Go: package main

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

const N = 100

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph struct {
	M               [N][N]int
	color, d, f, nt [N]int
	tt              int
}

func (g *Graph) next(u, n int) int {
	for v := g.nt[u]; v < n; v++ {
		g.nt[u] = v + 1
		if g.M[u][v] != 0 {
			return v
		}
	}
	return -1
}

func (g *Graph) dfsVisit(r, n int) {
	var S []int
	S = append([]int{r}, S...)
	g.color[r] = GRAY
	g.tt++
	g.d[r] = g.tt

	for len(S) != 0 {
		u := S[0]
		v := g.next(u, n)
		if v == -1 {
			S = S[1:]
			g.color[u] = BLACK
			g.tt++
			g.f[u] = g.tt
			continue
		}

		if g.color[v] != WHITE {
			continue
		}

		g.color[v] = GRAY
		g.tt++
		g.d[v] = g.tt
		S = append([]int{v}, S...)
	}
}

func (g *Graph) dfs(n int) string {
	for i := 0; i < n; i++ {
		g.color[i] = WHITE
	}
	g.tt = 0

	for u := 0; u < n; u++ {
		if g.color[u] == WHITE {
			g.dfsVisit(u, n)
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d %d %d\n", i+1, g.d[i], g.f[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.dfs(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

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

using namespace std;

const int MAX = 100;

class DFS
{
    vector< vector<int> > adj;
    int num, d[MAX], f[MAX], parent[MAX], status[MAX], tt;

public:
    DFS()
    {
        cin >> num;
        for (int i = 0; i < num; i++)
        {
            d[i] = status[i] = 0;
            parent[i] = -1;
        }

        load(num);
        tt = 0;
    }

    void load(int n)
    {
        int r, c, n_c;
        adj.assign(n, vector<int>());
        for (int i = 0; i < n; i++)
        {
            cin >> r >> n_c;
            adj[r - 1].assign(n_c, int());
            for (int j = n_c - 1; j >= 0; j--)
            {
                cin >> c;
                adj[r - 1].at(j) = c-1;
            }
        }
    }

    int next(int node)
    {
        if (!adj[node].empty())
        {
            int v = adj[node].back();
            adj[node].pop_back();
            return v;
        }
        return -1;
    }

    void run(int node)
    {
        int next_node;
        while (node != -1)
        {
            if (status[node] == 0)
            {
                status[node] = 1;
                d[node] = ++tt;
            }
            next_node = next(node);
            if (next_node == -1)
            {
                status[node] = 2;
                f[node] = ++tt;
                node = parent[node];
                continue;
            }
            if (status[next_node] == 0)
            {
                parent[next_node] = node;
                node = next_node;
            }
        }
    }

    void dfs(){
        for(int node=0;node<num;node++){
            if(status[node] == 0) run(node);
        }
    }

    int dd(int n)
    {
        return d[n];
    }

    int ff(int n)
    {
        return f[n];
    }

    int number()
    {
        return num;
    }
};

int main()
{
    DFS dfs;

    dfs.dfs();
    for (int i = 0; i < dfs.number(); i++)
    {
        cout << i + 1 << " " << dfs.dd(i) << " " << dfs.ff(i) << endl;
    }
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#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){
  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;
  }
}

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;
}

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

#define MAX 100

stack<int> G;
int Graph[MAX+1][MAX+1];
int result[MAX+1][2];
int n;
int cnt = 0;

void dfs(int idx) {
    bool bl = false;
    for(int i=1; i<=n; i++) {
        //もし一つでも残っているノードがあればpushする
        if(Graph[idx][i]==1) {
            for(int j=1; j<=n; j++) {
                Graph[j][i] = 0;
            }
            //cout << "push: " << i << endl;
            cnt++;
            result[i][0] = cnt;
            G.push(i);
            dfs(i);
            bl = true;
        }
    }
    //一つも残っていなかったらpopする
    if(bl==false) {
        //cout << "pop: " << G.top() << endl;
        cnt++;
        result[G.top()][1] = cnt;
        G.pop();
        if(G.empty()) {
            return;
        }
        else {
            dfs(G.top());
        }
    }
}

int main() {
    int idx, g_num, a;

    cin >>n;
    for(int i=0; i<n; i++) {
        cin >> idx >> g_num;
        for(int j=0; j<n; j++) {
            Graph[idx][j] = 0;
        }
        for(int j=0; j<g_num; j++) {
            cin >> a;
            Graph[idx][a] = 1;
        }
    }
    G.push(1);
    cnt++;
    result[1][0] = cnt;
    //cout << "push: " << 1 << endl;
    dfs(1);

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

    return 0;
}

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

int n, u;
int k[101], b[101], d[101], f[101];
int a[101][101];
int t = 1;

void dfs(int v){
    d[v] = t;
    t++;
    b[v]++;
    for(int l=0; l<k[v]; l++){
        if(b[a[v][l]] == 0){
            dfs(a[v][l]);
        }
    }
    f[v] = t;
    t++;
}


int main() {
    ios::sync_with_stdio(false);
    cin >> n;
    for(int i=0; i<n; i++){
        cin >> u;
        cin >> k[u];
        for(int j=0; j<k[u]; j++){
            cin >> a[u][j];
        }
    }
    for(int v=1; v<=n; v++){
        if(b[v] == 0){
            dfs(v);
        }
        cout << v << " " << d[v] << " " << f[v] << endl;
    }
    return 0;
}