Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) doesAllAdjsVisited(vertices []vertex) bool {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return false
		}
	}
	return true
}

func (v *vertex) isFirstVisit() bool {
	return v.firstVisitAt == 0
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func (v *vertex) nextVertex(vertices []vertex) (vertexId, error) {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return vId, nil
		}
	}
	return vertexId(-1), fmt.Errorf("illegal")
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	timestamp = timestamp + 1
	currentVertex := &vertices[currentId-1]
	if currentVertex.isFirstVisit() {
		currentVertex.firstVisitAt = timestamp
	}
	for !currentVertex.doesAllAdjsVisited(vertices) {
		nextVertexId, _ := currentVertex.nextVertex(vertices)
		timestamp = dfs(nextVertexId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

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

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

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	dfs(vertexId(1), 0, vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

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

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
int a[100],d[100],f[100];
int inf=100000,t=0,n;
int v[100][100];
void dfs(int s){
    d[s]=t++;
    a[s]=inf;
    for(int i=0;i<n;i++){
        if(v[s][i]==1&&a[i]!=inf){
            //cout<<s<<" "<<i<<endl;
            dfs(i);
        }
    }
    f[s]=t++;
}
int main(){
  cin>>n;
  for(int i=0;i<n;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0;j<k;j++){
      int tmp;
      cin>>tmp;
      v[u-1][tmp-1]=1;
    }
  }
  dfs(0);
  for(int i=0;i<n;i++)
      if(!a[i])dfs(i);
  for(int i=0;i<n;i++){
        cout<<i+1<<" "<<d[i]+1<<" "<<f[i]+1<<endl;
  }
}

C++: #define scanf_s scanf
#include <string>
#include <stdio.h>
#include <math.h>
#include <stack>
#include <queue>
#include <list>
#include <vector>
#include <iostream>
using namespace std;

#define MAX 100
//#define MAX_ 1000
struct Graph
{
	int id, k = 0;
	list<int> node;
	int d = 0, f = 0;
};
Graph G[MAX];
int cou = 1;
void Depth(Graph *g)
{
	if (g->k >= 0) {
		if (g->d)
			return; 
		
		g->d = cou;
		++cou;
		for (auto i = g->node.begin(); i != g->node.end(); ++i) {
			Depth(&G[*i]);
		}
		g->f = cou;
		++cou;
		
	}
}

int main(void)
{
	int n, u, xk, v;
	scanf_s("%d", &n);
	for (int i = 0; i < n; ++i) {
		scanf_s("%d %d", &u, &xk);
		G[u - 1].id = u - 1;
		G[u - 1].k = xk;
		for (int j = 0; j < xk; ++j) {
			scanf_s("%d", &v);
			G[u - 1].node.push_back(v - 1);
		}
	}
	for (int i = 0; i < n; ++i) {
		if (G[i].d == 0 && G[i].f == 0) 
			Depth(&G[i]);
		
	}
	for (int i = 0; i < n; ++i) {
		printf("%d %d %d\n", G[i].id + 1, G[i].d, G[i].f);
	}
}

C++: #include<iostream>
#include<cstdio>
#include<stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
static const int NIL = -1;

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

//u に隣接するvを番号順に取得
int next(int u){
    for(int v = nt[u]; v < n; v++){
        nt[u] = v + 1;
        if( M[u][v] ) return v; 
    }
    return NIL;
}

void dfs_visit(int r){
    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;

    while(S.size() != 0){
        int u = S.top();
        int v = next(u);
        if(v != NIL){
            if(color[v] == WHITE){
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs_init(){
    for(int i = 0; i < n; i++){
        color[i] = WHITE;
        nt[i] = 0;
    }
    tt = 0;

    //未訪問のuを始点として深さ優先探索
    for(int u = 0; u < n; u++){
        if(color[u] == WHITE) dfs_visit(u);
    }
    for(int i = 0;i < n; i++){
        cout << i + 1 << " " << d[i]  << " " << f[i] << endl;
    }
}

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

    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            M[i][j] = 0;
        }
    }
    for(int i = 0; i < n; i++){
        scanf("%d %d", &u, &k);
        for(int j = 0; j < k; j++){
            scanf("%d", &v);
            M[u-1][v-1] = 1;
        }
    }

    dfs_init();

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <stack>
#include <utility>

using vvb = std::vector<std::vector<bool>>;

struct TimeStamp
{
    int discovered;
    int finished;
};

std::vector<TimeStamp> dfs(const vvb& edges)
{
    using namespace std;

    int time {1};
    const int n = edges.size();
    stack<int> st;
    vector<bool> reached(n);
    vector<TimeStamp> times(n);

    //すべての辺について行う
    for (int i = 0; i < n; ++i)
    {
        if (reached[i])
            continue;

        times[i].discovered = time++;
        st.push(i);
        
        //点iからつながるすべての辺を調べる
        while (!st.empty())
        {
            int top = st.top();
            for(int i = 0; i < n; ++i)
                if (!reached[i] && edges[top][i])
                {
                    reached[i] = true;
                    times[i].discovered = time++;
                    st.push(i);
                    break;
                }

            //その点からの探索候補がなければ前の点に戻る
            if (top == st.top())
            {
                times[top].finished = time++;
                st.pop();
            }
        }
    }

    return times;
}

void solve()
{
    using namespace std;

    int n;
    cin >> n;

    vvb edges(n, vector<bool>(n));

    //読み込み
    for (int i = 0; i < n; ++i)
    {
        int u, k;
        cin >> u >> k;

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

    auto times = dfs(edges);

    for (int i = 0; i < n; ++i)
    {
        cout << i + 1 << " " << times[i].discovered << " " << times[i].finished << endl;
    }
}

int main()
{
    solve();
    return 0;
}