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;
const int MAXN =  100+7;
struct node {
    int id;
    node* next;
};
node* g[MAXN];
bool visit[MAXN];
int d[MAXN];
int f[MAXN];
int mytime;
stack<int> s;
void dfs(int i){
    node* p = g[i];
    while(p->next!=NULL){
        p=p->next;
        if(visit[p->id]==false){
            s.push(p->id);
            mytime++;
            d[p->id] = mytime;
            visit[p->id] = true;
            dfs(p->id);
        }

    }
    s.pop();
    mytime++;
    f[i] = mytime;

}
int main() {
//    freopen("../in.txt", "r", stdin);
    memset(visit, false, sizeof(visit));
    int n;
    scanf("%d", &n);
    int i;
    for(i = 1; i <= n; i++) {
        g[i] = (node*)malloc(sizeof(node));
        g[i]->next = NULL;
    }
    for(i = 0; i < n; i++) {
        int num;
        int k;
        scanf("%d", &num);
        scanf("%d", &k);
        int j;
        for(j = 0; j < k; j++) {
            int r;
            scanf("%d", &r);
            node* t = (node*)malloc(sizeof(node));
            t->id = r;
            t->next = NULL;
            node* p = g[num];
            while(p->next != NULL) p = p->next;
            p->next = t;
        }
    }
    mytime = 0;
    while(true){
        int u;
        int g = -1;
        for(u = 1; u <= n; u++){
            if(visit[u]==false){
                g = u;
                break;
            }
        }
        if(g==-1){
            break;
        }
        s.push(g);
        mytime++;
        d[g] = mytime;
        visit[g] = true;
        dfs(g);
    }

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

C++: #include <bits/stdc++.h>
#define rep(i, a, b) for (int i = a; i < (b); i++)
#define rrep(i, a, b) for (int i = a; i >= (b); i--)
#define all(x) (x).begin(), (x).end()
using namespace std;
using ll = long long;
using P = pair<int, int>;
template <class T>
inline bool chmin(T& a, T b) {
   if (a > b) {
      a = b;
      return true;
   }
   return false;
}
template <class T>
inline bool chmax(T& a, T b) {
   if (a < b) {
      a = b;
      return true;
   }
   return false;
}
const int INF = 2e9;
const int MOD = 1e9 + 7;

int main() {
   int n;
   cin >> n;
   vector<vector<int>> to(n);
   rep(i, 0, n) {
      int u, k;
      cin >> u >> k;
      u--;
      rep(j, 0, k) {
         int v;
         cin >> v;
         v--;
         to[u].push_back(v);
      }
   }
   vector<int> d(n), f(n), color(n);
   int t = 0;
   function<void(int)> dfs = [&](int u) {
      if (color[u] != 0) return;
      color[u] = 1;
      d[u] = ++t;
      for (int i = 0; i < to[u].size(); i++) {
         if (color[to[u][i]] == 0) {
            dfs(to[u][i]);
         }
      }
      color[u] = 2;
      f[u] = ++t;
   };
   rep(i, 0, n) dfs(i);
   rep(i, 0, n) printf("%d %d %d\n", i + 1, d[i], f[i]);
   return 0;
}

C++: #include <iostream>

#define N_MAX 100

using namespace std;

int t = 1;
int adj_matrix[N_MAX][N_MAX];
int d[N_MAX];
int f[N_MAX];

void dfs(int v, int n)
{
    if (d[v] == 0) {
        d[v] = t;
        t++;
    }
    for (int i = 0; i < n; i++) {
        if (adj_matrix[v][i] != 0) {
            dfs(i, n);
        }
    }
    if (f[v] == 0) {
        f[v] = t;
        t++;
    }
}

int main()
{
    int n, u, k, v;
    cin >> n;
    for (int i = 0; i < n; i++) {
        d[i] = 0;
        f[i] = 0;
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            adj_matrix[i][j] = 0;
        }
    }

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

    dfs(0, n);

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

    return 0;
}

C++: #include <iostream>

using namespace std;

int n;
int A[110][110];
int d[110];
int f[110];
string color[110];
int t = 0;

void dfs_visit(int u) {
  color[u] = "GRAY";
  d[u] = ++t;
  for (int v = 0; v < n; v++) {
    if (A[u][v] == 1 && color[v] == "WHITE") {
      dfs_visit(v);
    }
  }
  color[u] = "BLACK";
  f[u] = ++t;
}

void dfs() {
  // color 初期化
  for (int i = 0; i < n; i++) {
    color[i] = "WHITE";
  }
  for (int u = 0; u < n; u++) {
    if (color[u] == "WHITE") {
      dfs_visit(u);
    }
  }
}

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

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