Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

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;
}

C++: #include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef long int li;
typedef long double lb;
#define rep(i,j,n) for (ll i = j; i < (n); i++)
#define repr(i,j,n) for(ll i = j; i >= (n); i--)
#define all(x) (x).begin(),(x).end()
#define CLR(mat,f) memset(mat, f, sizeof(mat))
#define IN(a, b, x) (a<=x&&x<b)
#define out(ans) cout << ans << endl
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
typedef pair<ll,ll>P;
const ll mod=1e9+7;
const ll INF = 1LL<<60;

vector<vector<ll> >V;
ll c=0;
vector<vector<ll> >ans;
void dfs(ll x){
  if(ans[x].size()!=0)return;
  c++;
  ans[x].push_back(c);

  rep(i,0,V[x].size()){
    dfs(V[x][i]);
  }
  c++;
  ans[x].push_back(c);
}

int main(){

  ll n;cin>>n;
  V.resize(n);
  ans.resize(n);
  rep(i,0,n){
    ll u;cin>>u;
    --u;
    ll k;cin>>k;
    rep(j,0,k){
      ll a;cin>>a;
      --a;
      V[u].push_back(a);

    }
  }
  rep(i,0,n){
    dfs(i);
  }

  rep(i,0,n)out(i+1<<" "<<ans[i][0]<<" "<<ans[i][1]);






  return 0;
}