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
		}
	}

	// TODO: always start with 1?
	timer := 1
	visit(1, &timer, childrenMap, timeRecordMap)
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

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 <bits/stdc++.h>
using namespace std;
using ll = long long;
#define FOR(i,a,b) for(ll i = (a); i < (ll)(b); ++i)
#define REP(i,n) FOR(i,0,n)
const double PI = acos(-1), EPS = 1e-10;
const ll MOD = 1e9+7;
int t=0;
vector<int> d,f;
vector<bool> used;
void dfs(int now,vector<vector<int>> &gr){
  if(used[now]) return;
  used[now] = true;
  t++;
  d[now] = t;
  REP(i,gr[now].size()){
    dfs(gr[now][i],gr);
  }
  t++;
  f[now] = t;
}
signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  d.resize(n);
  f.resize(n);
  used.assign(n,false);
  vector<vector<int>> gr(n);
  REP(i,n){
    int k;
    cin >> k >> k;
    REP(j,k){
      int v;
      cin >> v;
      gr[i].push_back(v-1);
    }
  }
  REP(i,n){
    dfs(i,gr);
  }
  REP(i,n){
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
}

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

int n, G[101][101], S[101], T[101];

int dfs(int p, int s) {
    if (S[p] != 0) return 0;
    S[p] = s;
    s++;
    for (int i = 0; i < n; i++) {
        if (G[p][i] == 1) {
            s = max(s, dfs(i, s) + 1);
        }
    }
    T[p] = s;
    return s;
}


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

    dfs(0, 1);

    for (int i = 0; i < n; i++)
        printf("%d %d %d\n", i + 1, S[i], T[i]);

    return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;
typedef vector <int> vi;
typedef vector <vi> vvi;
int counter=0;

int addedge(vvi &graph, int y, int x, int val=1){
	graph[y][x] = val;
	return val;
}

int make_graph(vvi &graph, vvi &stamp){
	int n1=graph.size(), n2, row, col;

	for (int j=0; j<n1; j++){
		cin>>row;
		cin>>n2;
		for (int i=0; i<n2; i++){
			cin>>col;
			addedge(graph, row-1, col-1);
		}
		stamp[j][0] = -1;
	}
	return 0;
}

int Depth_First_Search(vvi &graph, vvi &stamp, int key=0){
	if (stamp[key][0] != -1) return 0;
	stamp[key][0] = ++counter;
	for (int i=0; i<int(graph[0].size()); i++){
		if (graph[key][i]==1 && stamp[i][0]==-1){
			Depth_First_Search(graph, stamp, i);
		}
	}
	stamp[key][1] = ++counter;
	return 0;
}

int resultout(vvi &stamp){
	for (int i=0; i<int(stamp.size()); i++){
		cout<<i+1<<" "<<stamp[i][0]<<" "<<stamp[i][1]<<endl;
	}
	return 0;
}

int main(void){

	int n, row;
	cin>>n;
	vvi G(n, vi(n)), stamp(n, vi(2));

	make_graph(G, stamp);

	for (int i=0; i<n; i++){
		Depth_First_Search(G, stamp, i);
	}
	resultout(stamp);

	return 0;
}

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

int n;
int M[100][100];
int color[100], d[100], f[100];
int time = 1;

void Dfs(int u) {
  color[u] = 1;
  d[u] = time;
  time++;
  for (int v = 0; v < n; v++) if (M[u][v] && color[v] == 0) Dfs(v);
  color[u] = 2;
  f[u] = time;
  time++;
}

int main() {
  cin >> n;

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

  Dfs(0);

  for (int i = 0; i < n; i++) cout << i + 1 << " " << d[i] << " " << f[i] << endl;

  return 0;
}

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

int main(){
 int n,k,v,u;
  cin>>n;

  int V[100][100]; //隣接リスト
  int cnt[100]; //各点においてどこまでみたかの把握
  int d[100];
  int f[100];
  int time=1;
  int l=0;
  int come[100]; //その点はどこからきたかの把握

  //初期化
  for(int i=0;i<100;i++){
    for(int j=0;j<100;j++){
      V[i][j]=0;
      cnt[j]=0;
      d[j]=0;
      f[j]=0;
      come[j]=0;
    }
  }
  //グラフ情報の読み込み
 int  m=0;
  for(int i=0;i<n;i++){
    cin>>u;
    cin>>k;
    for(int j=0;j<k;j++){
      cin>>v;
      V[u-1][m]=v;
      m++;
    }
    m=0;
  }


  //スタートは0
 d[0]=1;
 time++;
  while(1){

    if(time==2*n+1) break;
    //先がありかつそこは探索終了していない
    if(V[l][cnt[l]]!=0 && f[V[l][cnt[l]]-1]==0){ 
     
      if(d[V[l][cnt[l]]-1]==0) d[V[l][cnt[l]]-1]=time;

   come[V[l][cnt[l]]-1]=l;
      cnt[l]++;
      l=V[l][cnt[l]-1]-1; 

      time++;
      //先がないまたはさきが探索終了している
    }else{

      if(d[l]==0) d[l]=time;
       f[l]=time;
      l=come[l];
      time++;

    }

  }
  /*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    cout<<V[i][j]<<" ";
    if(j==n-1) cout<<endl;
  }
  }
  */
  //出力
  for(int i=0;i<n;i++){

    cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }


  return 0;
}

C++: //#include <bits/stdc++.h>
#include<iostream>
#include<stack>
#define MAX 100
#define BLACK 2
#define WHITE 0
#define GRAY 1
using namespace std;

void dfsInit();
void dfs(int);
int next(int);

int n,A[MAX][MAX];
int color[MAX],d[MAX],f[MAX],nt[MAX];
int time1;
int main(){
  int i,j,u,v,k;
  cin >> n;
  for(i = 0; i < n; i++){
    for(j = 0; j< n; j++){
      A[i][j] = 0;
    }
  }
  for(i = 0; i < n; i++){
    cin >> u;
    cin >> k;
    u = u-1;
    for(j = 0; j < n; j++){
      cin >> v;
      v = v-1;
      A[u][v] = 1;
    }
  }
  dfsInit();
  return 0;
}

void dfsInit(){
  for(int i = 0; i < n; i++){
    color[i] = WHITE;
    nt[i] = 0;
  }
  time1 = 0;
  for(int u = 0; u < n; u++){
    if(color[u] == WHITE){
      dfs(u);
    }
  }
  for(int i = 0; i < n; i++){
    //printf("%d %d %d\n",i+1,d[i],f[i]);
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
}

int next(int u){
  int v;
  for(v = nt[u]; v < n; v++){
    nt[u] = v+1;
    if(0 < A[u][v]){
      return v;
    }
  }
  return -1;
}
void dfs(int u){
  for(int i = 0; i < n; i++){
    nt[i] = 0;
  }
  stack<int> S;
  S.push(u);
  color[u] = GRAY;
  d[u] = ++time1;
  while(!S.empty()){
    int r = S.top();
    int v = next(u);
    if(v != -1){
      if(color[v] == WHITE){
        color[v] = GRAY;
        d[v] = ++time1;
        S.push(v);
      }
    }
    else{
      S.top();
      color[r] = BLACK;
      f[r] = ++time1;
    }
  }
}