for(int i=0;i<n;i++){
                if(flag[i]==-1){
                        t=dfs_rec(flag,n,array,i,f,d,t+1);
                }
        }
        //

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

        return 0;
}

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

int next(int u);
void dfs_visit(int r);
void dfs();

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;
		}
	}
	for(int i=0;i<n;i++){
		cin >> u >> k;
		u--;
		for(int j=0;j<k;j++){
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}
	
	dfs();
	return 0;
}

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

void dfs_visit(int r)
{
	for(int i=0;i<n;i++) nt[i] = 0;
	stack<int> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = ++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;
		nt[i] = 0;
	}
	tt = 0;
	for(int u=0;u<n;u++){
		if(color[u] == WHITE) dfs_visit(u);
	}
	for(int i=0;i<n;i++){
		cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
}

C++: # include <iostream>

using namespace std;

struct Vertex
{
    int id, k, *adjcent, start, end;
    bool passed = false;
};

Vertex *vertexs;
int time_ = 0;

void DFS(int now)
{
    vertexs[now].passed = true;
    time_++;
    vertexs[now].start = time_;
    for(int i=0; i<vertexs[now].k; i++)
    {
        if(!vertexs[vertexs[now].adjcent[i]].passed) DFS(vertexs[now].adjcent[i]);
    }
    time_++;
    vertexs[now].end = time_;
}

int main()
{
    int n;
    scanf("%d", &n);
    vertexs = new Vertex[n+1];
    for(int i=1; i<=n; i++)
    {
        scanf("%d%d", &vertexs[i].id, &vertexs[i].k);
        vertexs[i].adjcent = new int[vertexs[i].k];
        for(int j=0; j<vertexs[i].k; j++)
        {
            scanf("%d", &vertexs[i].adjcent[j]);
        }
    }
    for(int i=1; i<=n; i++)
    {
        if(!vertexs[i].passed) DFS(vertexs[i].id);
    }
    for(int i=1; i<=n; i++) printf("%d %d %d\n", vertexs[i].id, vertexs[i].start, vertexs[i].end);

    return 0;
}

C++: #include <iostream>
#define N 110

int t = 1;

int d[N], f[N];
int A[N][N];

void Depth(int id, int n){
  d[id] = t;
  t++;
  for(int i=1; i<=n; i++){
    if(A[id][i] == 1 && d[i] == 0){
      Depth(i, n);
    }
  }
  f[id] = t;
  t++;
}



int main(){
  for(int i=0; i<N; i++){
    d[i]=f[i]=0;
    for(int j=0; j<N; j++){
      A[i][j]=0;
    }
  }
  int n;
  std::cin >> n;
  for(int i=0; i<n; i++){
    int u, k, v;
    std::cin >> u >> k;
    for(int i=0; i<k; i++){
      std::cin >> v;
      A[u][v]=1;
    }
  }
  for(int i=1; i<=n; i++){
    if(d[i] == 0 && f[i] == 0){ Depth(i, n); }
  }
  for(int i=1; i<=n; i++){
    std::cout << i << " " << d[i] << " " << f[i] << std::endl;
  }

  return 0;
}

C++: #include<bits/stdc++.h>

using namespace std;

vector<int> G[110];

int timer;
int d[110],f[110];

bool used[110];

void dfs(int x)
{
    used[x]=true;
    d[x]=++timer;

    for(int i=0;i<G[x].size();i++)
    {
        if(!used[G[x][i]])
        {
            dfs(G[x][i]);
        }
    }

    f[x]=++timer;
}


int main()
{

    int n;

    cin>>n;

    for(int i=0;i<n;i++)
    {
        int a,b,c;

        cin>>a>>b;

        for(int i=0;i<b;i++)
        {
            cin>>c;

            G[a].push_back(c);
        }
    }

    timer=0;
    memset(used,0,sizeof(used));

    for(int i=1;i<=n;i++)
    {
        if(!used[i])
        {
            dfs(i);
        }
    }

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

    return 0;
}