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;

#define MAX 105
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n, M[MAX][MAX];
int color[MAX], d[MAX], f[MAX], timer;
int nt[MAX];

//uに隣接するvを小さい方から取得
int next(int u){
    for(int v=nt[u]; v<=n; v++){
        nt[u] = v+1;
        if(M[u][v]) return v;
    }
    return -1;
}

void dfs_visit(int r){
    for(int u=1; u<=n; u++) nt[u] = 1;

    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    timer++;
    d[r] = timer;

    while(!(S.empty())){
        int u = S.top();
        int v = next(u);
        if(v != -1){
            //隣接してて行けるところがある
            if(color[v] == WHITE){
                color[v] = GRAY;
                timer++;
                d[v] = timer;
                S.push(v);
            }
        }else{
            //もう隣接してて行けるところがない
            S.pop();
            color[u] == BLACK;
            timer++;
            f[u] = timer;
        }
    }
}

void dfs(){
    //初期化
    for(int u=1; u<=n; u++){
        color[u] = WHITE;
        nt[u] = 1;
    }
    timer = 0;

    //各頂点に対して白なら訪問する。
    for(int u=1; u<=n; u++){
        if(color[u] == WHITE) dfs_visit(u);
    }
    //出力
    for(int u=1; u<=n; u++){
        printf("%d %d %d\n", u, d[u], f[u]);
    }
}

//グラフの深さ優先探索(再帰を用いる)
int main(){
    cin >> n;
    //隣接リスト表現→隣接行列表現への変換
    for(int i=1; i<=n; i++){
        for(int j=1; j<=n; j++){
            M[i][j] = 0;
        }
    }
    for(int i=1; i<=n; i++){
        int u, k;
        cin >> u >> k;
        for(int j=1; j<=k; j++){
            int v;
            cin >> v;
            M[u][v] = 1;
        }
    }

    dfs();

    return 0;
}

C++: #include <iostream>


int D[100];
int F[100];
int V[100][100];

int cnt = 0;
int n;

void dfs(int r) {
    D[r] = ++cnt;
    for (int i = 0; i < n; i++) {
        if ((V[r][i] == 1) && (D[i] == 0)) {
            dfs(i);
        }
    }
    F[r] = ++cnt;
}

int main() {
    std::cin >> n;
    for (int i = 0; i < n; i++) {
        int id, e_num;
        std::cin >> id >> e_num;
        for (int j = 0; j < e_num; j++) {
            int t;
            std::cin >> t;
            V[id - 1][t - 1] = 1;
        }
    }

    dfs(0);

    for (int i = 0; i < n; i++) {
        std::cout << i + 1 << " " << D[i] << " " << F[i] << std::endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

#define WHITE 0
#define GRAY 1
#define BLACK 2

static const int N=100;

int n, M[N][N];
int color[N], d[N], f[N], tt;

void dfs_visit(int u) {
   color[u] = GRAY;
   d[u] = ++tt;
   rep(v, n) {
      if (M[u][v] == 0) continue;

      if(color[v] == WHITE) {
         dfs_visit(v);
      }
   }
   color[u] = BLACK;
   f[u] = ++tt;
}

void dfs() {
   int u;
   for(u = 0; u < n; u ++) {
      color[u] = WHITE;
   }

   for(u = 0; u < n; u ++) {
      if(color[u] == WHITE) dfs_visit(u);
   }

   for(u =0; u<n;u++) {
      printf("%d %d %d\n", u+1, d[u], f[u]);
   }
}

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

   // graphを0で初期化
   for(int i = 0; i < n; i ++) {
      for(int j = 0; j < n; j ++) {
         M[i][j] = 0;
      }
   }

   // 隣接リストを隣接行列に変換
   for(int i = 0; i < n; i ++) {
      scanf("%d %d", &u, &k);
      u--;
      for(int j = 0; j < k; j++) {
         scanf("%d", &v);
         v--;
         M[u][v] = 1;
      }
   }

   dfs();
   return 0;
}

C++: #include <stdio.h>
#define REP(i,n) for(int i=0;i<n;i++)
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
int n,M[N][N]={0};
int color[N]={WHITE},D[N],F[N],tt=0;
void DFS_VISIT(int u){
  int v;
  color[u]=GRAY;
  D[u]=++tt;
  REP(v,n){
    if(M[u][v]==0) continue;
    if(color[v]==WHITE) DFS_VISIT(v);
  }
  color[u]=BLACK;
  F[u]=++tt;
}
void DFS(){
  int u;
  REP(u,n) if(color[u]==WHITE) DFS_VISIT(u);
  REP(u,n) printf("%d %d %d",u+1,D[u],F[u]);
}
int main(){
  int u,v,i,j,k;
  scanf("%d",&n);
  REP(i,n){
    scanf("%d %d",&u,&k);
    REP(j,k){
      scanf("%d",&v);
      M[--u][--v]=1;
    }
  }
  DFS();
  return 0;
}

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

static const int DFS_VISIT_NO   = 0;
static const int DFS_VISIT_NOW  = 1;
static const int DFS_VISIT_DONE = 2;

static int g_time = 0;
static int g_setime[100][2] = {0};

void DfsVisit(int graph[][100], int num, int node, int state[])
{
    int i;

    ++g_time;
    g_setime[node][0] = g_time;

    state[node] = DFS_VISIT_NOW;

    for (i = 0; i < num; i++) {
        if ((graph[node][i] == 1) && (state[i] != DFS_VISIT_DONE)) {
            DfsVisit(graph, num, i, state);
        }
    }

    state[node] = DFS_VISIT_DONE;

    ++g_time;
    g_setime[node][1] = g_time;

    return;
}


void DFS(int graph[][100], int num)
{
    int i;
    int state[100] = {0};


    for (i = 0; i < num; i++) {
        if (state[i] == DFS_VISIT_NO) {
            DfsVisit(graph, num, i, state);
        }
    }

    for (i = 0; i < num; i++) {
        printf("%d %d %d\n", i+1, g_setime[i][0], g_setime[i][1]);
    }

    return;
}

int main(void)
{
    int i, j;
    int target, tnum, node;
    int num;
    int graph[100][100] = {0};

    scanf("%d", &num);

    for (i = 0; i < num; i++) {
        scanf("%d" "%d", &target, &tnum);
        --target;
        for (j = 0; j < tnum; j++) {
            scanf("%d", &node);
            --node;
            graph[target][node] = 1;
        }
    }

    DFS(graph, num);
}

C++: #include<bits/stdc++.h>
using namespace std;
int n,M[101][101];
int visit[101],d[101],f[101],t;
const int WHITE=0;
const int GLAY=1;
const int BLACK=2;

void dfs(int u){
  visit[u]=GLAY;
  d[u]=++t;
  for(int v=0;v<n;v++){
    if(M[u][v]==0) continue;
    if(visit[v]==WHITE){
    dfs(v);
    }
  }
  visit[u]=BLACK;
  f[u]=++t;
}



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

  for(int i=0;i<n;i++){
    cin>>u>>k;
    u--;
    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;
}