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 <iostream>
#include <stack>
using namespace std;

#define MAX 100

stack<int> G;
int Graph[MAX+1][MAX+1];
int result[MAX+1][2];
int n;
int cnt = 0;

void dfs(int idx) {
    bool bl = false;
    for(int i=1; i<=n; i++) {
        //もし一つでも残っているノードがあればpushする
        if(Graph[idx][i]==1) {
            Graph[idx][i] = 0;
            //cout << "push: " << i << endl;
            cnt++;
            result[i][0] = cnt;
            G.push(i);
            dfs(i);
            bl = true;
        }
    }
    //一つも残っていなかったらpopする
    if(bl==false) {
        //cout << "pop: " << G.top() << endl;
        cnt++;
        result[G.top()][1] = cnt;
        G.pop();
        if(G.empty()) {
            return;
        }
        else {
            dfs(G.top());
        }
    }
}

int main() {
    int idx, g_num, a;

    cin >>n;
    for(int i=0; i<n; i++) {
        cin >> idx >> g_num;
        for(int j=0; j<n; j++) {
            Graph[idx][j] = 0;
        }
        for(int j=0; j<g_num; j++) {
            cin >> a;
            Graph[idx][a] = 1;
        }
    }
    G.push(1);
    cnt++;
    result[1][0] = cnt;
    cout << "push: " << 1 << endl;
    dfs(1);

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

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using msi = map<string, int>;
using mii = map<int, int>;
using psi = pair<string, int>;
using pii = pair<int, int>;
using vlai = valarray<int>;
#define rep(i,n) for(int i=0;i<n;i++)
#define range(i,s,n) for(int i=s;i<n;i++)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fs first
#define sc second
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define INF 1E9
#define EPS 1E-9
#define MOD (1E9+7)
#define PI 3.1415926535897932384626433832795

std::ostream &operator<<(std::ostream &out, const vector<int> &tgt)
{
	string s;
	for (int i = 0; i<tgt.size(); i++) {
		s += (to_string(tgt[i]) + ((i != tgt.size() - 1) ? " " : ""));
	}
	out << s;
	return out;
}
struct node {
	vi to;
	int fi = -1, se = -1;
	bool visited = false;
};

vector<node> g;
int t = 0;

void dfs(int n) {
//	stack<int> s;
//	s.push(n);
//	while (!s.empty()) {
	g[n].fi = ++t;
	g[n].visited = true;
	rep(i, g[n].to.size()) {
		if(!g[g[n].to[i]].visited)dfs(g[n].to[i]);
	}
	g[n].se = ++t;
}

int main(){
	int n,in,inn;
	cin >> n;
	g.resize(n);
	rep(i, n) {
		cin >> in;
		cin >> in;
		rep(j, in) {
			cin >> inn;
			g[i].to.push_back(inn-1);
		}
	}
	rep(i, n) {
		if (!g[i].visited) {
			dfs(i);
		}
	}
	rep(i, n) {
		cout <<i+1<<" "<< g[i].fi << " " << g[i].se << endl;
	}
}

C++: //#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
const int INF = 100010001;
const ll LINF = (ll)INF*INF*10;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vvi G(n);
    rep(i, n) {
        int u;
        cin >> u;
        --u;
        int k;
        cin >> k;
        rep(j, k) {
            int v;
            cin >> v;
            --v;
            G[u].push_back(v);
        }
    }

    vi d(n), f(n);
    int time = 0;
    function<void(int)> dfs = [&](int i) {
        for(int ne:G[i]) {
            if(d[ne]) continue;
            d[ne] = ++time;
            dfs(ne);
            f[ne] = ++time;
        }
    };
    rep(i, n) {
        if(d[i] == 0) {
            d[i] = ++time;
            dfs(i);
            f[i] = ++time;
        }
    }

    rep(i, n) {
        cout << i+1 << ' ' << d[i] << ' ' << f[i] << '\n';
    }
}

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;
}

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{
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs(){
    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;
int a[120][120],b[120][2],u,k,v,n,cou=1;
void dfs(int i){
  b[i][0]=cou;
  cou++;
  for(int j=1;j<=n;j++){
    if(a[i][j]==1&&b[j][0]==0)dfs(j);
  }
  b[i][1]=cou;
  cou++;
}

int main(){
  cin>>n;
  for(int i=0;i<=n;i++){
    for(int j=0;j<=n;j++){
      a[i][j]=0;
      b[i][0]=0;
      b[i][1]=0;
    }
  }
  for(int i=1;i<=n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v;
      a[u][v]=1;
    }
  }
  for(int i=1;i<=n;i++){
    if(b[i][0]==0)dfs(i);
  }
  for(int i=1;i<=n;i++){
    cout<<i<<" "<<b[i][0]<<" "<<b[i][1]<<endl;;
  }
  return 0;
}

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

using namespace std;

const int MAX = 101;

vector<int> G[MAX];
int d[MAX], f[MAX];
int *T;

void dfs(int u) {

    if (!d[u]) d[u] = *T;

    for (int v : G[u]) {
        if (!d[v]) d[v] = ++(*T);
        dfs(v);
    }

    if (!f[u]) f[u] = ++(*T);
}

int main() {

    int n;
    cin >> n;

    int t = 1;
    T = &t;
    fill(d, d + MAX, 0);
    fill(f, f + MAX, 0);

    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            G[u].push_back(v);
        }
    }

    dfs(1);

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