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>
#include<cstdio>
using namespace std;
int arisutoteresu[200][200] = {0};
int imap[200][200] = {0};
int n,u,k[200];
int GetIt[200]={0};
int FinIt[200]={0};
bool used[200] = {false};
int fincou=1;
void dfs(int where,int find){
  fincou++;
 
  GetIt[where]=find;
  if(k[where] != 0){
    for(int i=0;i<k[where];i++){
      if(!used[where]){
	dfs(imap[where][i],find+1);
	fincou++;
	used[where] = true;
      }
    }
  }
    FinIt[where] = fincou;
    
}

int main(){
 
  int ad;
  
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    cin >> u;
    cin >> k[u];
    for(int j=0;j<k[u];j++){
      cin >> ad;
      arisutoteresu[u][ad] = 1;
      imap[u][j] = ad; 
    }
  }


  for(int j=0;j<n;j++)used[j] = false;
  dfs(1,1);

  for(int i=0;i<n;i++){
    cout << i << " " << GetIt[i+1]  << " " << FinIt[i+1];
    cout << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <vector>
#include <stack>
using namespace std;
#define maxn 105
const int WHITE = 0;
const int GRAY  = 1;
const int BLACK = 2;
int g[maxn][maxn];
int d[maxn],f[maxn];
stack<int> s;
int color[maxn];
int t,n;
void dfs_visit(int u)
{
    color[u]=GRAY;
    d[u]=++t;
    for(int v=1;v<=n;v++)
    {
        if(g[u][v]==0) continue;
        if(color[v]==WHITE)
            dfs_visit(v);
    }
    color[u]=BLACK;
    f[u]=++t;
}
void dfs()
{
    for(int u=1;u<=n;u++)
        color[u]=WHITE;
    for(int u=1;u<=n;u++)
    {
        if(color[u]==WHITE)
            dfs_visit(u);
    }
    for(int u=1;u<=n;u++)
        printf("%d %d %d\n",u,d[u],f[u]);
}
int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        int u,k;
        scanf("%d%d",&u,&k);
        for(int j=1;j<=k;j++)
        {
            int v;
            scanf("%d",&v);
            g[u][v]=1;
        }
    }
    dfs();
    return 0;
}

C++: #include <iostream>
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] = {0}, color[N] = {0}, d[N], f[N], tt = 0, n;

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

void dfs() {
  int u;
  for (u = 0; u < n; u++) {
    if (color[u] == WHITE) {
      dfs_visit(u);
    }
  }

  for (u = 0; u < n; u++) {
    cout << u + 1 << " " << d[u] << " " << f[u] << endl;
  }
}

int main(void) {
  int u, v, k, i, j;

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

  return 0;
}

C++: #include <vector>
#include <iostream>
#include <set>
#include <cstdio>
#include <queue>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <ctime>
#include <cmath>
#include <complex>
#include <algorithm>
#include <tuple>
#include <algorithm>
#include <limits>
#include <map>

using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;

int d[110], f[110];
vector<int> g[110];
int t;
bool used[110];
void solve(int i) {
    if (used[i]) return;
    used[i] = true;
    t++;
    d[i] = t;
    for (int j: g[i]) {
        solve(j);
    }
    t++;
    f[i] = t;
}

int main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int id, u;
        cin >> id >> u;
        for (int j = 0; j < u; j++) {
            int a;
            cin >> a;
            g[i].push_back(a-1);
        }
    }
    t = 0;
    fill_n(used, 110, false);
    for (int i = 0; i < n; i++) {
        solve(0);
    }
    for (int i = 0; i < n; i++) {
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
    return 0;
}

C++: #include <iostream>
using namespace std;
const int MAXn=100;

int n,M[MAXn][MAXn]={0},col[MAXn];//color:0=white,1=gray,2=brack
int d[MAXn],f[MAXn],t;

void dfs_visit(int u)
{
	int v;
	col[u]=1;
	d[u]=++t;
	for(v=0;v<n;v++)
	{
		if(M[u][v]==0)continue;
		if(col[v]==0)dfs_visit(v);
	}
	col[u]=2;
	f[u]=++t;
	return;
}

void dfs()
{
	int u;
	for(u=0;u<n;u++)col[u]=0;
	t=0;
	
	for(u=0;u<n;u++)if(col[u]==0)dfs_visit(u);
	
	for(u=0;u<n;u++)cout<<u+1<<" "<<d[u]<<" "<<f[u]<<endl;
	
	return;
}

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

// u に隣接する v を番号順に取得
int next(int u) {
  for ( int v = nt[u]; v < n; v++ ) {
    nt[u] = v + 1;
    if ( M[u][v] ) return v;
  }
  return -1;
}

// スタックを用いた深さ優先探索
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() {
  // 初期化
  for ( int i = 0; i < n; i++ ) {
    color[i] = WHITE;
    nt[i] = 0;
  }
  tt = 0;

  // 未訪問の u を始点として深さ優先探索
  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;
}

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 < n; j++ ) {
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }

  dfs();

  return 0;
}

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

int n,t;
vector<vector<int>> M(101,vector<int>(101,0));
vector<int> color(101,0);
vector<int> d(101,0),f(101,0);

void dfs(int u){
    color[u]=1;
    d[u]=++t;
    for(int v=1;v<n+1;v++){
        if(M[u][v]&&color[v]==0){
            dfs(v);
        } 
    }
    color[u]=2;
    f[u]=++t;
}

int main(){
    cin>>n;
    for(int i=1;i<n+1;i++){
        int a,b,k;
        cin>>a>>k;
        for(int j=0;j<k;j++){
            cin>>b;
            M[a][b]=1;
        }
    }

    t=0;
    for(int i=1;i<n+1;i++){
        if(color[i]==0){
            dfs(i);
        }
    }

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