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

int next(int u);
void dfs_visit(int r);
void dfs();

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

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 i=0;i<n;i++) nt[i] = 0;
	stack<int> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = ++tt;
	while(!S.empty()){
		int u = S.top();
		int v = next(u);
		if(v != -1){
			if(color[v]==WHITE){
				color[v] = GRAY;
				d[v] = ++tt;
				S.push(v);
			}
		}else{
			S.pop();
			color[u] = BLACK;
			f[u] = ++tt;
		}
	}
}

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

C++: # include <iostream>

using namespace std;

struct Vertex
{
    int id, k, *adjcent, start, end;
    bool passed = false;
};

Vertex *vertexs;
int time_ = 0;

void DFS(int now)
{
    vertexs[now].passed = true;
    time_++;
    vertexs[now].start = time_;
    for(int i=0; i<vertexs[now].k; i++)
    {
        if(!vertexs[vertexs[now].adjcent[i]].passed) DFS(vertexs[now].adjcent[i]);
    }
    time_++;
    vertexs[now].end = time_;
}

int main()
{
    int n;
    scanf("%d", &n);
    vertexs = new Vertex[n+1];
    for(int i=1; i<=n; i++)
    {
        scanf("%d%d", &vertexs[i].id, &vertexs[i].k);
        vertexs[i].adjcent = new int[vertexs[i].k];
        for(int j=0; j<vertexs[i].k; j++)
        {
            scanf("%d", &vertexs[i].adjcent[j]);
        }
    }
    for(int i=1; i<=n; i++)
    {
        if(!vertexs[i].passed) DFS(vertexs[i].id);
    }
    for(int i=1; i<=n; i++) printf("%d %d %d\n", vertexs[i].id, vertexs[i].start, vertexs[i].end);

    return 0;
}

C++: #include <iostream>
#define N 110

int t = 1;

int d[N], f[N];
int A[N][N];

void Depth(int id, int n){
  d[id] = t;
  t++;
  for(int i=1; i<=n; i++){
    if(A[id][i] == 1 && d[i] == 0){
      Depth(i, n);
    }
  }
  f[id] = t;
  t++;
}



int main(){
  for(int i=0; i<N; i++){
    d[i]=f[i]=0;
    for(int j=0; j<N; j++){
      A[i][j]=0;
    }
  }
  int n;
  std::cin >> n;
  for(int i=0; i<n; i++){
    int u, k, v;
    std::cin >> u >> k;
    for(int i=0; i<k; i++){
      std::cin >> v;
      A[u][v]=1;
    }
  }
  for(int i=1; i<=n; i++){
    if(d[i] == 0 && f[i] == 0){ Depth(i, n); }
  }
  for(int i=1; i<=n; i++){
    std::cout << i << " " << d[i] << " " << f[i] << std::endl;
  }

  return 0;
}

C++: #include<bits/stdc++.h>

using namespace std;

vector<int> G[110];

int timer;
int d[110],f[110];

bool used[110];

void dfs(int x)
{
    used[x]=true;
    d[x]=++timer;

    for(int i=0;i<G[x].size();i++)
    {
        if(!used[G[x][i]])
        {
            dfs(G[x][i]);
        }
    }

    f[x]=++timer;
}


int main()
{

    int n;

    cin>>n;

    for(int i=0;i<n;i++)
    {
        int a,b,c;

        cin>>a>>b;

        for(int i=0;i<b;i++)
        {
            cin>>c;

            G[a].push_back(c);
        }
    }

    timer=0;
    memset(used,0,sizeof(used));

    for(int i=1;i<=n;i++)
    {
        if(!used[i])
        {
            dfs(i);
        }
    }

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

    return 0;
}

C++: #include <iostream>
#include <stack>
#define MAX 101
#define NIL -1

using namespace std;


int matrix[MAX][MAX] = {0};
int d[MAX], f[MAX];
int n, t;

void dfs();
void dfs_visit(int u);
int next(int u);

int main()
{
	cin >> n;
	
	for (int i = 0; i < n; i++)
	{
		int u, k, v;
		cin >> u >> k;
		for (int j = 0; j < k; j++)
		{
			cin >> v;
			matrix[u][v] = 1;			
		}
	}
	
//显示邻接矩阵 
//	for (int i = 0; i < n; i++)
//	{
//		for (int j = 0; j < n; j++)
//		{
//			if(j) cout << ' ';
//			cout << matrix[i+1][j+1];		
//		}
//		cout << endl;
//	}
	
	
	dfs();
	
	
	for (int i = 1; i <= n; i++)
	{
		cout << i << ' ';
		cout << d[i] << ' ';	
		cout << f[i] << endl;
	}
} 



void dfs()
{	
	for (int i = 1; i <= n; i++)
	{
		if (d[i] == 0)
			dfs_visit(i);
	}
}



void dfs_visit(int u)
{

	stack<int> S;
	S.push(u);
	d[u] = ++t;
	
	while (!S.empty())
	{
		u = next(S.top());
		if (u)
		{
//			if (d[u] == 0)
			{
			d[u] = ++t;
			S.push(u); 				
			}
		}
		else
		{
			f[S.top()] = ++t;
			S.pop();
		}
		
	}
	
}


int next(int u)
{
	for (int i = 1; i <= n; i++)
	{
		if (matrix[u][i] != 0 && d[i] == 0)
			return i;
	}
	return 0;
}