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<bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < n; i++)
using namespace std;
using ll = long long;

vector<bool> seen;
vector<int> first;
vector<int> last;

void dfs(const vector<vector<int>> &g, int v, int &ptr){
  first[v] = ptr++;
  seen[v] = true;
  
  for(int i : g[v]){
    if(seen[i]) continue;
    dfs(g,i,ptr);
  }
  
  last[v] = ptr++;
}

int main() {
  int n;
  cin >> n;
  seen.assign(n,false);
  first.resize(n);
  last.resize(n);
  
  vector<vector<int>> g(n);
  
  rep(i,n){
    int u, k;
    cin >> u >> k;
    u--;
    vector<int> v(k);
    rep(j,k){
      cin >> v[j];
      v[j]--;
      g[u].push_back(v[j]);
    } 
  }
  int ptr = 1;
  rep(i,n){
    if(first[i] == 0){
      dfs(g,i,ptr);
    }
  }


  rep(i,n){
    cout << i + 1 << ' ' <<first[i] << ' ' << last[i] << endl;
  } 
}

C++: #include <iostream>
using namespace std;
int a[100][100]={},f[100]={},d[100]={},T[200]={};
int main(){
	int n;
	cin>>n;
	for(int i=0;i<n;i++){
		int u,k;
		cin>>u>>k;
		for(int j=0;j<k;j++){
			cin>>a[u][j];
		}
	}
	T[1]=1;
	f[1]=1;
	for(int time=2;time<=2*n;time++){
		for(int j=0;j<100;j++){
			if(a[T[time-1]][j]==0){
				d[T[time-1]]=time;
				T[time]=T[f[T[time-1]]-1];
				break;
			}
			else if(f[a[T[time-1]][j]]==0){
				f[a[T[time-1]][j]]=time;
				T[time]=a[T[time-1]][j];
				break;
			}
		}
	}
	for(int i=1;i<=n;i++){
		cout<<i<<" "<<f[i]<<" "<<d[i]<<endl;
	}
}

C++: #include <cstdio>

typedef struct vertex_{
    int found;
    int d;
    int f;
}vertex;

int search(vertex *array, int (*A)[101], int id, int n, int time){
    if(array[id].found)return time;
    array[id].found=1;
    array[id].d=++time;
    for(int i=1;i<=n;i++){
        if(A[id][i])time=search(array,A,i,n,time);
    }
    array[id].f=++time;
    return time;
}

int main(){
    int i, j, n, u, k, v;
    scanf("%d",&n);
    vertex array[n+1];
    for(i=1;i<=n;i++)array[i].found=0;
    int A[101][101];
    for(i=1;i<=n;i++){
        for(j=1;j<=n;j++){
            A[i][j]=0;
        }
    }
    for(i=1;i<=n;i++){
        scanf("%d %d",&u,&k);
        for(j=0;j<k;j++){
            scanf("%d",&v);
            A[u][v]=1;
        }
    }
    int time = search(array, A, 1, n, 0);
    for(i=1;i<=n;i++)printf("%d %d %d\n",i,array[i].d,array[i].f);
    return 0;
}

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

vector<int>G[102];
int d[102],f[102];
bool vis[102];
int V;
int cur=0;
/*
void dfs(int id){
    cur++;
    d[id]=cur;
    vis[id]=true;
    for(int i=0;i<G[id].size();i++){
        if(!vis[G[id][i]])
            dfs(G[id][i]);
    }
    f[id]=cur;
}
*/
stack<int> s;
void dfs_visit(int id){
    s.push(id);
    cur++;
    d[id]=cur;
    while(!s.empty()){
        int u=s.top();
        int nex=-1;
        for(int i=0;i<G[u].size();i++){
            if(!vis[G[u][i]]) {
                nex=G[u][i];
                break;
            }
        }
        cur++;
        if(nex==-1){
            s.pop();
            f[u]=cur;
            vis[u]=true;
        }
        else{
            d[nex]=cur;
            s.push(nex);
        }
    }
}

void dfs(){
	int i;
    for(i=1;i<=V;i++){
        if(!vis[i]) dfs_visit(i);
    }
    for(i=1;i<=V;i++){
        cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}
int main(){
    cin>>V;
    memset(vis,false,sizeof(vis));
    for(int i=1;i<=V;i++){
        int id,k;
        cin>>id>>k;
        while(k--){
            int out;
            cin>>out;
            G[id].push_back(out);
        }
        sort(G[id].begin(),G[id].end());
    }
    dfs();
    return 0;
}

C++: #include <iostream>
#include <cstring>
#include <cstdlib>
#include <sstream>
#include <stack>
#include <queue>
#include <list>
#include <stdio.h>
#include <algorithm>
#define MAX 100000
using namespace std;
typedef long long ll;
int map[255][255];
int f[255],d[255],tt=0;
bool vis[255];
void dfs(int n,int u)
{
	if(vis[u]) return;
	vis[u]=true;
	tt++;
	d[u]=tt;
	for(int i=1;i<=n;i++)
	{
		if(map[u][i]) dfs(n,i);
	}
	tt++;
	f[u]=tt;
	return; 
}
int main()
{	
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
		{
			map[i][j]=0;
		}
	for(int i=0;i<n;i++)
	{
		int cur,k,u;
		cin>>cur>>k;
		while(k--)
		{
			cin>>u;
			map[cur][u]=1;
		}
	}
	for(int i=1;i<=n;i++)
	{
		vis[i]=false;
	}
	for(int i=1;i<=n;i++)
	{
		if(!vis[i]) dfs(n,i);
	}
	for(int i=1;i<=n;i++)
	{
		cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
	}
	return 0;
}