Submission #684335

#	Time	Username	Problem	Language	Result	Execution time	Memory
684335		speedyArda	Rice Hub (IOI11_ricehub)	C++14	0 / 100	26 ms	2880 KiB

ricehub

#include "ricehub.h"
#include "bits/stdc++.h"

using namespace std;
using ll = long long;
int besthub(int R, int L, int X[], long long B)
{
  
  
  vector< pair<ll, ll> > road;
  for(int i = 0; i < R; i++)
  {
      int idx = i + 1, cnt = 1;
      while(idx < R && X[idx] == X[i])
      {
        cnt++;
        idx++;
      }
      idx--;
      road.push_back({X[i], cnt});
      i = idx;
  }
  int N = road.size();

  int left = 1, right = R;
  int ans = 0;
  while(left <= right)
  {
    int m = (left + right) / 2; // We are controlling whether we can get m rices. We use binary search because rice count is monotonic. For example, we can get 6 rices, if we can get 7 rices.
    //int mid = 1;
    bool valid = false;
    ll price = 1e18, tempprice = 0;
    int rice_cnt = 0;
    ll left_cnt = 0, right_cnt = 0;
  
    int endidx = -1, mid = -1;
    for(int beginidx = 0; beginidx < N; beginidx++)
    {
      ll curprice = 1e18;
      while(endidx < N && rice_cnt < m)
      {
        endidx++;
        rice_cnt += road[endidx].second;
        right_cnt += road[endidx].second;
        int prev = 0;
        if(mid != -1)
          prev = road[mid].first;
        tempprice += road[endidx].second * (road[endidx].first - prev);
        //endidx++;
      }
      //endidx--;
      
      int mini = 0;
      price = min(price, tempprice);
      curprice = min(tempprice, curprice);
      if(curprice == tempprice)
        mini = mid;
      while(left_cnt < right_cnt && mid < endidx - 1)
      {
          mid++;
          if(mid == 0) {
            tempprice -= right_cnt * (road[mid].first);
            //tempprice += left_cnt * road[mid].first;
          }
          else {
            tempprice -= right_cnt * (road[mid].first - road[mid - 1].first);
            tempprice += left_cnt * (road[mid].first - road[mid - 1].first);
          }
          
          right_cnt -= road[mid].second;
          left_cnt += road[mid].second;
          price = min(price, tempprice);
          curprice = min(tempprice, curprice);
          if(curprice == tempprice)
            mini = mid;
      }

      mid = mini;
      

      if(rice_cnt >= m && price <= B) {
        ans = max(ans, rice_cnt);
        valid = true;
      }

      rice_cnt -= road[beginidx].second;
      left_cnt -= road[beginidx].second;
      tempprice -= (road[mid].first - road[beginidx].first) * road[beginidx].second;
    }


    if(valid)
      left = m + 1;
    else
      right = m - 1;

  }
  return ans;
}



 

• Subtask 1: 0 / 17
• Subtask 2: 0 / 25
• Subtask 3: 0 / 26
• Subtask 4: 0 / 32