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++: #define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;

//#define int long long
#define DBG 0
#define dump(o) if(DBG){cerr<<#o<<" "<<o<<endl;}
#define dumpc(o) if(DBG){cerr<<#o; for(auto &e:(o))cerr<<" "<<e;cerr<<endl;}
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define each(it,c) for(auto it=(c).begin();it!=(c).end();it++)
#define all(c) c.begin(),c.end()
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9 + 7);
const int DONE = 1;
const int YET = 0;
int fin(vector<int>a) {
	rep(i, 0, a.size()) {
		if (a[i] == YET)return i;
	}
	return -1;
}
signed main() {
	int n; cin >> n; vector<vector<int> >vec(n, vector<int>());
	rep(i, 0, n) {
		int u, k; cin >> u >> k;
		u--;
		rep(j, 0, k) {
			int v; cin >> v; v--;
			vec[u].push_back(v);
		}
	}
	vector<int>check(n, 0);
	vector<pair<int, int> >stamp(n);
	stack<int>S;
	S.push(0);
	int t = 1;
	start:
	while (!S.empty()) {
		int u = S.top();
		if (check[u] == YET) {
			stamp[u].first = t++;
			check[u] = DONE;
		}
	here:
		if (DBG) {
			cout << "t == " << t << endl;
			rep(x, 0, n) {
				cout << x + 1 << " " << stamp[x].first << " " << stamp[x].second << endl;
			}
		}
		rep(i, 0, vec[u].size()) {
			if (check[vec[u][i]] == YET) {
				S.push(vec[u][i]);
				check[vec[u][i]] = DONE;
				stamp[vec[u][i]].first = t++;
				u = vec[u][i];
				goto here;
			}
		}
		u = S.top(); S.pop();
		stamp[u].second = t++;
	}
	if (fin(check) != -1) {
		S.push(fin(check));
		goto start;
	}
	rep(i, 0, n) {
		cout << i + 1 << " " << stamp[i].first << " " << stamp[i].second << endl;;
	}

	return 0;
}

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 searchAll(vertex *array, int (*A)[101], int n){
    int time = 0;
    for(int id=1;id<=n;id++)if(!array[id].found)time=search(array,A,id,n,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 = searchAll(array, A, n);
    for(i=1;i<=n;i++)printf("%d %d %d\n",i,array[i].d,array[i].f);
    return 0;
}

C++: #include <iostream>
using namespace std;
int n,g[150][150],c[100],f[100],e[100],cnt=1;
void dfs(int now){
  c[now]=1;
  f[now]=cnt;
  cnt++;
	for(int i=0;i<n;i++){
		if(g[now][i] && c[i]!=1){
      		dfs(i);
      		cnt++;
		}
    }
  e[now]=cnt;
}
int main(){
 
  int a,k,num;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>a>>k;
    for(int j=0;j<k;j++){
      cin>>num;
      g[a-1][num-1]=1;
    }
  }
	for(int i=0;i<n;i++){
	   if(c[i]!=1){
     	 dfs(i);
      	 cnt++;
       }
	}
 
	for(int i=0;i<n;i++){
		cout<<i+1<<" "<<f[i]<<" "<<e[i]<<endl;
	}
  return 0;
 
}

C++: #include <iostream>
#include <set>
#include <vector>
#include <queue>
#include <stack>
#include <utility>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

int g[101][101],n,d[101],f[101];

int main() {
    cin >> n;
    for(int i = 0;i < n;i++) {
        int u,k,v;
        cin >> u >> k;
        for(int j = 0;j < k;j++) {
            cin >> v;
            g[u][v]++;
            g[v][u]++;
        }
    }
    stack<int> dfs;
    int time = 1;
    dfs.push(1);
    d[1] = time;
    while(!dfs.empty()){
        int u = dfs.top();
        bool flag = false;
        for(int i = 1;i <= n;i++){
            if(g[u][i] && d[i] == 0) {
                dfs.push(i);
                time++;
                d[i] = time;
                flag = true;
            }
        }
        if(!flag){
            dfs.pop();
            time++;
            f[u] = time;
        }
    }
    for(int i = 1;i <=n;i++) {
        cout << i << " " << d[i] << " " << f[i] <<endl;
    }
}

C++: #include<iostream>
#include<cstdio>
#define N 100
#define  GRAY 1
#define BLACK 2
using namespace std;
int n,M[N][N];
int color[N],d[N],f[N],tt;
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] == 0)
    {
      dfs_visit(v);
    }
}
  color[u] = BLACK;
  f[u] == ++tt;
}
void dfs()
{
  int u;
  for(u = 0;u<n;u++)
     color[u] = 0;
  tt = 0;
  for(u = 0;u<n;u++)
  {
    if(color[u] == 0) dfs_visit(u);
  }
  for(u = 0;u<n;u++)
  {
    printf("%d %d %d\n",u+1,d[u],f[u]);
  }
}
int main ()
{
  int u,v,k,i,j;
  scanf("%d",&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++)
   {
     scanf("%d %d",&n,&k);
     u--;
     for(int j = 0;j<n;j++)
       {
         scanf("%d",&v);
         v--;
         M[u][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];

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;
    }
}

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;
}