Submission #1076938

#	Time	Username	Problem	Language	Result	Execution time	Memory
1076938		bleahbleah	Tortoise (CEOI21_tortoise)	C++17	0 / 100	1 ms	600 KiB

tortoise

#include <bits/stdc++.h>
#define all(x) (x).begin(),(x).end()
using namespace std;
 
//#ifndef DLOCAL
//   #define cin fin
//   #define cout fout
//   ifstream cin(".in");
//   ofstream cout(".out");
//#endif
 
using ll = long long;
using ld = long double;
 
#define int ll
#define sz(x) ((int)(x).size())
 
using pii = pair<int,int>;
using tii = tuple<int,int,int>;
 
const int nmax = 5e5 + 5;
 
int Ld[nmax], Rd[nmax];
int v[nmax];
 
bool possible(multiset<int> s) {
   int last = -1, timer = 0;
   for(auto x : s) {
      if(last == -1) {
         timer += x - 1;
      }
      else {
         if(Ld[last] != Ld[x] || Rd[last] != Rd[x])
            timer += x - last;
         else timer += min(last - Ld[last] + x - Ld[last], Rd[last] - last + Rd[last] - x);
      }
      if(timer > 2 * (x - 1)) { return 0; }
      last = x;
      //cerr << timer << '\n';
   }
   //cerr << '\n';
   //for(auto x: s) cerr << x << ' '; cerr << '\n';
   //cerr << "ok\n";
   return 1;
}
 
signed main() {
   cin.tie(0) -> sync_with_stdio(0);
   int n;
   cin >> n;
   
   ll cost = 0;
   for(int i = 1; i <= n; i++)
      cin >> v[i], cost += (v[i] != -1? v[i] : 0);
   for(int lst = -1e9 - 5, i = 1; i <= n; i++) {
      if(v[i] == -1) lst = i;
      else Ld[i] = lst;
   }
   for(int lst = 1e9 + 5, i = n; i > 0; i--) {
      if(v[i] == -1) lst = i;
      else Rd[i] = lst;
   }
   
   vector<pii> idxs;
   multiset<int> sofar;
   
   for(int i = 1; i <= n; i++) {
      if(v[i] == -1) continue;
      idxs.emplace_back(min(Rd[i] - i, i - Ld[i]), i);
   }
   sort(all(idxs));
   
   
   mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
   
   shuffle(all(idxs) ,rng);
   for(auto [DD, x] : idxs) {
      while(v[x] > 0) {
         sofar.emplace(x);
         if(possible(sofar)) v[x]--;
         else {
            sofar.erase(sofar.find(x));
            break;
         }
      }
   }
   
   cost = 0;
   for(int i = 1; i <= n; i++)
      cost += (v[i] != -1? v[i] : 0);
   
   cout << cost << '\n';
 
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 25
• Subtask 5: 0 / 27