Go: package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)
	g := make([][]int, n+1)
	for i := 0; i < n; i++ {
		var u,k int
		fmt.Scan(&u)
		fmt.Scan(&k)
		g[u] = make([]int, k)
		for j := 0; j < k; j++ {
			fmt.Scan(&g[u][j])
		}
	}

	d := make([]int, n+1)
	f := make([]int, n+1)
	t := 1
	for i := 1; i <= n; i++ {
		t = dfs(&g, &d, &f, i, t)
	}

	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, d[i], f[i])
	}
}

func dfs(g *[][]int, d *[]int, f *[]int, id int, t int) int {
	if (*d)[id] > 0 {
		return t
	}
	(*d)[id] = t
	t += 1
	for i := 0; i < len((*g)[id]); i++ {
		t = dfs(g, d, f, (*g)[id][i], t)
	}
	(*f)[id] = t
	return t+1
}

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

int r[101][101];
int d[101], f[101], num, visit[100]={0}, p=1;

void dfs(int n){
    if(visit[n]!=1){
        visit[n] = 1;
        d[n] = p++;
        for(int i=1; i<=num; i++)
            if(r[n][i]) dfs(i);
        f[n] = p++;
    }
}

int main(void){
    int u, k, v;
    cin >> num;
    for(int i=1; i<=num; i++){
        cin >> u >> k;
        for(int j=1; j<=k; j++)
            cin >> v;
            r[u][v]=1;
    }
    for(int i=1; i<=num; i++){
        if(visit[i]!=1) dfs(i);
    }
    for(int i=1; i<=num; i++)
        cout << i << " " << d[i] << " " << f[i] << endl;
    return 0;
}

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

struct StSeq
{
  int m_nBgn;
  int m_nEnd;

  StSeq() : m_nBgn(0), m_nEnd(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<StSeq>& rvoDFSrch)
{
  int nMaxSiz;
  cin >> nMaxSiz;

  rvvnAdjcy.resize(nMaxSiz + 1, vector<int>(nMaxSiz + 1, 0));
  for (int i = 0; i < nMaxSiz; ++i)
  {
    int nx, nSecSiz;
    cin >> nx >> nSecSiz;
    for (int j = 0; j < nSecSiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  StSeq oSeq;
  rvoDFSrch.resize(nMaxSiz + 1, oSeq);
}

void fnDepthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, vector<StSeq>& rvoDFSrch, int nx)
{
  static int stnCnt = 0;

  if (rvoDFSrch[nx].m_nBgn)  return;
  rvoDFSrch[nx].m_nBgn = ++stnCnt;

  for (int ny = 1; ny < cnrvvnAdjcy.size(); ++ny)
    if (cnrvvnAdjcy[nx][ny] == 1  &&
        nx != ny               )
      fnDepthFirstSearch(cnrvvnAdjcy, rvoDFSrch, ny);

  rvoDFSrch[nx].m_nEnd = ++stnCnt;
}

void fnResult(const vector<StSeq>& cnrvoDFSrch)
{
  for (int i = 1; i < cnrvoDFSrch.size(); ++i)
    cout << i <<  " " << cnrvoDFSrch[i].m_nBgn << " " << cnrvoDFSrch[i].m_nEnd << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  vector<StSeq> voDFSrch;

  fnInput(vvnAdjcy, voDFSrch);
  for (int nx = 1; nx < voDFSrch.size(); ++nx)
    fnDepthFirstSearch(vvnAdjcy, voDFSrch, nx);
  fnResult(voDFSrch);

  return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <numeric>
#include <queue>
#include <stack>
#include <map> 
#include <set>
#include <string>
#include <functional>
#include <list>
#include <random>
#include <time.h>
#include <iomanip>
#include <assert.h>
#include <numeric>
#include <new>
#include <sstream>
#include <complex>
#define BIT(nr) (1ULL << (nr))
#define int long long
#define ll long long
#define double long double
#define mod 1000000007
#define MAXN (int)1e+5 * 2+1
#define LL_MAX 9223372036854775807	
#define LL_HALFMAX 9223372036854775807 / 2	
#define MIN -(9223372036854775807 / 2)
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
#define REPS(i,x) for(int i=1;i<=(int)(x);i++)
#define RREP(i,x) for(int i=((int)(x)-1);i>=0;i--)
#define RREPS(i,x) for(int i=((int)(x));i>0;i--)
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define mp make_pair
template<typename T1, typename T2> inline void chmin(T1 & a, T2 b) { if (a > b) a = b; }
template<typename T1, typename T2> inline void chmax(T1& a, T2 b) { if (a < b) a = b; }

using namespace std;

using Weight = int;
using Flow = int;
struct Edge {
	int src, dst;

