Submission #1025432

#	Time	Username	Problem	Language	Result	Execution time	Memory
1025432		joelgun14	Hacker (BOI15_hac)	C++17	100 / 100	259 ms	26256 KiB

hac

// header file
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
// pragma
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
// macros
#define endl "\n"
#define ll long long
#define mp make_pair
#define ins insert
#define lb lower_bound
#define pb push_back
#define ub upper_bound
#define lll __int128
#define fi first
#define se second
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
int main() {
  ios_base::sync_with_stdio(0); cin.tie(NULL);
  int n;
  cin >> n;
  ll a[n + 1], pref[2 * n + 1];
  for(int i = 1; i <= n; ++i)
    cin >> a[i];
  pref[0] = 0;
  for(int i = 1; i <= 2 * n; ++i)
    pref[i] = pref[i - 1] + (i > n ? a[i - n] : a[i]);
  multiset<ll> s;
  for(int i = 1; i + n / 2 < n + 1; ++i) {
    // cerr << "INS " << i << " " << pref[i + n / 2] - pref[i] << endl;
    s.insert(pref[i + n / 2] - pref[i]);
  }
  ll res = 0;
  for(int i = 1; i <= n; ++i) {
    // cerr << "DEB " << i << " " << *--s.end() << endl;
    res = max(res, pref[n] - *--s.end());
    s.erase(s.find(pref[i + n / 2] - pref[i]));
    s.insert(pref[n + i] - pref[i + n - n / 2]);
  }
  cout << res << endl;
  return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 40 / 40