Go: package main

import "fmt"

type node struct {
	id, d, v int
	adj      []node
}

var n int
var seen []bool
var graph []node

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

func dfs(v, t int) int {
	// fmt.Printf("dfs(v %d, t %d) en:\n", v, t)
	seen[v] = true
	graph[v].v = t
	tt := t
	for _, vv := range graph[v].adj {
		if !seen[vv.id] {
			tt = max(tt, dfs(vv.id, tt+1))
		}
	}
	graph[v].d = tt + 1
	// fmt.Printf("dfs(v %d, t %d) ex: d %d\n", v, t, graph[v].d)
	return graph[v].d
}

func main() {
	fmt.Scan(&n)
	graph = make([]node, n+1)
	for i := 1; i <= n; i++ {
		var u, k, v int
		fmt.Scan(&u, &k)
		graph[u].id = u
		// 頂点uはk個の隣接頂点を持っている
		for j := 0; j < k; j++ {
			fmt.Scan(&v)
			var t node
			t.id = v
			graph[u].adj = append(graph[u].adj, t)
		}
	}
	// fmt.Println("n", n, "graph", graph)
	seen = make([]bool, n+1)
	// t := dfs(1, 1)
	v, t := 1, 1
	done := false
	for !done {
		tt := dfs(v, t)
		done = true
		for i := range seen {
			if !seen[i] {
				done = false
				v = graph[i].id
				t = tt
				break
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, graph[i].v, graph[i].d)
	}
}

C++: 
#include<bits/stdc++.h>

using namespace std;

const int white=0;
const int gray=1;
const int black=2;
const int n=100;

int cnt,m[n][n],color[n],d[n],f[n],tt,nt[n];

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

void dfs_visit(int r)
{
    for(int i=0;i<cnt;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{
            s.pop();
            color[u]=black;
            f[u]=++tt;
        }
    }
}

void dfs()
{
    for(int i=0;i<cnt;i++){
        color[i]=white;
        nt[i]=0;
    }
    tt=0;
    for(int u=0;u<cnt;u++){
        if(color[u]==white){
            dfs_visit(u);
        }
    }
    for(int i=0;i<cnt;i++){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}

int main()
{
    int u,k,v;
    cin>>cnt;
    for(int i=0;i<cnt;i++){
        for(int j=0;j<cnt;j++){
            m[i][j]=0;
        }
    }
    for(int i=0;i<cnt;i++){
        cin>>u>>k;
        u--;
        for(int j=0;j<k;j++){
            cin>>v;
            v--;
            m[u][v]=1;
        }
    }
//    for(int i=0;i<cnt;i++){
//        for(int j=0;j<cnt;j++){
//            cout<<m[i][j]<<" ";
//        }
//        cout<<endl;
//    }
    dfs();
    return 0;
}
/*
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0
*/

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<stack>
using namespace std;
const int MAX=105;
int M[MAX][MAX];
bool vis[MAX];
int n,t=1,d[MAX],f[MAX],nt[MAX];
stack<int> S;
int next(int u){
	for(int v=nt[u];v<=n;v++){
		nt[u]=v+1;
		if(M[u][v])return v;
	}
	return -1;
}
void dfs(int cur){
	memset(nt,0,sizeof(nt));
	vis[cur]=1;
	d[cur]=t++;
	S.push(cur);
	while(!S.empty()){
		int u=S.top();
		int i=next(u);
		if(i!=-1){
			if(M[u][i]&&!vis[i]){
				vis[i]=1;
				d[i]=t++;
				S.push(i);
			}
		}
		else{
			S.pop();
			f[u]=t++;
		}	
	}

