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++: //Depth First Search
#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 n, M[N][N];
int colors[N] = {}, d[N] = {}, f[N] = {}, tt = 1;

void dfs_visit(int u) {
    if(colors[u] == GRAY || colors[u] == BLACK) return;
    d[u] = tt++;
    colors[u] = GRAY;
    for(int i = 0; i < n; i++) {
        if(M[u][i] == 1) dfs_visit(i);
    }
    f[u] = tt++;
    colors[u] = BLACK;
}

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

    dfs();
}

C++: #include <utility>
#include <string>
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

int n;
int a[100][100] = {0};
int k[100] = {0};
int t = 1;
int d[100] = {0};
int f[100] = {0};

int kansu( int i ){
	if ( d[i] != 0 ) return 0;
	d[i] = t;
	t++;
	for ( int j = 0; j < k[i]; j++ ) {
		if ( kansu( a[i][j] ) == 1 ) t++;
	}
	f[i] = t;
	return 1;
}

int main(){
	cin >> n;
	int s;
	for ( int i = 0; i < n; i++ ) {
		cin >> s;
		cin >> k[i];
		for ( int j = 0; j < k[i]; j++ ) {
			cin >> s;
			a[i][j] = s-1;
		}
	}
	for ( int i = 0; i < n; i++ ) {
		if ( kansu(i) == 1 ) t++;
	}
	for ( int i = 0; i < n; i++ ) {
		cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i,n) for (int i=0;i<(int)(n);i++)
#define codefor int test;scanf("%d",&test);while(test--)
#define yn(ans) if(ans)printf("Yes\n");else printf("No\n")
#define YN(ans) if(ans)printf("YES\n");else printf("NO\n")
#define vector2d(type,name,h,...) vector<vector<type>>name(h,vector<type>(__VA_ARGS__))
#define umap unordered_map
#define uset unordered_set
using namespace std;
using ll = long long;
const int MOD=1000000007;
//入力系
void scan(int& a){scanf("%d",&a);}
void scan(long long& a){scanf("%lld",&a);}
template<class T> void scan(T& a){cin>>a;}
template<class T> void scan(vector<T>& vec){for(auto&& it:vec)scan(it);}
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){scan(head);in(tail...);}
//出力系
void print(const int& a){printf("%d",a);}
void print(const long long& a){printf("%lld",a);}
void print(const double& a){printf("%.15lf",a);}
template<class T> void print(const T& a){cout<<a;}
template<class T> void print(const vector<T>& vec){if(vec.empty())return;print(vec[0]);for(auto it=vec.begin();++it!= vec.end();){putchar(' ');print(*it);}}
void out(){putchar('\n');}
template<class T> void out(const T& t){print(t);putchar('\n');}
template <class Head, class... Tail> void out(const Head& head,const Tail&... tail){print(head);putchar(' ');out(tail...);}
//デバッグ系
template<class T> void dprint(const T& a){cerr<<a;}
template<class T> void dprint(const vector<T>& vec){if(vec.empty())return;cerr<<vec[0];for(auto it=vec.begin();++it!= vec.end();){cerr<<" "<<*it;}}
void debug(){cerr<<endl;}
template<class T> void debug(const T& t){dprint(t);cerr<<endl;}
template <class Head, class... Tail> void debug(const Head& head, const Tail&... tail){dprint(head);cerr<<" ";debug(tail...);}
ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }

int main(){
    int n,a,b,c,x;
    in(n);
    vector<vector<int>> graph(n);
    vector<pair<int,int>> time(n);
    rep(i,n){
        in(a,b);
        time[i].first=-1;
        rep(j,b){
            in(c);
            graph[a-1].push_back(c-1);
        }
    }
    stack<int> next;
    int time1=0;
    rep(j,n){
    if(time[j].first==-1){
        time1++;
        next.push(j);
        time[j].first=time1;
        while(!next.empty()){
            x=next.top();
            time1++;
            rep(i,graph[x].size()){
                if(time[graph[x][i]].first==-1){
                    time[graph[x][i]].first=time1;
                    next.push(graph[x][i]);
                    goto skip;
                }
            }
            next.pop();
            time[x].second=time1;
            skip: ;
        }
    }
    }
    rep(i,n){
        out(i+1,time[i].first,time[i].second);
    }
}

C++: #include <iostream>
#include <stack>
using namespace std;

const long N = 100;
const long WHITE = 0;
const long GRAY = 1;
const long BLACK = 2;

long n, M[N + 1][N + 1];
long color[N + 1], d[N + 1], f[N + 1], tt;
long nt[N + 1];

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

void dfs_visit(long r){
	for (long i = 1; i <= n; i++) nt[i] = 0;

	stack<long> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = ++tt;

	while (!S.empty()){
		long u = S.top();
		long 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 (long i = 1; i <= n; i++){
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 0;

	for (long u = 1; u <= n; u++){
		if (color[u] == WHITE) dfs_visit(u);
	}
	for (long i = 1; i <= n; i++){
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
}

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

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

	dfs();

	return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
int time = 0;

void dfs(int cur, vector<vector <int> > &list, vector<int> &d, vector<int> &f) {
		d[cur] =time;
		time +=1;
    for(int i = 0; i < list.size();i++){
      vector<int>::iterator it = list[cur].end();
	  vector<int>::iterator hoge = find(list[cur].begin(),list[cur].end(),i);
      if(d[i] == 0 && (hoge != it ) ){
        dfs(i,list,d,f);
      }
    }
    f[cur] = time;
    time +=1;
}

int main() {
  int np;
  int k,t,x;
  cin >> np ;
 
  vector <vector <int> > list(np);
  for(int i = 0;i<np;i++) {
    cin >> k;
    cin >> t;
    for(int j = 0; j < t ;j++) {
      cin >>x;
      list[k-1].push_back(x-1);
    }
  }
  vector <int> d(np,0);
  vector <int> f(np,0);
  dfs(0,list,d,f);
  for(int i = 0;i < np; i++){
    cout << i+1 <<" "<<d[i]+1 <<" "<<f[i]+1<<endl;
  }


  return 0;
}