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 <stdio.h>

int A[101][101];
int ans[101][3];
int an = 1;

int serch(int a[101][101], int  ni, int n){
  int  j;
  
  for(j=0; j<n; j++){
    if(A[ni][j] == 1){
      judge(j, 1);
      serch(A, j, n);
    }
  }
  judge(ni, 2);
}

int judge(int i, int j){
  if(ans[i][j] == 0){
    ans[i][j] = an;
    an++;
  }
}

int  main(){
  int i, j, k, n, x, y;
  
  scanf("%d", &n);
  
  for(i=0; i<n; i++){
    for(j=0; j<n; j++)
      A[i][j] = 0;
    ans[i][0] = i+1;
  }
  
  for(i=0; i<n; i++){
    scanf("%d %d", &x, &y);
    for(j=0; j<y; j++){
      scanf("%d", &k);
      A[i][k-1] = 1;
    }
  }
  
  judge(0, 1);
  
  for(i=0; i<n; i++){
    if(A[0][i] == 1){
      judge(i, 1);
      serch(A, i, n);
    }
  }
  judge(0, 2);
  
  for(i=0; i<n; i++){
    for(j=0; j<3; j++){
      if(j>0)
        printf(" ");
      printf("%d", ans[i][j]);
    }
    printf("\n");
  }
  
  return 0;
}

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

const int MAX_N = 100;
int to[MAX_N][MAX_N];
int ans[MAX_N][2];
bool visited[MAX_N];
int depth = 1;

void dfs(int x) {
  if (ans[x][0] == -1) ans[x][0] = depth++;
  for (int i=0; to[x][i] != -1 && !visited[to[x][i]]; i++) {
    dfs(to[x][i]);
  }
  if (ans[x][1] == -1) ans[x][1] = depth++;
}

int main() {
  int N;
  cin >> N;
  for (int i=0; i<N; i++) {
    for (int j=0; j<N; j++) {
      to[i][j] = -1;
    }
    ans[i][0] = ans[i][1] = -1;
    visited[i] = false;
  }
  for (int i=0; i<N; i++) {
    int tmp, n;
    cin >> tmp >> n;
    for (int j=0; j<n; j++) {
      int t;
      cin >> t; t--;
      to[i][j] = t;
    }
  }

  visited[0] = true;
  dfs(0);
  for (int i=0; i<N; i++) {
    cout << i+1 << " " << ans[i][0] << " " << ans[i][1] << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

class Graph{
public:
  int v;
  int ftime = -1;
  int ltime = -1;
  vector<int> e;
};
vector<Graph> g;
int cnt = 0;
void dfs(int pos){
  if( g[pos].ftime != -1 ) return;
  cnt++;
  g[pos].ftime = cnt;
  for(int i=0; i<g[pos].e.size(); i++){
    dfs(g[pos].e[i]);
  }
  cnt++;
  g[pos].ltime = cnt;
}

int main(void) {

  int n;
  cin >> n;
  g.resize(n);
  int u, k;
  for(int i=0; i<n; i++){
    cin >> u >> k;
    u--;
    g[u].v = u;
    g[u].e.resize(k);
    for(int j=0; j<k; j++){
      cin >> g[u].e[j];
      g[u].e[j]--;
    }
    sort(g[u].e.begin(), g[u].e.end());
  }

  dfs(0);
  for(int i=0; i<n; i++){
    cout << g[i].v + 1 << " " << g[i].ftime << " " << g[i].ltime << endl;
  }



  return 0;
}

// EOF

C++: #include<cstdio>
#include<stack>
using namespace std;
static const int MAXN=101;
static const int INF=(1<<21);
int main(){
	int m[MAXN][MAXN],n,u,k,v,i,j,first[MAXN]={},second[MAXN]={},l,c=1,o;
	stack<int> s;
	bool used[MAXN]={};
	scanf("%d",&n);
	for(i=1;i<n+1;i++){
		for(j=1;j<n+1;j++){
			m[i][j]=INF;
		}
	}
	for(i=0;i<n;i++){
		scanf("%d %d",&u,&k);
		for(j=0;j<k;j++){
			scanf("%d",&v);
			m[u][v]=1;
		}
	}
	s.push(1);
	used[1]=true;
	while(!s.empty()){
		l=s.top();
		if(first[l]==0){
			first[l]=c;
		}
		o=0;
		for(i=1;i<n+1;i++){
			if(m[l][i]==1&&used[i]==false){
				s.push(i);
				o=1;
				used[i]=true;
				break;
			}
		}
		c++;
		if(o==0){
			second[l]=c;
			s.pop();
		}
	}
	for(i=1;i<n+1;i++){
		printf("%d %d %d\n",i,first[i],second[i]);
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int visit[101], d[101], f[101], t;
int n, M[101][101];

static const int WHITE = 0;
static const int GRAY = 1;

void dfs(int u){
    visit[u] = GRAY;
    d[u] = ++t;
    for( int v = 0; v < n; ++v ){
        if(M[u][v] == 0) continue;
        if(visit[v]==WHITE)
            dfs(v);
    }
    f[u] = ++t;
}

int main(){
    int u, v, k;
    cin >> n;
    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] = 1;
        }
    }
    for( int i = 0; i < n; ++i ){
        if(visit[i]==WHITE)
            dfs(i);
    }
    for( int i = 0; i < n; ++i ){
        cout << i+1 <<" "<< d[i] <<" "<< f[i] << endl;
    }
    return 0;
}

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

int n, G[101][101], S[101], T[101];

int dfs(int p, int s) {
    if (S[p] != 0) return 0;
    S[p] = s;
    s++;
    for (int i = 0; i < n; i++) {
        if (G[p][i] == 1) {
            s = max(s, dfs(i, s) + 1);
        }
    }
    T[p] = s;
    return s;
}


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

    s = 0;
    for (int i = 0; i < n; i++)
        if (S[i] == 0) s = dfs(s, i);

    for (int i = 0; i < n; i++)
        printf("%d %d %d\n", i + 1, S[i], T[i]);

    return 0;
}