Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

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

#define rep(i,n) for(int i = 0; i < n; i++)
#define Rep(i,n) for(int i = 1; i <= n; i++)
#define sz(x) int(x.size())
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define YesorNo(a) printf(a ? "Yes\n" : "No\n")
#define endl '\n'
#define fi first
#define se second
using ll = long long;
using P = pair<int,int>;
using Pl = pair<ll,ll>;
template<class T> using V = vector<T>;
const int dx[] = {0,1,0,-1,1,1,-1,-1};
const int dy[] = {1,0,-1,0,1,-1,-1,1};
const int inf = (1<<30)-1;
const ll infll = (1LL<<62)-1;
ll ceil(const ll &a, const ll &b){return ((a)+(b)-1)/b;}
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }

void dfs(int v, int &t, const V<V<int>> &g, V<P> &time) {

    t++;
    time[v].fi = t;
    for(int nv : g[v]) {
        if(time[nv].fi) continue;
        dfs(nv, t, g, time);
    }
    t++;
    time[v].se = t;
}

int main(){

    int n;
    cin >> n;
    V<V<int>> g(n);
    rep(i,n) {
        int a, k;
        cin >> a >> k;
        a--;
        rep(j,k) {
            int b;
            cin >> b;
            b--;
            g[a].push_back(b);
        }
    }
    V<P> time(n);
    int t = 0;
    rep(i,n) {
        if(time[i].fi) continue;
        dfs(i, t, g, time);
    }
    rep(i,n) {
        printf("%d %d %d\n", i+1, time[i].fi, time[i].se);
    }
}

C++: #include<iostream>
#include<climits>
#include<vector>
#include<list>
#include<functional>
#include<algorithm>
#include<string>
#include<cmath>
#include<complex>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<tuple>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
#define INF (int)1e9
#define INFL (ll)1e11
using namespace std;
typedef long long ll;
typedef pair<int, int> P;

void dfs(int s, vector<vector<int>> a, vector<int> &d, vector<int> &f) {
	int n = a.size();
	int next = -1;
	REP(j, n) {
		if (!d[j] && a[s][j]) {
			if (next == -1) d[j] = d[s] + 1;
			else d[j] = f[next] + 1;
			next = j;
			dfs(j, a, d, f);
		}
	}
	if (next == -1) {
		f[s] = d[s] + 1;
	}
	else {
		f[s] = f[next] + 1;
	}
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int n;
	cin >> n;
	vector<vector<int>> a(n, vector<int>(n, 0));
	REP(i, n) {
		int u, k;
		cin >> u >> k;
		u--;
		REP(j, k) {
			int v;
			cin >> v;
			a[u][--v] = 1;
		}
	}
	vector<int> d(n, 0);
	d[0] = 1;
	vector<int> f(n);
	dfs(0, a, d, f);
	REP(i, n) {
		cout << i + 1 << " " << d[i] << " " << f[i] << "\n";
	}

	return 0;
}

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

#define SIZE 105

using namespace std;

vector<int> v[SIZE];
int step = 1;
int in[SIZE];
int out[SIZE];
bool book[SIZE];

void dfs(int cur) {
	if(book[cur]) return ;
	book[cur] = true;
	in[cur] = step++;
	for(int i = 0; i < v[cur].size(); i++) dfs(v[cur][i]);
	out[cur] = step++;
}

int main() {
	int n;
	cin >> n;
	
	for(int i = 0; i < n; i++) {
		int id, k;
		cin >> id >> k;
		
		for(int j = 0; j < k; j++) {
			int x;
			cin >> x;
			
			v[id].push_back(x);
		}
		
		sort(v[id].begin(), v[id].end());
	}
	
	dfs(1);

	for(int i = 1; i <= n; i++) 
		if(in[i] != 0) cout << i << " " << in[i] << " " << out[i] << endl;
	
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<bitset>
#include<vector>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<iomanip>
#include <functional>
using namespace std;
typedef long long ll;
const int mod = 1000000007;
const int INF = 1 << 28;
//cout << fixed << std::setprecision(9)
//memset(a, 0, sizeof(a));
//--------------------------

int n;
bool g[110][110];
int d[110];
int f[110];

void dfs(int s)
{
	stack<int> stk;
	d[s] = 0;
	stk.push(s);
	int current = 0;
	while (!stk.empty()) {
		int u = stk.top();
		int flag = 0;
		for (int j = 1; j <= n; j++) {
			if (g[u][j] && d[j] == -1) {
				flag = 1;
				stk.push(j);
				d[j] = ++current;
				break;
			}
		}

		if (flag == 0) {
			f[u] = ++current;
			stk.pop();
		}

	}
}

int main()
{
	cin >> n;
	for (int i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			g[u][v] = true;
		}
	}

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

	dfs(1);

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

	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
#include<stack>
using namespace std;
int main(){
    int n,u,k,v;
    int M[100][100]={0};
    stack<int> S;

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

    int time=0;
    int d[100]={0},f[100]={0};
    bool found;
    int i;

	for(int k=0;k<n;k++){
	    if(d[k]==0) S.push(k);
	    while(!S.empty()){
		if(d[S.top()]==0) d[S.top()]=++time;
		found=false;
		for(i=0;i<n;i++){
		    if(d[i]==0 && M[S.top()][i]==1){
			found=true;
			break;
		    }
		}
		if(found) S.push(i);
		else {
		    f[S.top()]=++time;
		    S.pop();
		}
	    }
	}

   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>

#define MAX 101

using namespace std;

int visited[MAX],d[MAX],f[MAX];
int tt=0;
vector<int> G[MAX];

void dfs(int u){
  d[u]=++tt;
  for(int i=0;i<G[u].size();i++){
    if(visited[G[u][i]]==0) dfs(G[u][i]);
  }
  visited[u]=1;
  f[u]=++tt;
}

int main(){
  int n; cin >> n;
  for(int i=1;i<=n;i++) visited[i]=0;
  for(int i=0;i<n;i++){
    int u,k; cin >> u >> k;
    for(int i=0;i<k;i++){
      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;
  }
}