Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

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

void dfs(int cur);
int df[100][2]={};
bool dc[100]={};
bool adj[100][100]={};//初期化を忘れない
int n,u,v,k;
int t = 1;

int main(){
  cin >> n;
  for (int i=0; i<n; i++){
    cin >> u >> k;
    for (int j=0; j<k; j++){
      cin >> v;
      adj[u-1][v-1] = true;
    }
  }
  
 
  dfs(0);
  
  for (int i=0; i<n; i++)
    cout << i+1 << " " << df[i][0] << " " << df[i][1] << endl;

}

void dfs(int cur){
  dc[cur] = true;
  df[cur][0] = t;
  t += 1;
  for (int i=0; i<n; i++){
    if (adj[cur][i] && !dc[i]){
      dfs(i);
    }
  }
  df[cur][1] = t; 
  t += 1;
}

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

using namespace std;

const int max_v = 101;
vector<vector<int> > adj_list;
int d[max_v] = { 0 };
int f[max_v] = { 0 };
int discovered[max_v] = { 0 };
int t = 1;

// Depth-first Search ( Stack implementation)
void DFS(int v)
{
	stack<int> S;
	S.push(v);
	discovered[v] = 1;
	d[v] = t++;
	int i = 0;
	while (!S.empty()) {
		v = S.top();
		if (i < adj_list[v - 1].size()) {
			int u = adj_list[v - 1][i++];
			if (discovered[u] == 0) {
				discovered[u] = 1;
				d[u] = t++;
				S.push(u);
				i = 0;
			}
		}
		else {
			S.pop();
			f[v] = t++;
			i = 0;
		}
	}
}

int main(int argc, char** argv)
{
	// Input
	int n;
	int u, k;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		int v;
		vector<int> adj;
		for (int j = 0; j < k; j++) {
			cin >> v;
			adj.push_back(v);
		}
		adj_list.push_back(adj);
	}

	// Depth-first Search
	for (int i = 1; i <= n; i++) {
		if(discovered[i] == 0)
			DFS(i);
	}

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

	return 0;
}

C++: # include<stdio.h>
using namespace std;

# define WHITE 0
# define GREY  1
# define BLACK 2

int M[100][100];
int color[100], d[100], f[100];
int n, tt = 0;

void dfs_visit(int u) {
	color[u] = GREY;
	d[u] = ++tt;
	for (int v = 0; v < n; v++) {
	    if ( M[u][v] == 0) continue;
		if (color[v] == WHITE)  dfs_visit(v);
	}
	color[u] = BLACK;
	f[u] = ++tt;
}

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

int main() {
    int u, v, k;
	scanf("%d", &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++) {
		scanf("%d %d", &u, &k);
		u--;
		for (int j = 0; j < k; j++) {
			scanf("%d", &v);
			v--;
			M[u][v]++;
		}
	}
	dfs();
	for (u = 0; u < n; u++) {
	    printf("%d %d %d\n", u+1, d[u], f[u]);
	}
	return 0;
}

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

#define WHITE 0
#define GRAY 1
#define BLACK 2

int main ()
{
    int N;
    cin >> N;

    int M[N][N];
    int D[N], F[N], C[N];

    for (int i = 0; i < N; i++)
    {
        D[i] = 0;
        F[i] = 0;
        C[i] = WHITE;
        
        for (int j = 0; j < N; j++)
        {
            M[i][j] = 0;
        }
    }

    for (int i = 0; i < N; i++)
    {
        int u, k;
        cin >> u >> k;
        u--;

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

/*
    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            if (j > 0)
                cout << " ";
            cout << M[i][j];
        }
        cout << endl;
    }
*/
    stack<int> *S = new stack<int>;

    int time = 0;

    S->push(0);
    C[0] = GRAY;
    D[0] = ++time;

    while (S->size() > 0)
    {
        int u = S->top();
        int v = -1;

        // next 
        for (int i = 0; i < N; i++)
        {
            int flag = M[u][i];

            if (flag == 1)
            {
                if (C[i] == WHITE)
                {
                    v = i;
                }
            }
        }

        if (v != -1)
        {
            C[v] = GRAY;
            D[v] = ++time;
            S->push(v);
        }
        else
        {
            S->pop();
            C[u] = BLACK;
            F[u] = ++time;
        }
    }

    for (int i = 0; i < N; i++)
    {
        cout << i + 1 << " " << D[i] << " " << F[i] << endl;
    }
    return 0;
}