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+1)
	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 <bits/stdc++.h>
using namespace std;
#define MAX 10000
#define NIL -1
#define WHITE 0
#define GRAY 1
#define BLACK 2
static const int N = 100;
static const int INFTY = 10000000;

int n,M[N][N];
int color[N],d[N],f[N],tt;

void dfs_visit(int u){
  int v;
  color[u] = GRAY;
  tt++;
  d[u] = tt;
  for( v = 0;v<n;v++){
    if(M[u][v] ==0) continue;
    if(color[v] == WHITE){
      dfs_visit(v);
    }
  }
  color[u] = BLACK;
  tt++;
  f[u] = tt;
}
void dfs(){
  int u;
  for(u =0;u<n;u++) color[u] = WHITE;
  tt = 0;
  
  for(u= 0;u<n;u++){
    if(color[u] == WHITE) dfs_visit(u);
  }
  for(u = 0;u<n;u++){
    printf("%d %d %d\n",u+1,d[u],f[u]);
  }
}


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

}

C++: #include <bits/stdc++.h>
using namespace std;
template <class T>
bool chmax(T& a, const T& b)
{
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
bool chmin(T& a, const T& b)
{
    if (b < a) {
        a = b;
        return 1;
    }
    return 0;
}

#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define all(x) (x).begin(), (x).end() //sortなどの引数を省略したい
#define F first
#define S second

typedef long long ll;
const ll MOD = 1e9 + 7;
const int inf = 1000000;
const int minf = -1000000;
const ll lnf = 1e12;
const ll mlnf = -1e12;
const double e = 1e-10;

using Graph = vector<vector<int>>;

// global variery
int N;
int d[110];
int f[110];
int ans;

void solve();
void dfs(const Graph& G, int v);

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    solve();
    return 0;
}

void solve()
{
    cin >> N;
    Graph G(N);
    rep(i, N)
    {
        int hoge;
        cin >> hoge;
        int k;
        cin >> k;
        rep(j, k)
        {
            int tmp;
            cin >> tmp;
            tmp--;
            G[i].push_back(tmp);
        }
    }
    rep(i, N) d[i] = -1;
    rep(i, N) f[i] = -1;
    ans = 0;

    rep(i, N)
    {
        if (d[i] != -1)
            continue;
        ans++;
        dfs(G, i);
    }
    rep(i, N)
    {
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
    return;
}

void dfs(const Graph& G, int v)
{
    d[v] = ans;
    for (auto nv : G[v]) {
        if (d[nv] != -1)
            continue;
        ans++;
        dfs(G, nv);
    }
    ans++;
    f[v] = ans;
}

C++: #include <bits/stdc++.h>
using namespace std;
vector<int> d;
vector<int> f;
vector<bool> used;
vector< vector<int> > v;
int n;
int cnt = 1;
 
void dfs(int pos){
  d[pos] = cnt; cnt++;
  used[pos] = true;
  for(int i = 0; i < n; i++){
    if(v[pos][i] && !used[i]){
      dfs(i);
    }
  }
  f[pos] = cnt; cnt++;
}
 
int main(void){
  ios::sync_with_stdio(false);
  cin.tie(0);
 
  cin >> n;
  d = f = vector<int>(n, -1);
  used = vector<bool>(n, false);
  v = vector< vector<int> >(n, vector<int>(n, 0));
  for(int i = 0; i < n; i++){
    int u, k; cin >> u >> k;
    u--;
    for(int j = 0; j < k; j++){
      int a; cin >> a;
      a--;
      v[u][a] = 1;
    }
  }
  for(int i = 0; i < n; i++)
    if(!used[i]) dfs(i);
  for(int i = 0; i < n; i++){
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
 
  return 0;
}

C++: n=int(input())

l=[[0 for i in range(n)] for j in range(n)]##静的確保 隣接行列
d=[0 for i in range(n)]##発見
f=[0 for i in range(n)]##完了
stack=[]##スタック
check=[]

for i in range(n):
    p=[int(x) for x in input().split()]
    
    for j in range(n):
        if j+1 in p[2:]:
            l[i][j]=1
##print("---隣接行列---")
##print(l)

time=1
d[0]=1
stack+=[1]
check+=[-1]

while len(stack)!=0:
    ##print("----------while---------")
    for i in range(n):
        if l[stack[-1]-1][i]==1 and not i+1 in check:
            time+=1
            d[i]=time
            stack+=[i+1]

           ## print("stack:",stack)
           ## print("d[",i,"]:",d[i])
            break
        elif i==n-1:
##最深    
            check+=[stack[-1]]
            time+=1
            f[stack.pop()-1]=time

            ##print("f[",i,"]:",f[i])
            ##print("check:",check)
            


for i in range(n):
    print(i+1," ",d[i]," ",f[i])

C++: #include<stdio.h>

int d[100],f[100],n,g[100][100],time=1;

int func(int n){
    d[n]=time++;
    int i,j;
    for(i=0;i<n;i++){
        if(g[n][i]==1 && d[i]==0){
            func(i);
        }
    }
    f[n]=time++;
}

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