Go: package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)
	g := make([][]int, n+1)
	for i := 0; i < n; i++ {
		var u,k int
		fmt.Scan(&u)
		fmt.Scan(&k)
		g[u] = make([]int, k)
		for j := 0; j < k; j++ {
			fmt.Scan(&g[u][j])
		}
	}

	d := make([]int, n+1)
	f := make([]int, n+1)
	t := 1
	for i := 1; i <= n; i++ {
		t = dfs(&g, &d, &f, i, t)
	}

	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, d[i], f[i])
	}
}

func dfs(g *[][]int, d *[]int, f *[]int, id int, t int) int {
	if (*d)[id] > 0 {
		return t
	}
	(*d)[id] = t
	t += 1
	for i := 0; i < len((*g)[id]); i++ {
		t = dfs(g, d, f, (*g)[id][i], t)
	}
	(*f)[id] = t
	return t+1
}

C++: #include <iostream>
#include<stdio.h>
#include<stack>

#define MAX 100
#define WHITE 1
#define GRAY 2
#define BLACK 3

using namespace std;

int color[MAX], d[MAX], f[MAX];
int n, A[MAX][MAX];
int tt;

void dfs_visit_1(int u) { //???????????°
    color[u] = GRAY;
    d[u] = ++tt;
    for(int v = 0; v < n; v++) {
        if(A[u][v] == 0) continue;
        if(color[v] == WHITE) dfs_visit_1(v);
    }
    color[u] = BLACK;
    f[u] = ++tt;
}

void dfs_1() { // ???????????°
    for(int i = 0; i < n; i++) {
        color[i] = WHITE;
    }
    tt = 0;
    for(int i = 0; i < n; i++) {
        if(color[i] == WHITE) dfs_visit_1(i);
    }

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

}

int next(int u) {
    for(int v = 0; v < n; v++) {
        if(A[u][v] == 1) {
            /*
            if(color[v] == WHITE) return v;
            else if(color[v] == BLACK) return -1;
            else if(color[v] == GRAY) continue;
            */
            return v;
        }
    }
    return -1;
}

void dfs_visit_2(int u) {
    color[u] = GRAY;
    d[u] = ++tt;
    stack<int> S;
    S.push(u);

    while(!S.empty()) {
        int u = S.top();
        int v = next(u);
        if(v != -1) {
            if(color[v] == WHITE) {
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        }else {
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}


int main()
{
    int u, k, v;
    scanf("%d",&n);

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


    /*
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < n; j++) {
            printf("%d", A[i][j]);
            if(j != n-1) printf(" ");
        }
        printf("\n");
    }
    */

    dfs_1();

    return 0;
}

C++: #include <iostream>
#include <stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

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

int next(int u){
    for (int v = nt[u]; v < n; v++){
        nt[u] = v + 1;
        if (M[u][v]) return v;
    }
    return -1;
}

//DFS with stack
void dfs_visit(int r){
    for (int i=0; i<n; i++) nt[i] = 0;

    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;

    while( !S.empty()){
        int u = S.top();
        int v = next(u);
        if ( v != -1){
            if (color[v] == WHITE){
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        } else { // v == -1
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs(){
    //initialization
    for (int i=0; i<n; i++){
        color[i] = WHITE;
        nt[i] = 0;
    }
    tt = 0;

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

int main(){
    int u, k, v;

    cin >> n;

    for (int i=0; i<n; i++){
        for (int j=0; j<n; j++) M[i][j] = 0;
    }

    for (int i=0; i<n; i++){
        cin >> u >> k;
        u--;
        for (int j=0; j<k; j++){
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }

    dfs();

    return 0;
}

C++: #include <iostream>
using namespace std;
static const int MAX = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
int M[MAX][MAX], n, tt = 0;
int d[MAX], f[MAX], color[MAX];

void dfs(int u)
{
    color[u] = GRAY;
    d[u] = ++tt;
    for (int i = 0; i != n; ++i)
    {
        if (M[u][i] && color[i] == WHITE)
        {
            dfs(i);
        }
    }
    color[u] = BLACK;
    f[u] = ++tt;
}

