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;

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];

// uに隣接するvを番号順に取得
int next(int u){
    for(int v=nt[u]; v<n; v++){ // 訪問した場所は探索しなくていいため、v+1にしている？
        nt[u] = v+1;
        if(M[u][v]) return v;
    }
    return -1;
}

// スタックを用いた深さ優先探索
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(){
    // 初期化
    for(int i=0; i<n; i++){
        color[i] =WHITE;
        nt[i] = 0;
    }
    tt = 0;

    // 未訪問のuを始点として深さ優先探索
    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 argc, char const *argv[])
{
    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--; // 0 origin
        for(int j=0; j<k; j++){
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }

    dfs();

    return 0;
}

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

using namespace std;

int t;
int N;
int d[110], f[110];
vector<vector<int> > adj(110);
void dfs(int cur){
    d[cur] = t;
    t += 1;
    //cerr << "visiting " << cur << " " << t << endl;
    for(int i = 0; i < adj[cur].size(); ++i){
        int dst = adj[cur][i];
        if(d[dst] == 0){
            dfs(dst);
        }
    }
    f[cur] = t;
    t++;
}

int main(){
    cin >> N;
    t = 1;
    int u, k;
    for(int i = 0; i < N; ++i){
        cin >> u >> k;
        for(int j = 0; j < k; j++){
            int v;
            cin >> v;
            adj[u].push_back(v);
        }
        sort(adj[u].begin(), adj[u].end());
    }
    dfs(1);
    for(int i = 1; i < N+1; ++i){
        cout << 1 << " " << d[i] << " " << f[i] << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
//#define ll long long
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
#define rep(i, n) REP(i, 0, n)
#define rep_rev(i, n) for (int (i) = (int)(n) - 1 ; (i) >= 0 ; --(i))
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for(int i = x; i < n; i++)
#define all(x) (x).begin(),(x).end()
ll tmp1,tmp2,tmp3;
const ll mod = 1000000007;
const int INF = 1e9;
const ll INFLONG = 1e18;
void swap(ll *x,ll *y){
  ll tmp;
  tmp = *x;
  *x = *y;
  *y = tmp;
}
vector<ll> visited(100,0);
vector<ll> vec[100];
vector<ll> cou_l(100,0);
vector<ll> cou_f(100,0);
ll sum = 0;
void dfs(ll k){
  //cout << k << endl;
  if(visited[k]){return;}
  visited[k] = 1;
  sum++;
  cou_f[k] = sum;
  for(auto itr : vec[k]){
    //cout << itr << endl;
    dfs(itr);
  }
  sum++;
  cou_l[k] = sum;
}
int main(){
  ll n;
  cin >> n;
  ll u,k,v;
  rep(i,n){
    cin >> u >> k;
    u--;
    rep(j,k){
      cin >> v;
      v--;
      vec[u].push_back(v);
    }
  }
  rep(i,n){
    if(visited[i] == 0){
      dfs(i);
    }
  }
  rep(i,n){
    cout << i+1 << " " << cou_f[i] << " " << cou_l[i] << endl;
  }
}

C++: #include<bits/stdc++.h>
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 <bits/stdc++.h>
using namespace std;

using ll = long long;
#define REP(i, n) for(int (i)=0; (i)< (n); ++i)
#define REPR(i, n) for(int (i)=(n); (i)>=0; --i)
#define FOR(i, n, m) for(int (i)=(n); (i)<(m); ++i)

int n;
vector<int> d, f;
vector<vector<int>> g;
int Time = 0;
void dfs(int v){
  d[v] = ++Time;
  REP(i, g[v].size()){
    int nv = g[v][i];
    if(d[nv] != -1) continue;
    dfs(nv);
  }
  f[v] = ++Time;
}

int main(){
  cin >> n;
  d.resize(n,-1), f.resize(n), g.resize(n);
  REP(i, n){
    int u, k;
    cin >> u >> k;
    g[i].resize(k);
    REP(j, k){
      cin >> g[i][j];
      g[i][j]--;
    }
  }
  REP(i, n){
    if(d[i] == -1){
      dfs(i);
    }
  }
  REP(i, n){
    cout << i+1 << " " << d[i] <<" " <<  f[i] << endl;
  }
  return 0;
}