Problem p02709 (C++)

Buggy submission (status: Time Limit Exceeded):
#include "bits/stdc++.h"
using namespace std;
#define sim template <class c
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \
  sim > typename enable_if<sizeof dud<c>(0) x 1, debug &>::type operator<<(    \
            c i) {
sim > struct rge {
  c b, e;
};
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) cerr << boolalpha << i;
  ris;
} eni(==) ris << range(begin(i), end(i));
}
sim, class b dor(pair<b, c> d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
  sim dor(const c &) { ris; }
#endif
}
;
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define cool                                                                   \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define int long long int
#define pb push_back
#define fe first
#define lb lower_bound
#define ub upper_bound
#define pii pair<pair<int, int>, pair<int, int>>
#define se second
#define endl "\n"
#define pi pair<int, int>
#define mi map<int, int>
#define mii map<pi, int>
#define vi vector<int>
#define vvi vector<vi>
#define bs binary_search
#define rep(i, a, b) for (int i = a; i < b; i++)
#define rep1(i, a, b) for (int i = a; i <= b; i++)
#define all(c) (c).begin(), (c).end()
#define sz(x) (int)x.size()
#define PI 3.14159265358979323846

const int N = 2e3 + 5;

int mod = 1e9 + 7;
int dx[4] = {0, 0, +1, -1};
int dy[4] = {+1, -1, 0, 0};

int po(int a, int b) {
  a %= mod;
  int res = 1;
  while (b > 0) {
    if (b & 1)
      res = (res * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return res;
}

int dp[N][N];
vector<pi> a;

int go(int pos, int l, int r) {
  if (pos == sz(a))
    return 0;
  if (dp[pos][l] != -1)
    return dp[pos][l];
  return max(go(pos + 1, l + 1, r) + a[pos].fe * abs(a[pos].se - l),
             go(pos + 1, l, r - 1) + a[pos].fe * abs(a[pos].se - r));
}

void solve() {
  int n;
  cin >> n;

  rep(i, 0, n) {
    int x;
    cin >> x;
    a.pb({x, i});
  }

  sort(a.rbegin(), a.rend());
  memset(dp, -1, sizeof(dp));

  cout << go(0, 0, n - 1);
  cout << endl;
}

int32_t main() {
  cool;
  int t = 1;

  // cin>>t;
  while (t--)
    solve();

  return 0;
}


Fixed submission:
#include "bits/stdc++.h"
using namespace std;
#define sim template <class c
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \
  sim > typename enable_if<sizeof dud<c>(0) x 1, debug &>::type operator<<(    \
            c i) {
sim > struct rge {
  c b, e;
};
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) cerr << boolalpha << i;
  ris;
} eni(==) ris << range(begin(i), end(i));
}
sim, class b dor(pair<b, c> d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
  sim dor(const c &) { ris; }
#endif
}
;
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define cool                                                                   \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define int long long int
#define pb push_back
#define fe first
#define lb lower_bound
#define ub upper_bound
#define pii pair<pair<int, int>, pair<int, int>>
#define se second
#define endl "\n"
#define pi pair<int, int>
#define mi map<int, int>
#define mii map<pi, int>
#define vi vector<int>
#define vvi vector<vi>
#define bs binary_search
#define rep(i, a, b) for (int i = a; i < b; i++)
#define rep1(i, a, b) for (int i = a; i <= b; i++)
#define all(c) (c).begin(), (c).end()
#define sz(x) (int)x.size()
#define PI 3.14159265358979323846

const int N = 2e3 + 5;

int mod = 1e9 + 7;
int dx[4] = {0, 0, +1, -1};
int dy[4] = {+1, -1, 0, 0};

int po(int a, int b) {
  a %= mod;
  int res = 1;
  while (b > 0) {
    if (b & 1)
      res = (res * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return res;
}

int dp[N][N];
vector<pi> a;

int go(int pos, int l, int r) {
  if (pos == sz(a))
    return 0;
  int &ans = dp[pos][l];
  if (ans != -1)
    return ans;
  return ans = max(go(pos + 1, l + 1, r) + a[pos].fe * abs(a[pos].se - l),
                   go(pos + 1, l, r - 1) + a[pos].fe * abs(a[pos].se - r));
}

void solve() {
  int n;
  cin >> n;

  rep(i, 0, n) {
    int x;
    cin >> x;
    a.pb({x, i});
  }

  sort(a.rbegin(), a.rend());
  memset(dp, -1, sizeof(dp));

  cout << go(0, 0, n - 1);
  cout << endl;
}

int32_t main() {
  cool;
  int t = 1;

  // cin>>t;
  while (t--)
    solve();

  return 0;
}