Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveDfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: #include <iostream>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <algorithm>
#include <cmath>
#include <string>
using namespace std;
typedef long long lli;
typedef vector<lli> vll;
typedef vector<bool> vbl;
typedef vector<vector<lli> > mat;
typedef vector<vector<bool> > matb;
typedef vector<string> vst;
typedef pair<lli,lli> pll;
typedef pair<double,double> pdd;

lli n;
mat g;
vll d;
vll f;
vbl vis;

lli u,k,v;

lli dfs(lli x,lli t){
    d[x] = t;
    vis[x] = true;
    for(lli i = 0;i < g[x].size();i++){
        if(!vis[g[x][i]]) t = dfs(g[x][i],t+1);
    }
    return f[x] = t + 1;
}

int main(){
    cin >> n;
    g = mat(n+1);
    d = vll(n+1);
    f = vll(n+1);
    vis = vbl(n+1);
    for(lli i = 0;i < n;i++){
        cin >> u >> k;
        for(lli i = 0;i < k;i++){
            cin >> v;
            g[u].push_back(v);
        }
    }
    dfs(1,1);
    for(lli i = 1;i <= n;i++){
        cout << i << " " << d[i] << " " << f[i] << endl;
    }
    return 0;
}

C++: #include <iostream>
#define MAX 101

using namespace std;

bool flag[MAX][MAX];
int t[MAX][2];
int n;

void dfs(int num){
	static int cnt = 1;
	
	if(t[num][0] == 0)t[num][0] = cnt++;
	else return;
	for(int i=1;i<=n;++i){
		if(flag[num][i] == true){
			dfs(i);
		}
	}
	t[num][1] = cnt++;
}

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

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

using namespace std;


struct Edge{ //??°????????????
public:
    int src, dst;
    int weight;
    Edge(int a,int b):src(a),dst(b),weight(1){} //?????????????????????
    void setWeight(double x){
        weight = x;
    }
};
typedef vector<Edge> Edges; //???????????£??\?????????
typedef vector<Edges> Graph; //??°???????????£??\???????????¨???

typedef vector<int> Array; //??´??°?????????
typedef vector<Array> Matrix; //??´??°???????????£??\?????????

const int N = 100;
const int White = 0, Gray = 1, Black =2;

int n;
int tt = 0;
Matrix M(N,Array(N,0));
vector<int> d(N,0), f(N,0);
vector<int> color(N,0);


vector<int> nt(N,0);//???????????????????????????????????§?????????????¨???¶??????

int next(int u){ //???u?????\?¶??????????????????????????????????
    if (nt[u]!= n) {
        for(int i = nt[u];i<n;i++){
            if(M[u][i]){
                nt[u] = i+1;
                return i;
            }
        }
        return -1;
    } else {
        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 v = S.top();
        int w = next(v);
        if (w != -1) {
            if (color[w]==White) {
                color[w] = Gray;
                d[w] = ++tt;
                S.push(w);
            }
        } else {
            S.pop();
            color[v] = Black;
            f[v] = ++tt;
        }
    }
    
}

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


int main(){
    
    int k,v,w;
    
    cin >> n; //??°????????????????????\???
    
    for (int i=0; i<n; i++) { //??????????¬???°?????????????????\??? ???????????\??????????????£??\??????????????£??\?????????????´?
        cin >> w >> k;
        for (int j=0; j<k; j++) {
            cin >> v;
            M[w-1][v-1] = 1; //?????????
        }
    }
    
    dfs();
    
    return 0;
}

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

// 総数を1000000007で割った余り
const long long mod = 1e9 + 7;

using ll  = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define ull unsigned long long
#define ld long double
#define vi vector<int>
#define vll vector<ll>
#define vc vector<char>
#define vs vector<string>
#define vpii vector<pii>
#define vpll vector<pll>

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; i++)
#define rep1(i, n) for (int i = 1, i##_len = (n); i <= i##_len; i++)
#define repr(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define rep1r(i, n) for (int i = ((int)(n)); i >= 1; i--)

#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

#define SORT(v, n) sort(v, v + n);
// #define SORT(v, n) stable_sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RSORT(x) sort(rall(x));
#define pb push_back
#define mp make_pair

#define INF (1e9)
#define PI (acos(-1))
#define EPS (1e-7)

ull gcd(ull a, ull b) { return b ? gcd(b, a % b) : a; }
ull lcm(ull a, ull b) { return a / gcd(a, b) * b; }

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

int n, m[N][N];
int color[N], d[N], f[N], tt;

// 再帰による深さ優先探索
void dfs_visit(int u) {
    color[u] = gray;
    d[u]     = ++tt;  //最初の訪問
    rep(v, n) {
        if (m[u][v] == 0) continue;
        if (color[v] == white) {
            dfs_visit(v);
        }
    }
    color[u] = black;
    f[u]     = ++tt;  // 訪問の完了
}

void dfs() {
    //初期化
    rep(u, n) color[u] = white;
    tt                 = 0;
    rep(u, n) {
        // 未訪問のuを始点として深さ優先探索
        if (color[u] == white) dfs_visit(u);
    }
    rep(u, n) { cout << u + 1 << " " << d[u] << " " << f[u] << endl; }
}

// 再帰による深さ優先探索
int main() {
    int u, v, k;
    cin >> n;
    rep(i, n) rep(j, n) m[i][j] = 0;

    rep(i, n) {
        cin >> u >> k;
        u--;
        rep(j, k) {
            cin >> v;
            v--;
            m[u][v] = 1;
        }
    }
    dfs();

    return 0;
}