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<vector>
#include<algorithm>
#include<cctype>
#include<utility>
#include<string>
#include<cmath>
#include<cstring>
#include<queue>
#include<map>
#include<set>
#include<climits>

#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, m, n) for(int i = m;i < n;i++)
#define FORR(i, m, n) for(int i = m;i >= n;i--)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define llong long long
#define pb(a) push_back(a)

using namespace std;

typedef long long int ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;


template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
	return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}
template<typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type
fill_v(T& t, const V& v) { t = v; }
template<typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type
fill_v(T& t, const V& v) {
	for (auto& e : t) fill_v(e, v);
}


#define ARRAY_MAX 100005
const int INF = INT32_MAX / 3;
const ll MOD = 1e9 + 7;

int dx[4] = { 1,0,0,-1 };
int dy[4] = { 0,1,-1,0 };


/******************************************************************************************/


vector<int> G[105];
int cnt = 1;
int d[105];
int f[105];
int check[105];

void dfs(int now) {

	
	d[now] = cnt;
	check[now] = 1;
	cnt++;

	for (auto itr : G[now]) {

		if (check[itr] == 1)continue;
		dfs(itr);
	}
	f[now] = cnt;
	cnt++;
}



int main() {

	int n;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		int v, k;
		cin >> v >> k;
		v--;
		for (int j = 0; j < k; j++)
		{
			int c;
			cin >> c;
			c--;
			G[v].push_back(c);
		}
	}
	for (int i = 0; i < n; i++)
	{
		if (check[i] == 1)continue;
		dfs(i);
	}

	

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


	return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <string>
#include <algorithm>
#include <utility>
#include <climits>
#include <cstring>
#include <cstdio>

using namespace std;
typedef long long int llg;

const int INF = 1000001000;
#define REP(var, count) for(int var=0; var<count; var++)

template <typename T>
using reverse_queue = std::priority_queue<T, std::vector<T>, std::greater<T> >;

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
	std::fill( (T*)array, (T*)(array+N), val );
}

vector<int> rin[105];
pair<int, int> res[105];

int bfs(int a, int time) {
	if ( res[a].first != -1 ) { return time; }
	time++;
	res[a].first = time;
	for ( int r : rin[a] ) {
		time = bfs(r, time);
	}
	time++;
	res[a].second = time;
	return time;
}

int main(void) {
	int N;
	cin >> N;
	
	for(int i=1; i<=N; i++) {
		res[i].first = -1;
		res[i].second = -1;
		
		int U, K;
		cin >> U >> K;
		REP(j, K) {
			int x;
			cin >> x;
			rin[U].push_back(x);
		}
	}
	
	bfs(1, 0);
	
	for(int i=1; i<=N; i++) {
		printf("%d %d %d\n", i, res[i].first, res[i].second);
	}
}

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, tt;
int M[N][N], color[N], d[N], f[N], nt[N]; 

int next(int u){
	for(int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		if(M[u][v] == 1) 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 {
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


void dfs() {
	for(int i = 0; i < n; i++) {
	     color[i] = WHITE;
	}	
	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 n, k , u, v;
	tt = 0;
	cin >> n;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}
	cin >> k >> u;
	u--;
	for(int i = 0; i < k; i++) {
	    cin >> v;
	    v--;
		M[u][v] = 1; 
	}
	dfs();
	return 0;
}

C++: #include <iostream>

using namespace std;

int Time=0,d[101],f[101],v[101][101];
void Init()
{
    int i;
    for(i=1;i<=100;i++)
        d[i]=0;
}
void dfs(int cur,int n)
{
    int i;
    Time += 1;
    d[cur]=Time;
    for(i=1;i<=n;i++)
    {
        if(v[cur][i]==1 && d[i]==0)
            dfs(i,n);
    }
    Time += 1;
    f[cur] = Time;
}
int Find(int n,int d[])
{
    int flag=0,i;
    for(i=1;i<=n;i++)
        if(d[i]==0)
        {
            flag=i;
            break;
        }
    return flag;
}
int main()
{
    int n,m,k,i,j,flag;
    cin >> n;
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
            v[i][j]=0;
    for(i=1;i<=n;i++)
    {
        cin >> i >> k;
        for(j=1;j<=k;j++)
        {
            cin >> m;
            v[i][m]=1;
        }
    }
    Init();
    dfs(1,n);
    while(1)
    {
        flag = Find(n,d);
        if(flag == 0)
            break;
        else    dfs(flag,n);
    }
    for(i=1;i<=n;i++)
    {
        cout << i << ' ' << d[i] << ' ' << f[i] << endl;
    }
    return 0;
}