Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

C++: #include<bits/stdc++.h>
//cout<<setprecision(1)<<fixed<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int MAX_N=100000;
const int INF = 0x3f3f3f3f;
#define eps 1e-7
//#define Kongxiangzhouye
int n;
int a[123][123];
int st[123];
int ed[123];
int now;
void dfs(int local){
	st[local]=now++;
	for(int i=1;i<=n;i++){
		if(a[local][i]){
			if(st[i]==0){
				dfs(i);
			}
		}
	}
	ed[local]=now++;
}
int main(){
	ios::sync_with_stdio(false);
	while(cin>>n){
		memset(a,0,sizeof(a));
		memset(st,0,sizeof(st));
		memset(ed,0,sizeof(ed));
		for(int i=0;i<n;i++){
			int t,m;
			cin>>t>>m;
			for(int i=0;i<m;i++){
				int te;
				cin>>te;
				a[t][te]=1;
			}
			now=1;
		}
		for(int i=1;i<=n;i++){
			if(!st[i])
				dfs(i);
		}
		for(int i=1;i<=n;i++){
			cout<<i<<" "<<st[i]<<" "<<ed[i]<<endl;
		}
	}
	return 0;
}

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

int visit[100],end[100],a[100][100];
int t,N,u,k,col;

void rist_to_mat(int N) {
	for(int l=0; l<N; ++l) {
		cin >> u >> k;
		for (int i=0; i<k; ++i) {
			cin >> col;
			a[u-1][col-1] = 1;
		}
	}
}

void dfs(int cur,int N) {
	t += 1;
	visit[cur] = t;
	for(int dst=0; dst<N; ++dst) {
		if(a[cur][dst] == 1 && visit[dst] == 0) {
			dfs(dst,N);
		}
	}
	t += 1;
	end[cur] = t;
}

int main() {
	cin >> N;
	rist_to_mat(N);
	for(int i=0; i<N; ++i) {
		if(visit[i] == 0) dfs(i,N);
	}
	for(int i=0; i<N; ++i) {
		cout << i+1 << ' ' << visit[i] << ' ' << end[i] << endl;
	}
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include<cstdio>

bool table[102][102] = {};
int color[102] = {}; //0:?????¢?´¢???1:?¨??????????, 2:??¢?´¢??????
int n, counter = 0;
int t_visit[102] = {};
int t_finish[102] = {};

void DFS(int y) {
	
	for (int j = 0; j <= n - 1;j++) {

		//?¨????or??¢?´¢???????????£???????????????
		if ((table[y][j] == 1)&&(color[j] == 0)) {
			color[y] = 1; //?¨???????????????????
			if (t_visit[y] == 0) t_visit[y] = ++counter;
			DFS(j);
		}

	}

	color[y] = 2; //??¢?´¢???????????????
	if (t_visit[y] == 0) t_visit[y] = ++counter;
	if (t_finish[y] == 0) t_finish[y] = ++counter;
	
}

int main(void) {
	int u, k, s;

	scanf("%d", &n);

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


	for (int i = 0;i <= n - 1;i++) {
		if (color[i] == 0) {
			DFS(i);
		}
	}


	for (int i = 0; i <= n - 1;i++) {
		printf("%d %d %d\n", i + 1, t_visit[i], t_finish[i]);
	}

	return 0;
}

C++: #include <iostream>
#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;

int n, time1=0, M[N][N], color[N];
int nt[N], begin[N], end[N];

int next(int r)
{
	int i;
	for(i=nt[r]; i<n; i++)
	{
		nt[r]=i+1;
		if(M[r][i]==0)
			continue;
		if(color[i]==WHITE)
			return i;
	}
	return -1;
	
}

void dfs_visit(int r)
{
	int i, j;
	stack<int> S;
	S.push(r);
	color[r]=GRAY;
	begin[r]=++time1;
	
	while(!S.empty())
	{
		int u=S.top();
		int v=next(u);
		if(v!=-1)
		{
			begin[v]=++time1;
			color[v]=GRAY;
			S.push(v);
		}
		else
		{
			S.pop();
			color[u]=BLACK;
			end[u]=++time1;
		}

	}
}

void dfs()
{
	int i, j;
	for(i=0; i<n; i++)
	{
		color[i]=WHITE;
		nt[i]=0;
	}

	for(i=0; i<n; i++)
	{
		if(color[i]==WHITE)
		{
			dfs_visit(i);
		}
	}
	for(i=0; i<n; i++)
	{
		cout<<i+1<<" "<<begin[i]<<" "<<end[i]<<endl;
	}
}

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

	dfs();
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>

using namespace std;

#define FIND 0
#define END 1

int  N;
bool Path[101][101] = {false};
int  TIME[101][2] = {0};
int time_tt;


void DFS(int i){
    if(!(TIME[i][FIND])) {
        time_tt++;
        TIME[i][FIND] = time_tt;
    }
    
    for (int p = 1; p <= N; p++) {
        if (Path[i][p]) DFS(p);
    }
    
    if(!(TIME[i][END])) {
        time_tt++;
        TIME[i][END] = time_tt;
    }
}

int main(){
    cin >> N;
    int bb;
    for (int i = 1; i <= N; i++) {
        int K;
        scanf("%d %d",&bb,&K);
        for (int k = 0; k < K; k++) {
            int p;
            scanf("%d",&p);
            
            Path[i][p] = true;
        }
    }
    
    time_tt = 0;
    
    DFS(1);
    
    for (int i = 1; i <= N; i++) {
        printf("%d %d %d\n",i,TIME[i][FIND],TIME[i][END]);
    }
    
    return 0;
}