	// libalgo のものに追加、メンバを追加するだけなので互換性は崩さないはず、逆辺のG[e.dstの]インデックスを保持
	int rev;
	Weight weight;
	Flow cap;
	Edge() : src(0), dst(0), weight(0) {}
	Edge(int s, int d, Weight w) : src(s), dst(d), weight(w) {}
	bool operator<(const Edge& right) const {
		return dst < right.dst;
	}
};

using Edges = std::vector<Edge>;
using Graph = std::vector<Edges>;
using Array = std::vector<Weight>;
using Matrix = std::vector<Array>;

void add_edge(Graph& g, int a, int b, Weight w = 1) {
	g[a].emplace_back(a, b, w);
	g[b].emplace_back(b, a, w);
}
void add_arc(Graph& g, int a, int b, Weight w = 1) { g[a].emplace_back(a, b, w); }

signed main() {
	int n;
	cin >> n;
	Graph G(n + 1);
	rep(i, n) {
		int u, k;
		cin >> u >> k;
		rep(j, k) {
			int v;
			cin >> v;
			add_arc(G, u, v);
		}
	}

	REPS(i, n) {
		sort(ALLOF(G[i]));
	}

	vector<int> d(n + 1, 0), f(n + 1, 0);

	function<int(int, int)> dfs = [&](int n, int t) -> int {
		if (d[n]) {
			return t - 1;
		}

		d[n] = t;
		for (Edge e : G[n]) {
			chmax(t, dfs(e.dst, t + 1));
		}
		return f[n] = ++t;
	};

	int nowTime = 1;
	REPS(i, n) {
		nowTime = dfs(i, nowTime) + 1;
	}

	REPS(i, n) {
		cout << i << " " << d[i] << " " << f[i] << "\n";
	}

	return 0;
}

C++: #include<iostream>
using namespace std;
int visit[101],d[101],f[101],t;
//
int n,M[101][101];
static const int WHITE=0; //未訪問
static const int GRAY=1; //訪問済み
void dfs(int u){
  visit[u]=GRAY; //訪問した
  d[u]=++t; //発見した時刻
  for(int v=0;v<n;++v){
    if(M[u][v]==0) continue;
    if(visit[v]==WHITE) dfs(v);
  }
  f[u]=++t;
}
int main(){
  int u,v,k,m;
  cin>>n;
   for(int i=0;i<n;++i){
    cin>>u>>k;
    u--; //頂点番号をあわせてる
    for(int j=0;j<k;++j){
      cin>>v;
      v--;
      M[u][v]=1;
    }
   }
  for(int i=0;i<n;++i){
    if(visit[i]==WHITE) dfs(i);
  }
  for(int i=0;i<n;++i){
    cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <string>
#include <cstdio>
#include <queue>
#include <list>
using namespace std;

int n;

struct Node{
public:
  int id, d, f;
  vector<int> c;
  Node(){d = 1000000007;f = 0;}
};

vector<Node> v(101);

void rec(int id, int &t){
  if(v[id].f)return;
  v[id].d = min(v[id].d, ++t);
  for(int i=0;i<v[id].c.size();i++) {
    rec(v[id].c[i], t);
  }
  v[id].f = max(v[id].f, ++t);
}


bool asc(const Node &right, const Node &left){return right.id < left.id;}

int main(){
  cin >> n;
  
  v[0].id = 0;  
  for(int i=1;i<=n;i++){
    int t, a;  cin >> a >> t;
    vector<int> b(t);
    for(int j=0;j<t;j++){
      int val;cin >> val;
      b[j] = val;
    }
    v[a].id = a;
    v[a].c = b;
  }
  sort(v.begin(), v.end(), asc);

  int ti = 0;
  rec(1, ti);

  for(int i=1;i<=n;i++){
    printf("%d %d %d\n", v[i].id, v[i].d, v[i].f);
  }
  return 0;
}