Submission #954289

#	Time	Username	Problem	Language	Result	Execution time	Memory
954289		Trisanu_Das	Sequence (APIO23_sequence)	C++17	28 / 100	344 ms	43076 KiB

sequence

#include <bits/stdc++.h>
#include "sequence.h"
using namespace std;
 
int sequence(int n, vector<int> a){
  int ans = 0;
  if(n <= 2000){
    int occ[n + 1];
    for(int i = 0; i < n; i++){
      memset(occ, 0, sizeof(occ));
      multiset<int> l, r;
      for(int j = i; j < n; j++){
        occ[a[j]]++;
        if(r.empty() || a[j] <= *r.begin()) l.insert(a[j]);
        else r.insert(a[j]);
 
        if(l.size() > r.size() + 1){
          r.insert(*--l.end());
          l.erase(--l.end());
        }
        if(r.size() > l.size()){
          l.insert(*r.begin());
          r.erase(r.begin());
        }
        ans = max(ans, occ[*--l.end()]);
        if(l.size() == r.size()) ans = max(ans, occ[*r.begin()]);
      }
    }
    return ans;
  }
  map<int, int> asc, desc;
  bool flag = true;
  for(int i = 0; i < n; i++){
    if(flag) asc[a[i]]++;
    else desc[a[i]]++;
    if(i && a[i] <= a[i - 1]) flag = false;
  }
  for(auto p : asc){
    auto p2 = lower_bound(a.begin(), a.end(), p.first) - a.begin();
    if(p2 >= n / 2) ans = max(ans, p.second + desc[p.first]);
  }
  for(auto p : desc){
    auto p2 = upper_bound(a.begin(), a.end(), p.first) - a.begin();
    if(p2 >= n / 2) ans = max(ans, p.second + asc[p.first]);
  }
  return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 17 / 17
• Subtask 3: 0 / 7
• Subtask 4: 0 / 12
• Subtask 5: 0 / 13
• Subtask 6: 0 / 22
• Subtask 7: 0 / 18