}
int main(){
	cin>>n;
	memset(M,0,sizeof(M));
	memset(vis,0,sizeof(vis));
	for(int i=0;i<n;i++){
		int u,k;
		cin>>u>>k;
		int v;
		for(int j=0;j<k;j++){
			cin>>v;
			M[u][v]=1;
		}
	}
	for(int i=1;i<=n;i++){
		if(!vis[i])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 <vector>
#include <stack>
#include <queue>

using namespace std;

static const int N = 100;
static const int NEW = 0;
static const int VISITING = 1;
static const int OLD = 2;

int n, m[N][N] = {0};
int color[N], t1[N], t2[N];

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

int nxt(int idx)
{
	for (int i = 0; i < n; ++i)
	{
		if (m[idx][i] && color[i] == NEW)
			return i;
	}
	return -1;
}

void dfs_visit(int idx)
{
	int t = 1;

	stack<int> s;
	s.push(idx);
	color[idx] = VISITING;
	t1[idx] = t++;

	while (!s.empty())
	{
		int u = s.top();
		int v = nxt(u);
		if (-1 != v)
		{
			color[v] = VISITING;
			t1[v] = t++;
			s.push(v);
		}
		else
		{
			s.pop();
			color[u] = OLD;
			t2[u] = t++;
		}
	}
}

void dfs()
{
	for (int i = 0; i < n; ++i)
		color[i] = NEW;

	for (int i = 0; i < n; ++i)
	{
		if (color[i] == NEW)
			dfs_visit(i);
	}

	for (int i = 0; i < n; ++i)
	{
		cout << i + 1 << " " << t1[i] << " " << t2[i] << endl;
	}
}

int main()
{
	getMatrix();
	dfs();
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const ll INF = 1LL << 60;
const int MAX = 1000000010;
const ll MOD = 1000000007;

int N;
vector<vector<int>> G;
vector<int> d;
vector<int> f;
vector<bool> seen;
int t = 1;

void dfs(int u) {
    seen[u] = true;
    d[u] = t++;

    for (auto nv : G[u]) {
        if (seen[nv]) continue;
        dfs(nv);
    }

    f[u] = t++;
}

int main() {
    cin >> N;
    G.resize(N);
    for (int i = 0; i < N; i++) {
        int u, k; cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            int v; cin >> v;
            v--;
            G[u].push_back(v);
        }
    }
    d.resize(N);
    f.resize(N);
    seen.assign(N, false);

    for (int v = 0; v < N; v++) {
        if (seen[v]) continue;
        dfs(v);
    }

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

C++: #include <stdio.h>
#include <iostream>
#include <stack>
#include <string>
using namespace std;

#define NUM 100
int node_num;
int V[NUM + 1][NUM + 1];
int d[NUM + 1];
int f[NUM + 1];
string color[NUM + 1];
int t;
int pos;
stack<int> s;

void createAdj(int n){
    for(int i = 1; i < NUM; i++){
        for(int j = 1; j < NUM; j++){
            V[i][j] = 0;
        }
    }

    for(int i = 0; i < n; i++){
        int num1;
        scanf("%d", &num1);

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

        int num2;
        for(int j = 0; j < n; j++){
            scanf("%d", &num2);
            V[num1][num2] = 1;
        }
    }
}

int search(int n){
    for(int i = 1; i <= node_num; i++) {
        if(V[n][i] == 1 && color[i] == "white")
            return i;
    }
    return -1;
}

void dfs_init(){
    t = 0;
    for(int i = 0; i < NUM; i++){
        color[i] = "white";
    }
}

void dfs(){
    s.push(1);
    pos = 1;
    t++;
    color[1] = "grey";
    d[1] = t;

    while(s.size()){
        int u = s.top();
        int next_node = search(u);
        if(next_node != -1){
            pos = next_node;
            s.push(next_node);
            pos = next_node;
            t++;
            color[next_node] = "grey";
            d[next_node] = t;
        }else{
            s.pop();
            color[u] = "black";
            t++;
            f[u] = t;
        }
    }
}

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

int main(void){
    scanf("%d", &node_num);
    createAdj(node_num);

    dfs_init();
    dfs();

    print();
}