int main()
{
    int id, m, v;
    cin >> n;
    for (int i = 0; i != MAX; ++i)
    {
        d[i] = 0;
        f[i] = 0;
        color[i] = WHITE;
        for (int j = 0; j != MAX; ++j)
        {
            M[i][j] = 0;
        }
    }
    for (int i = 0; i != n; ++i)
    {
        cin >> id >> m;
        for (int j = 0; j != m; ++j)
        {
            cin >> v;
            M[id-1][v-1] = 1;
        }
    }
    for (int i = 0; i != n; ++i)
    {
        if (color[i] == WHITE) dfs(i);
    }

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

C++: #include <iostream>
using namespace std;
int G[101][101];
int d[101];
int f[101];
bool flag[101];
int n,v,k,p;
int t;

void check(int i){
	if(flag[i])return;
	flag[i]=true;
	t++;
	d[i]=t;
	for(int j=1;j<=n;j++){
		if(G[i][j]==1)check(j);
	}
	t++;
	f[i]=t;
	return;
}


int main(){
	cin >>n;
	for(int i=0;i<n;i++){
		cin >> v>>k;
		for(int j=0;j<k;j++){
			cin >> p;
			G[v][p]=1;
		}
	}
	t=0;
	for(int i=1;i<=n;i++)check(i);
	for(int i=1;i<=n;i++){
		cout << i<< " "<<d[i]<< " "<<f[i] <<endl;
	}
}

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

vector<int> G[102];
int d[102];
int f[102];
bool used[102];


int dfs(int i, int t){
    d[i] = t++;
    used[i] = true;
    for(vector<int>::iterator it = G[i].begin(); it != G[i].end(); ++it){
        if(!used[*it]){
            t = dfs(*it, t);
        }
    }
    
    f[i] = t++;
    return t;
}

int main()
{
    int n,u,k,v;
    cin >> n;
    for(int i = 0; i < n; ++i){
        cin >> u >> k;
        for(int j = 0; j < k; ++j){
            cin >> v;
            G[u].push_back(v);
        }
    }
    int t = 1;
    for(int i = 1; i <= n; ++i){
        if(!used[i]){
            t = dfs(i,t);
        }
    }
    
    for(int i = 1; i <= n; ++i){
        cout << i << ' ' << d[i] << ' ' << f[i] << endl;
    }
}

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

vector<vector<int> > list(100);
vector<vector<int> > timed(100);
int times;
void dfs(int now){
	if(!timed[now].empty())	return;
	timed[now].push_back(times++);
	for(int i=0;i<(int)list[now].size();i++){
		dfs(list[now][i]);
	}
	timed[now].push_back(times++);
}

int main(){
	int n;	cin>>n;
	int id,num,ne;
	for(int i=0;i<n;i++){
		cin>>id>>num;
		id--;
		for(int j=0;j<num;j++){
			cin>>ne;
			list[id].push_back(ne-1);
		}
	}
	times=1;
	for(int i=0;i<n;i++){
		if(timed[i].empty())	dfs(0);
	}
	for(int i=0;i<n;i++){
		cout<<i+1;
		for(int j=0;j<(int)timed[i].size();j++){
			cout<<" "<<timed[i][j];
		}
		cout<<endl;
	}
	return 0;
}

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

int n, u, k, v;
int d[101], f[101];
pair<int, vector<int> > G[101];

int ti = 1;

void dfs(int id) {
	if (d[id]) return ;
	d[id] = ti ++;

	vector<int>& adj = G[id].second;
	for (int i=0; i<(int)adj.size(); ++i) {
		dfs(adj[i]);
	}
	f[id] = ti ++;
}

int main() {
	cin >> n;
	for (int i=0; i<n; ++i) {
		cin >> u >> k;
		G[u].first = u;
		while (k --) {
			cin >> v;
			G[u].second.push_back(v);
		}
	}
	for (int i=1; i<=n; ++i) {
		dfs(i);
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}