Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve(parseProblem())
}

type graph struct {
	size  int
	edges [][]int
}

func parseProblem() *graph {
	n := scanInt(sc)
	g := &graph{
		size:  n,
		edges: make([][]int, n),
	}
	for i := 0; i < g.size; i++ {
		_ = scanInt(sc)
		k := scanInt(sc)
		g.edges[i] = make([]int, k)
		for j := 0; j < k; j++ {
			g.edges[i][j] = scanInt(sc) - 1
		}
	}
	return g
}

func resolve(g *graph) {
	ds := make([]int, g.size)
	fs := make([]int, g.size)
	time := 0
	for i := 0; i < len(ds); i++ {
		if ds[i] == 0 {
			time++
			time = _dfs(ds, fs, time, g, i)
		}
	}
	for i := 0; i < len(ds); i++ {
		fmt.Println(i+1, ds[i], fs[i])
	}
	return
}

func _dfs(ds, fs []int, time int, g *graph, idx int) int {
	ds[idx] = time
	for _, next := range g.edges[idx] {
		if ds[next] > 0 {
			continue
		}
		time++
		time = _dfs(ds, fs, time, g, next)
	}
	time++
	fs[idx] = time
	return time
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

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

#define MAX 101

using namespace std;

int visited[MAX],d[MAX],f[MAX],called[MAX];
int tt=0;
vector<int> G[MAX];
stack<int> S;

int getNext(int u){
  if(called[u]>=G[u].size()) return -1;
  else{
    int x=G[u][called[u]];
    called[u]++;
    return x;
  }
}


void dfs(int u){
  S.push(u);
  visited[u]=1;
  d[u]=++tt;
  while(S.empty()==false){
    int x=S.top();
    int v=getNext(x);
    if(v!=-1){
      if(visited[v]==0){
        visited[v]=1;
        d[v]=++tt;
        S.push(v);
      }
    }else{
      S.pop();
      visited[x]=1;
      f[x]=++tt;
    }
  }
}

int main(){
  int n; cin >> n;
  for(int i=1;i<=n;i++){
    visited[i]=0;
    called[i]=0;
  }
  for(int i=0;i<n;i++){
    int u,k; cin >> u >> k;
    for(int i=0;i<k;i++){
      int v; cin >> v;
      G[u].push_back(v);
    }
  }
  for(int i=1;i<=n;i++){
    if(visited[i]==0){
      dfs(i);
    }
  }
  for(int i=1;i<=n;i++){
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
}

C++: #include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string>
#include <stdlib.h>
#include <queue>
#include <stack>
#include <utility>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define INF 1000000001
#define mod 1000000007
using namespace std;

int main(){
	int n;
	cin>>n;
	vector<vector<int> > v(n);
	vector<int> k(n);
	int x;
	rep(i,n){
		cin>>x;
		cin>>k[i];
		v[i].resize(k[i]);
		rep(j,k[i]){
			cin>>v[i][j];
			v[i][j]--;
		}
	}
	vector<int> a(n),b(n);
	stack<int> s;
	int count=1;
	s.push(0);
	a[0]=1;
	while(s.empty()==0){
		count++;
		int x=s.top();
		rep(i,k[x]){
			if(a[v[x][i]]==0){
				s.push(v[x][i]);
				a[v[x][i]]=count;
				break;
			}
			if(i==k[x]-1){
				k[x]=0;
			}
		}
		if(k[x]==0){
				b[x]=count;
				s.pop();
		}
	}

	rep(i,n){
		cout<<i+1<<" "<<a[i]<<" "<<b[i]<<endl;;
	}

		



	return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string>
#include <stdlib.h>
#include <queue>
#include <stack>
#include <utility>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define INF 1000000001
#define mod 1000000007
using namespace std;

int main(){
	int n;
	cin>>n;
	vector<vector<int>> v(n);
	vector<int> k(n);
	int x;
	rep(i,n){
		cin>>x;
		cin>>k[i];
		v[i].resize(k[i]);
		rep(j,k[i]){
			cin>>v[i][j];
			v[i][j]--;
		}
	}
	vector<int> a(n),b(n);
	stack<int> s;
	int count=1;
	s.push(0);
	a[0]=1;
	while(s.empty()==0){
		count++;
		int x=s.top();
		rep(i,k[x]){
			if(a[v[x][i]]==0){
				s.push(v[x][i]);
				a[v[x][i]]=count;
				break;
			}
			if(i==k[x]-1){
				k[x]=0;
			}
		}
		if(k[x]==0){
				b[x]=count;
				s.pop();
		}
	}

	rep(i,n){
		cout<<i+1<<" "<<a[i]<<" "<<b[i]<<endl;;
	}

		



	return 0;
}

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

struct Vertex {
	int id;
	vector<int> vertices;
	int visited;
	int completed;
};

int getNext(Vertex vertices[], int id){
	Vertex v = vertices[id-1];
	int size = v.vertices.size();
	for(int i=0;i<size;i++){
		int nId = v.vertices[i];
		if (vertices[nId-1].visited==-1){
			return nId;
		}
	}
	return -1;
}

void dfs(int n, Vertex vertices[]){
	
	int time = 0;

	for(int i=0;i<n;i++){
		Vertex cur=vertices[i];
		stack<int> st;
		if(cur.visited==-1){
			st.push(cur.id);
		}
		while(!st.empty()){
			int id=st.top();
			if(vertices[id-1].visited==-1){
				vertices[id-1].visited=++time;
			}
			int nId=getNext(vertices,id);
			if(nId!=-1){
				vertices[nId-1].visited=++time;
				st.push(nId);
			} else {
				vertices[id-1].completed=++time;
				st.pop();
			}
		}
	}
}

int main(){
	int n;
	cin >> n;
	Vertex vertices[n];
	for(int i=0;i<n;i++){
		int id;
		cin >> id;
		vertices[i].id = id;
		vertices[i].visited = -1;
		vertices[i].completed = -1;
		int cnt;
		cin >> cnt;
		for(int j=0;j<cnt;j++){
			cin >> id;
			vertices[i].vertices.push_back(id);
		}
	}
	
	dfs(n,vertices);
	
	for(int i=0;i<n;i++){
		Vertex v = vertices[i];
		cout << v.id << " ";
		cout << v.visited << " ";
		cout << v.completed << endl;
	}
	return 0;
}

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

int a[100][100];
int n,p,q,r;
int T[100],F[100];
int Time = 0;
void dfs(int cur) {
	T[cur] = Time;
	Time += 1;
	cerr << "visiting " << cur << ' ' << Time << endl;
	for (int dst=0; dst < n; ++dst) {
		if(a[cur][dst] == 1 && T[dst] == -1) {
			dfs(dst);
		}
	}
	F[cur] = Time;
	Time += 1;
}

int main() {
	cin >> n;
	for (int i=0; i<n; ++i) {
		cin >> p >> q;
		T[i] = -1;
		for (int j=0; j<q; ++j) {
			cin >> r;
			a[p-1][r-1] = 1;
		}
	}
	dfs(0);
	for (int i=0; i<n; ++i) {
		cout << i+1 << " " << T[i]+1 << " " << F[i]+1 << endl;
	}
}