Why I am getting TLE at CSES problem "Book Shop" of dynamic programming - c++17

Question

TLE
I am getting the same error in case of coin combination 2
link to the problem
Failed tc
//*******************************************
// Code by:
// * *
// * * * *
// ***** *****
// * * * *
// * *arushi * * garwal
//*******************************************
#include <bits/stdc++.h>
using namespace std;
#define fastio() \
ios_base::sync_with_stdio(false); \
cin.tie(NULL);
#define yes cout << "YES\n"
#define no cout << "NO\n"
#define MOD 1000000007
#define endl "\n"
#define MOD1 998244353
#define INF 1e18
#define nline "\n"
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define set_bits __builtin_popcountll
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define for0 for (i = 0; i < n; i++)
#define for1 for (i = 1; i <= n; i++)
#define forr for (i = n - 1; i >= 0; i--)
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
// typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update > pbds; // find_by_order, order_of_key
#ifndef ONLINE_JUDGE
#define debug(x) \
cerr << #x << " "; \
_print(x); \
cerr << endl;
#else
#define debug(x)
#endif
void _print(ll t)
{
cerr << t;
}
void _print(int t) { cerr << t; }
void _print(string t) { cerr << t; }
void _print(char t) { cerr << t; }
void _print(lld t) { cerr << t; }
void _print(double t) { cerr << t; }
void _print(ull t) { cerr << t; }
template <class T, class V>
void _print(pair<T, V> p);
template <class T>
void _print(vector<T> v);
template <class T>
void _print(set<T> v);
template <class T, class V>
void _print(map<T, V> v);
template <class T>
void _print(multiset<T> v);
template <class T, class V>
void _print(pair<T, V> p)
{
cerr << "{";
_print(p.ff);
cerr << ",";
_print(p.ss);
cerr << "}";
}
template <class T>
void _print(vector<T> v)
{
cerr << "[ ";
for (T i : v)
{
_print(i);
cerr << " ";
}
cerr << "]";
}
template <class T>
void _print(set<T> v)
{
cerr << "[ ";
for (T i : v)
{
_print(i);
cerr << " ";
}
cerr << "]";
}
template <class T>
void _print(multiset<T> v)
{
cerr << "[ ";
for (T i : v)
{
_print(i);
cerr << " ";
}
cerr << "]";
}
template <class T, class V>
void _print(map<T, V> v)
{
cerr << "[ ";
for (auto i : v)
{
_print(i);
cerr << " ";
}
cerr << "]";
}
// EVERY SINGLE QUES TAKES YOU TOWARDS YOUR GOAL :)
// ********************************************************
int i, t, j, sum, n, ans, k;
const int M = 1e9 + 7;
const int N = 1e5;
int dp[1001][N + 1];
ll binExp(ll a, ll b)
{
ll result = 1;
while (b > 0)
{
if (b & 1)
result = (result * a) % M;
a = (a * a) % M;
b >>= 1;
}
return result;
}
int fun(int i, int price[], int pages[], int cost)
{
if (i < 0)
return 0;
if (cost == 0)
return 0;
if (dp[i][cost] != -1)
return dp[i][cost];
int ans = fun(i - 1, price, pages, cost);
if (cost >= price[i])
ans = max(ans, fun(i - 1, price, pages, cost - price[i]) + pages[i]);
return dp[i][cost] = ans;
}
void hacked()
{
// cin>>n;
// string s;
// cin>>s;
cin >> n >> sum;
int price[n];
int pages[n];
memset(dp, -1, sizeof(dp));
for (i = 0; i < n; i++)
{
cin >> price[i];
}
for (i = 0; i < n; i++)
{
cin >> pages[i];
}
cout << fun(n - 1, price, pages, sum) << endl;
}
int main()
{
#ifndef ONLINE_JUDGE
freopen("Error.txt", "w", stderr);
#endif
ios_base::sync_with_stdio(false);
cin.tie(NULL);
hacked();
return 0;
}`
I tried using int instead of long long but still getting tle.
You are in a book shop which sells n different books. You know the
price and number of pages of each book.
You have decided that the total price of your purchases will be at
most x. What is the maximum number of pages you can buy? You can buy
each book at most once.

Answer 1

Maybe because of the auxiliary space used up by top-down approach - the recursive stack- bottom-up works tho.
UPD: I just read this CF BLOG, people mention about the strict constraints of CSES, so it's better to solve using bottom-up.