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 <cstdio>
#include <cstring>
#include <stack>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int d[maxx], f[maxx];
int flag[maxx];
int nowtime = 1;

void dfs(int u) {

	// ??\?????¶??´
	flag[u] = 1;
	d[u] = nowtime++;
	for (int i = 1; i <= n; i++) {
		if (flag[i] == 0 && m[u][i] == 1) {
			dfs(i);
		}
	}
	//????????¶??´
	f[u] = nowtime++;
}

int main()
{

	scanf("%d", &n);
	memset(m, 0, sizeof(m));
	memset(f, 0, sizeof(f));
	for (int i = 1; i <= n; i++) {
		scanf("%d %d", &u, &num);
		for (int j = 1; j <= num; j++) {
			scanf("%d", &v);
			m[u][v] = 1;
		}
	}
	for (int i = 1; i <= n; i++) {
		if(flag[i] == 0)
			dfs(i);
	}
	for (int i = 1; i <= n; i++) {
		printf("%d %d %d\n", i, d[i], f[i]);
	}
	return 0;
}

C++: #include<iostream>
#include<cstring>
#include<vector>
#define rep(i, n) for (int i = 0; i < n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; i--)
using namespace std;
//using Graph = vector<vector<int>>;
typedef long long ll;
typedef pair<long long,int> P;


int n, t = 0;
vector<int> g[105];
bool seen[105];
int d[105], f[105];

void dfs(int v){
    seen[v] = true;
    d[v] = t;
    for(int nv : g[v]){
        if(seen[nv]) continue;
        t++;
        dfs(nv);
    }
    t++;
    f[v] = t;
}

int main(){
    cin >> n;
    rep(i, n){
        int a, b;
        cin >> a >> b;
        rep(j, b){
            int c;
            cin >> c;
            g[a].push_back(c);
        }
    }
    rep(k, n) g[0].push_back(k + 1);

    memset(seen, 0, sizeof(seen));
    dfs(0);

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

C++: #include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <functional>

using namespace std;
using ll = long long int;
#define rep(i,n) for(int i = 0; i < n; i++)
#define FOR(i, a, b)  for(int i = (a); i < (b) ; i++)

#define pb push_back
#define SORT(v,n) sort(v, v+n)
#define ALL(x) (x).begin(),(x).end()
#define debug(x) cerr << #x << ": " << x << '\n'
#define elif else if
#define itn ll
#define int ll
const int INF = 100100100;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
///                →,↑,←,↓,↗,↖,↙,↘
int dx[8] = { 1, 0, -1, 0, 1, -1, -1, 1 };
int dy[8] = { 0, 1, 0, -1, 1, 1, -1, -1 };

static const int N = 100;
static const int White = 0;
static const int Gray = 1;
static const int Black = 2;
int d[N], f[N],tt;
int color[N],n,M[N][N];


void dfs_visit(int u) {
	int v;
	d[u] = ++tt;
	color[u] = Gray;
	rep(v,n){
		if (M[u][v] == 0) continue;
		if (color[v] == White) dfs_visit(v);
	}
	color[u] = Black;
	f[u] = ++tt;
}

void dfs() {
	int u;
	rep(u, n)color[u] = White;
	rep(u, n) {
		if (color[u] == White) dfs_visit(u);
	}
	rep(u, n) {
		cout << u + 1 << ' ' << d[u] << ' ' << f[u] << '\n';
	}
}

signed main() {
	ios::sync_with_stdio(false);
	cin >> n;
	int i;
	rep(i, n) {
		int u, k, v;
		cin >> u >> k;
		u--;
		int j;
		rep(j, k) {
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}
	dfs();
	return 0;
}

C++: #include <stdio.h>
int n,M[100][100],C[100],d[100],f[100],t;
void visit(int );
void dfs();
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();
  return 0;
}
void dfs(){
  int i;
  for(i=0;i<n;i++)C[i]=0;
  t=0;
  for(i=0;i<n;i++)if(C[i]==0)visit(i);
  for(i=0;i<n;i++)printf("%d %d %d\n",i+1,d[i],f[i]);
}
void visit(int k){
  int i;
  C[k]=1;
  d[k]=++t;
  for(i=0;i<n;i++){
    if(M[k][i]==0)continue;
    if(C[i]==0)visit(i);
  }
  C[k]=2;
  f[k]=++t;
}

C++: #include <stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

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

void dfs_visit(int u){
    int v;
    color[u] = GRAY;
    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;
    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(void){
    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 <iostream>
#include <vector>
using namespace std;
using Graph = vector<vector<int>>;

// 深さ優先探索
vector<bool> seen;
vector<int> start_ptr;
vector<int> end_ptr;
void dfs(const Graph &G, int v, int &ptr) {
    seen[v] = true;
    start_ptr[v]=ptr;
    ptr++;
    for (auto next_v : G[v]) { 
        if (seen[next_v]) continue;
        dfs(G, next_v, ptr); // 再帰的に探索
    }
    end_ptr[v]=ptr;
    ptr++;
}

int main() {
    // 頂点数と辺数
    int N; cin >> N;

    // グラフ入力受取
    Graph G(N);
    for (int i = 0; i < N; ++i) {
        int a, b;
        cin >> a >> b;
        for(int j=0;j<b;j++){
            int v; cin >>v;
        
        G[a-1].push_back(v-1);
        }
    }

    // 全頂点が訪問済みになるまで探索
    seen.assign(N, false);
    int ptr=1;
    start_ptr.resize(N);
    end_ptr.resize(N);
    for (int v = 0; v < N; ++v) {
        if (seen[v]) continue; // v が探索済みだったらスルー
        dfs(G, v, ptr); // v が未探索なら v を始点とした DFS を行う
    }
    for(int i=0;i<N;i++){
    cout << i+1 <<" "<<start_ptr[i]<<" "<<end_ptr[i]<< endl;
    }
}