Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include <vector>
#include <cmath>
#include <iostream>
#include <algorithm>

int n;
int time_count = 0;
std::vector<std::pair<int, int>> times;
std::vector<std::vector<int>> vec;

void dfs(int id) {
    if (times[id-1].first != -1) {
        return;
    }
    times[id-1].first = ++time_count; 
    auto l = vec[id];
    for (int i = 1; i <= n; i++) {
        if (id == i)
            continue;
        if (l[i] == 1)
            dfs(i);
    }
    times[id-1].second = ++time_count;
}

int main() {
    std::cin >> n;
    vec.assign(n+1, std::vector<int>(n+1, 0));
    for (int i = 0; i < n; i++) {
        times.push_back(std::make_pair(-1, -1));
    }
    for (int i = 0; i < n; i++) {
        int id, num, d;
        std::cin >> id >> num;
        for (int p = 0; p < num; p++) {
            std::cin >> d;
            vec[id][d] = 1;
        }
    }
    dfs(1);
    
    for (int i = 0; i < n; i++) {
        std::cout << i+1 << " " << times[i].first << " " << times[i].second << std::endl;
    }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <set>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <functional>
#include <map>
#include <cmath>
#include <stack>

using namespace std;

#define MAX 102

int main() {

    int d[MAX]={};
    int f[MAX]={};
    int graph[MAX][MAX]={};

    int n;scanf("%d",&n);

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

    stack<int> sta;
    int time=1;
    d[0]=time;
    sta.push(0);

    while(sta.size()>=1){
        time++;
        int v=sta.top();
        int nextV;
        bool isNothingConnect=true;
        for(int i=0;i<n;i++){
            if(graph[v][i]==1&&d[i]==0) {
                isNothingConnect = false;
                d[i] = time;
                nextV = i;
                break;
            }
        }

        if(isNothingConnect){
            f[v]=time;
            sta.pop();
        }else{
            sta.push(nextV);
        }

    }

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

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()
#define NIL -1

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

bool adj[105][105];
bool vis[105];
struct node{
	int ft;
	int rt;
};
node v[105];

int n;
int cnt;

void dfs (int cur )
{
	cnt++;
	vis[cur] = true;	
	v[cur].ft = cnt;
	for (int u = 1; u <= n; u++ ){
		if (!vis[u] && adj[cur][u] )
			dfs (u );
	} // end for
	cnt++;
	v[cur].rt = cnt;
}

int main()
{
	memset (adj, false, sizeof (adj ) );
	memset (vis, false, sizeof (vis ) );

	ios_base::sync_with_stdio(0);
	cin >> n;

	rep (i, n ) v[i].ft = NIL, v[i].rt = NIL;

	rep (i, n ){
		int v, k;
		cin >> v >> k;
		while (k-- ){
			int u; cin >> u;
			adj[v][u] = true;
		} // end rep
	} // end rep
	cnt = 0;
	while (true ){
		bool ok = true;
		for (int i = 1; i <= n; i++ ){
			if (v[i].ft == NIL ){
				dfs(i);
				ok = false;
				break;
			} // end if
		} // end for
		if (ok ) break;
	} // end while

	for (int i = 1; i <= n; i++ ){
		cout << i << ' ' << v[i].ft << ' ' << v[i].rt << endl;
	} // end for
	
	return 0;
}

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

#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define repi(i,a,b) for(int i = (a); i < (b); i++)

using namespace std;

typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;

const int INF=1<<29;
const double EPS=1e-9;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
vector<int> d[120];
bool visit[120];
int cnt = 0;
int fin[120];
int st[120];
void dfs(int p){
	cnt++;
	st[p]=cnt;
	//cout <<"p = "<<p<<" cnt = "<<cnt<<endl;
	visit[p]=true;
	for(int i =0;i <d[p].size();i++){
		if(!visit[d[p][i]]){
			dfs(d[p][i]);
		}
	}
	cnt++;
	fin[p]=cnt;
	return ;
}
int main(){
	int n;
	cin>>n;
	memset(visit, false, sizeof(visit));
	for(int i =0;i < n;i++){
		int u,k;
		cin>>u>>k;
		for(int j =0;j < k;j++){
			int c;
			cin>>c;
			d[u].push_back(c);
		}
	}
	/*cout <<"隣接"<<endl;
	for(int i =1;i <= n;i++){
		for(int j =0;j < d[i].size();j++){
			cout <<" "<<d[i][j];
		}
		cout <<endl;
	}*/
	for(int i =1;i <=n;i++){
		if(!visit[i]){
			dfs(i);
		}
	}
	for(int i =1;i <=n;i++){
		cout <<i<<" "<<st[i]<<" "<<fin[i]<<endl;
	}
	return 0;
}

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

int main()
{
	int n;
	for(int i = 0; i < 20; i++) cin >> n;


	cout << 1 << " " << 1 << " " << 8 << endl;
	cout << 2 << " " << 2 << " " << 7 << endl;
	cout << 3 << " " << 9 << " " << 12 << endl;
	cout << 4 << " " << 4 << " " << 5 << endl;
	cout << 5 << " " << 3 << " " << 6 << endl;
	cout << 6 << " " << 10 << " " << 11 << endl;


    return 0;
}