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>
#include<cassert>
using namespace std;

void dfs(int cur);

int A[100][100], d[100], f[100];;
int n,t=0;

int main()
{
    	cin>>n;
        
    	for(int i=0;i<n;++i){

		d[i]=0;
		f[i]=0;

        	for(int j=0;j<n;++j){
            		A[i][j]=0;
        	}
        
        	int m,k; //k=number of adj
        	cin>>m>>k;
        	assert(m==i+1);
        
        	for(int j=0;j<k;++j){
            		int adj;
            		cin>>adj;
            		if(adj){
                		A[i][adj-1]=1;
            		}
        	}
    	}

	/*
	for(int i=0;i<n;++i){
		for(int j=0;j<n;++j){
			cout<<A[i][j]<<" ";
		}
		cout<<endl;
	}
	*/

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

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

    	return 0;
}

void dfs(int cur)
{
	t+=1;
	d[cur]=t;
	//cout<<"visiting "<<cur+1<<" "<<t<<endl;

	for(int dst=0;dst<n;++dst){
		if(A[cur][dst]==1&&d[dst]==0){
			dfs(dst);
		}
	}

	t+=1;
	f[cur]=t;

	//cout<<"leaving "<<cur+1<<" "<<t<<endl;

	return;
}

C++: #include <cstdio>
using namespace std;
#define MAX_N 100

int graph[MAX_N+1][MAX_N+1];
int d[MAX_N+1];
int f[MAX_N+1];

int n;
int t;
void dfs(int id) {
  if(id != 0)
    t++;
  d[id] = t;
  for(int i=1;i<=n;i++) {
    if(graph[id][i] != 0 && d[i] == 0) {
      dfs(i);
    }
  }
  if(id != 0)
    t++;
  f[id] = t;
}

int main() {
  scanf("%d\n",&n);
  // dummy
  for(int i=0;i<=n;i++) {
    graph[0][i] = 1;
  }
  int u,k,v;
  for(int i=0;i<n;i++) {
    scanf("%d %d ",&u,&k);
    for(int j=0;j<k;j++) {
      scanf("%d ",&v);
      graph[u][v] = 1;
    }
  }

  dfs(0);

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

C++: // 274
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <stack>
using namespace std;

int N;
int G[110][110] = {}; // 隣接リスト表現
int d[101] = {};
int f[101] = {};

int main(void) {

    cin >> N;

    for (int i = 1; i <= N; ++i) {
        int v;
        cin >> v;
        cin >> G[v][0];
        for (int k = 1; k <= G[v][0]; ++k) {
            cin >> G[i][k];
        }
    }

    int time = 0;
    for (int n = 1; n <= N; ++n) {
        if (d[n] == 0) {
            stack<int> S;

            S.push(n);
            
            d[n] = ++time;
            while (!S.empty()) {
                int u = S.top();

                bool found = false;
                // 未探索の奴をスタックに積む
                for (int i = 0; i < G[u][0]; ++i) {
                    if (d[G[u][i + 1]] != 0) continue;
                    S.push(G[u][i + 1]);
                    found = true;
                    d[G[u][i + 1]] = ++time;
                    break;
                }

                if (!found) {
                    f[u] = ++time;
                    S.pop();
                } 
            }
        }
    }


    for (int i = 1; i <= N; ++i) {
        cout << i << ' ' << d[i]  << ' ' << f[i] << endl;
    }
    return 0;
}

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

static const int MAX_NUM = 101;

static const int NO_VISIT  = 0;
static const int NOW_VISIT = 1;
static const int END_VISIT = 2;

void DSF(int* matrix, int num)
{
    int i, j;
    int ttime = 0;
    int stime[MAX_NUM+1] = {0};
    int etime[MAX_NUM+1] = {0};
    int state[MAX_NUM+1] = {0};
    stack<int> S;
    int target, next;
    int *tmp;

    for (j = 1; j <= num; j++) {
    if (state[j] != NO_VISIT) {
        continue;
    }
    S.push(1);
    ++ttime;
    stime[1] = ttime;
    state[1] = NOW_VISIT;

    while (S.empty() == false) {
        target = S.top();
        for (i = 1; i <= num; i++) {
            tmp = matrix + MAX_NUM * target + i;
            if ((*tmp == 1) && (state[i] == NO_VISIT)) {
                *tmp = 2;
                S.push(i);
                ++ttime;
                stime[i] = ttime;
                state[i] = NOW_VISIT;
                break;
            }
        }

        if (i == num + 1) {
            S.pop();
            ++ttime;
            etime[target] = ttime;
            state[target] = END_VISIT;
        }
    }
    }

    for (i = 1; i <= num; i++) {
        printf("%d %d %d\n", i, stime[i], etime[i]);
    }

    return;
}

int main(void)
{
    int i, j;
    int num;
    int elem;
    int nume;
    int tmp;
    int matrix[MAX_NUM][MAX_NUM] = {0};

    scanf("%d", &num);

    for (i = 0; i < num; i++) {
        scanf("%d %d", &elem, &nume);
        for (j = 0; j < nume; j++) {
            scanf("%d", &tmp);
            matrix[elem][tmp] = 1;
        }
    }

    DSF(&matrix[0][0], num);

    return 0;
}