Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	timer := 1
	for {
		startNode := findStartNode(childrenMap, timeRecordMap)
		if startNode > 0 {
			visit(startNode, &timer, childrenMap, timeRecordMap)
		} else {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	if x < 0 {
		return -1
	}

	found := false
	i := 0
	for i < len(childrenMap) {
		children := childrenMap[i]
		for j := 0; j < len(children); j++ {
			if children[j] == x {
				x = j + 1
				found = true
				break
			}
		}
		if found {
			i = 0
		} else {
			i++
		}
	}
	return x
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cassert>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define rep(i,n) FOR(i,0,n)
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define vint vector<int>
#define vdouble vector<double>
#define vstring vector<string>
using namespace std;

#include<map>
#include<set>
#include<queue>

typedef long long ll;
typedef unsigned long long ull;

const int MAX_N = 1000000;
static const int INFTY = (1 << 21);

class Edge{
public:
    int from, to, cost;
    Edge(int from = 0, int to = 0, int cost = 0) :
            from(from), to(to), cost(cost){}

    bool operator < (const Edge &e) const{
        return cost < e.cost;
    }
    bool operator >(const Edge &e) const{
        return cost > e.cost;
    }

};

class Node{
public:
    vector<Edge> edges;
    int dist;
    int done;
    int times;
    int timee;

    Node(){
        dist = INFTY;
        done = 0;
    }
};

class Graph{
public:
    vector<Node> nodes;
    Graph(int n) {
        rep(i, n) { Node n;  nodes.push_back(n); }
    }
    Node& operator[](int i){
        return nodes[i];
    }
};

class Data{

public:
    int dist;
    Edge *edge;
    Data(int dist, Edge *edge) {
        this->dist = dist;
        this->edge = edge;
    }

    bool operator < (const Data &d) const{
        return dist < d.dist;
    }
    bool operator >(const Data &d) const{
        return dist > d.dist;
    }
};

Graph G(0);

int V;
int t;

void dfs(int v){
    if (G[v].done != 0) return;

    // fprintf(stderr, "%d %d\n", v, t);

    G[v].done = 1;
    t++;
    G[v].times = t;
    for(auto &e: G[v].edges){
        dfs(e.to);
    }
    t++;
    G[v].timee = t;
}

void dfs_run(){
    t = 0;
    dfs(0);
}

int main() {

    int V;
    cin >> V;
    G = Graph(V);

    rep(i, V){
        int from; cin >> from; from--;
        int e_count; cin >> e_count;

        vint vec;
        rep(j, e_count){
            int to; cin >> to; to--;
            vec.push_back(to);
        }
        sort(vec.begin(), vec.end());
        rep(j, e_count){
            G[from].edges.push_back(Edge(from, vec[j], 1));
        }
    }

    dfs_run();

    rep(i, V){
        fprintf(stdout, "%d %d %d\n", i+1, G[i].times, G[i].timee);
    }
}

C++: #include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <climits>
#include <cstring>


using namespace std;

const int N_MAX = 1000000;

int main(){
  int n;
  cin >> n;
  stack<pair<int, int> > edges;
  stack<pair<int, int> > paths;
  
  int** adjl = new int*[n];
  int* d = new int[n];
  int* f = new int[n];
  
  for(int i=0; i<n; i++){
    adjl[i] = new int[n];
    memset(adjl[i], -1, n * sizeof(adjl[i][0]));
  }
  
  memset(d, -1, n*sizeof(d[0]));
  memset(f, -1, n*sizeof(f[0]));

  for(int i=0; i<n; i++){
    int row_num, k;
    cin >> row_num >> k; row_num--;
    
    for(int j=0; j<k; j++){
      int node_num;
      cin >> node_num; node_num--;
      adjl[row_num][j] = node_num; // [[3, 5, -1 , ...], [1, 3, -1, ...], [1, 2], ...]
    }
  }

  for(int row_num=n-1; row_num>=0; row_num--){
      pair<int, int> p;
      p.first = -1; p.second = row_num; // visited from nowhere
      edges.push(p);
    }

  int time = 1;
  while(!edges.empty()){
    //    cout << "time: " << time << endl;
    
    pair<int, int> edge;
    edge = edges.top(); edges.pop();
    int st, en; st = edge.first; en = edge.second;
    //    cout << "visiting: " << en << " from: " << st << endl;
    
    pair<int, int> path; 
    // record path to go back
    if(st > -1){ // exclude (-1, node)
      path.first = en; path.second = st;
      // avoid inf loop: if the node is not finished, have to go back at some point
      if(f[path.second] == -1){
	paths.push(path);
	// cout << "<" << path.first << ", " << path.second << "> pushed as a path." << endl;
      }
    }    
    
    // if first time visit, mark as visited
    if(d[en] == -1) d[en] = time;
    
    // if not first time, check if it was finished.
    // if it was already finished, continue
    if(f[en] != -1){
      continue;
    }
    
    // counter for opened nodes
    int unvisited_node_num = 0;

    // open node (reverse order)
    for(int i=n-1; i>=0; i--){
      int next_node = adjl[en][i];
      // cout << "next_node: " << next_node << endl;
      // undefined dest or visited, continue
      if(next_node == -1) continue;
      if(d[next_node] != -1){
	// if num_to_visit[en] > 0;
	continue;
      }
      // if unvisited, push into stack
      unvisited_node_num++;
      pair<int, int> next_edge; next_edge.first = en; next_edge.second = next_node;
      edges.push(next_edge);
      // cout << "<" << next_edge.first << ", " << next_edge.second << "> pushed." << endl;
    }

    // if there are no unvisited linked nodes anymore, mark the node finished
    if(unvisited_node_num == 0){
      // cout << "going back..." << endl;
      f[en] = time + 1;
      // cout << "f[" << en << "]: " << f[en] << endl;
      
      // way to go back
      if(paths.empty()) break;
      path = paths.top(); paths.pop();
      edges.push(path);
      // cout << "path pushed." << endl;
    }
    time++;
  }

  // print 'i+1, d[i], f[i]'
  
  for(int i=0; i<n; i++){
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
  
  for(int i=0; i<n; i++){
    delete[] adjl[i];
  }
  delete[] adjl;
  delete[] d;
  delete[] f;
  
  return 0;
}