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++: #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);
}