Go: package main

import "fmt"

type node struct {
	id, d, v int
	adj      []node
}

var n int
var seen []bool
var graph []node

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func dfs(v, t int) int {
	// fmt.Printf("dfs(v %d, t %d) en:\n", v, t)
	seen[v] = true
	graph[v].v = t
	tt := t
	for _, vv := range graph[v].adj {
		if !seen[vv.id] {
			tt = max(tt, dfs(vv.id, tt+1))
		}
	}
	graph[v].d = tt + 1
	// fmt.Printf("dfs(v %d, t %d) ex: d %d\n", v, t, graph[v].d)
	return graph[v].d
}

func main() {
	fmt.Scan(&n)
	graph = make([]node, n+1)
	for i := 1; i <= n; i++ {
		var u, k, v int
		fmt.Scan(&u, &k)
		graph[u].id = u
		// 頂点uはk個の隣接頂点を持っている
		for j := 0; j < k; j++ {
			fmt.Scan(&v)
			var t node
			t.id = v
			graph[u].adj = append(graph[u].adj, t)
		}
	}
	// fmt.Println("n", n, "graph", graph)
	seen = make([]bool, n+1)
	// t := dfs(1, 1)
	v, t := 1, 1
	done := false
	for !done {
		tt := dfs(v, t)
		done = true
		for i := range seen {
			if !seen[i] {
				done = false
				v = graph[i].id
				t = tt
				break
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, graph[i].v, graph[i].d)
	}
}

C++: #include <iostream>

constexpr int MAXN = 100;
int V[MAXN][MAXN];
int D[MAXN];
int F[MAXN];

template<int STACK_SIZE, typename T = int>
class Stack {

public:
    Stack() {};

    void Push(T val) {
        if (top_ < STACK_SIZE) {
            stack_[top_++] = val;
        }else{
            std::cerr << "Stack over flow..." << std::endl;
            exit(-11);
        }
    };
    bool Pop() {
        if (top_ > 0) {
            stack_[--top_];
            return true;
        }
        return false;
    };

    T Top() {
        return stack_[top_ - 1];
    }

    int Size() {return top_;}


private:
    int max_size_ = STACK_SIZE;
    int top_ = 0;
    T stack_[STACK_SIZE];
};

Stack<MAXN, int> S;

int main() {

    int n;
    std::cin >> n;

    for (int i = 0; i < n; i++) {
        int id, e_num;
        std::cin >> id >> e_num;
        for (int j = 0; j < e_num; j++) {
            int t;
            std::cin >> t;
            V[id - 1][t - 1] = 1;
        }
    }
    int cnt = 0;
    for (int t = 0; t < n; t++) {
        if (D[t] == 0) {
            D[t] = ++cnt;
            S.Push(t);
            while (S.Size()) {
                for (int i = 0; i < n; i++) {
                    if ((V[S.Top()][i] == 1) && (D[i] == 0)) {
                        S.Push(i);
                        D[i] = ++cnt;
                        break;
                    }
                    if (i == n - 1) {
                        F[S.Top()] = ++cnt;
                        S.Pop();
                    }
                }
            }
        }
    }

    for (int i = 0; i < n; i++) {
        std::cout << i + 1 << " " << D[i] << " " << F[i] << std::endl;
    }

}

C++: #include <iostream>
#include <vector>
#include <list>
#include <cstdlib>

const int MAX_N = 100;

struct Node {
  int v;
  int firstVisitedTime;
  int lastVisitedTime;
  bool visited;
  bool opened;
};

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

  int n = 0;
  std::cin >> n;

  std::vector<std::list<int> *> *graph = new std::vector<std::list<int> *>(n + 1);
  std::vector<struct Node *> *nodes = new std::vector<struct Node *>(n + 1);
  
  for (int i = 1; i <= n; i++) {
    int v = 0;
    std::cin >> v;

    int k = 0;
    std::cin >> k;

    std::list<int> *neighbors = new std::list<int>();

    for (int j = 0; j < k; j++) {
      int a = 0;
      std::cin >> a;

      neighbors->push_back(a);
    }

    graph->at(i) = neighbors;

    struct Node *node = (struct Node *) std::malloc(sizeof(struct Node));

    node->v = i;
    node->firstVisitedTime = 0;
    node->lastVisitedTime = 0;
    node->visited = false;
    node->opened = false;
    
    nodes->at(i) = node;
  }
  
  std::list<int> *stack = new std::list<int>();

  int start = 1;
  
  stack->push_front(start);
  
  nodes->at(start)->firstVisitedTime = 1;
  nodes->at(start)->lastVisitedTime = 1;

  int count = 0;

  while (!stack->empty()) {
    count++;
    
    int n = stack->front();
    struct Node *node = nodes->at(n);

    if ((node->visited) && (!node->opened)) {
      count--;
    }
    
    if (!node->visited) {
      node->firstVisitedTime = count;
      node->visited = true;
    }
    
    //std::cout << count << " = " << n << std::endl;
    
    if (node->opened) {
      node->lastVisitedTime = count;
       
      stack->pop_front();
      
      continue;
    }
    
    std::list<int> *neighbors = graph->at(n);

    while (!neighbors->empty()) {
      int v = neighbors->front();
      neighbors->pop_front();

      if (!nodes->at(v)->visited) {
	stack->push_front(v);

	break;
      }
    }

    if (neighbors->empty()) {
      node->opened = true;
    }
  }

  for (std::vector<struct Node *>::iterator iterator = nodes->begin() + 1; iterator != nodes->end(); ++iterator) {
    struct Node *node = *iterator;
        
    std::cout << node->v << " " << node->firstVisitedTime << " " << node->lastVisitedTime << std::endl;
  }
  
  return 0;
}

C++: #include<stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
void depth_search(int);
void depth();
int n,M[N][N];
int color[N],d[N],f[N],t;
int main(){

  int u,v,k,i,j;

  scanf("%d",&n);
  for(i=0;i<n;i++){
    for(j=0;j<n;j++)
      M[i][j]=0;


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

}
void depth_search(int u){
  int v;
  color[u]=GRAY;
  d[u]=++t;
for(v=0;v<n;v++){
  if(M[u][v]==0)
    continue;
  if(color[v]==WHITE){
    depth_search(v);}
 }
 color[u]=BLACK;
 f[u]=++t;
}
void depth(){
  int u;

  for(u=0;u<n;u++)color[u]=WHITE;
  t=0;
  for(u=0;u<n;u++){
    if(color[u]==WHITE)
      depth_search(u);
  }
  for(u=0;u<n;u++){

    printf("%d %d %d\n",u+1,d[u],f[u]);
  }
  }

C++: #include<stdio.h>
 
#define MAX 101
#define BLACK 0
#define WHITE 2
#define GRAY 1


int f[MAX];
int c=0;
int col[MAX];
int depth[MAX];



int dfs[MAX][MAX];
int k[MAX];



void dfsvisit(int u)
{
  int i;
  col[u] = GRAY;
 


depth[u] =  c++;
  for(i = 0;i < k[u]; i++)
    {
      if(col[dfs[u][i]] == WHITE)
    {
     

      dfsvisit(dfs[u][i]);
   

    }
    }
  col[u] = BLACK;
  f[u] = c++;
}

 







int main(){
int n,i=0;
  
 
 
  for(i=0;i<101;i++)
    {
      col[i] = WHITE;
} 




int j;
int tmp;
 
  scanf("%d",&n);
 
  for(i=1;i<=n;i++)
    {
      scanf("%d",&tmp);

      scanf("%d",&k[i]);

      for(j = 0;j < k[i]; j++)
    {
      scanf("%d",&dfs[i][j]);
    }
    }
  
  for(i = 1;i <= n; i++){
      if(col[i] == WHITE){
     

dfsvisit(i);
    }
    }
  for(j = 1;j <= n; j++)
    {
      /*出力が合わないので補正*/
      printf("%d %d %d\n",j,depth[j]+1,f[j]+1);
    }
 
  return 0;
}

C++: #include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int a[101][101],start[101],end[101],n,p=0,v[101];
void dfs(int u){
	if(!v[u]){v[u]++;
	start[u]=++p;
	r(i,1,n+1)if(a[u][i])dfs(i);
	end[u]=++p;}
}
int main(){
	int q,qq,qqq;
	cin>>n;
	r(i,0,n){cin>>q>>qq;
		r(i,0,qq){cin>>qqq;
			a[q][qqq]++;
		}
	}
	r(i,1,n+1)if(!v[i])dfs(1);
	r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}