Submission #1169346

#	Time	Username	Problem	Language	Result	Execution time	Memory
1169346		LucaLucaM	Boxes with souvenirs (IOI15_boxes)	C++20	100 / 100	1708 ms	243112 KiB

boxes

#include "boxes.h"
#include <vector>
#include <algorithm>
#include <iostream>
#include <cassert>

using ll = long long;
#define debug(x) #x << " = " << x << '\n'

ll delivery(int n, int k, int L, int p[]) {
  std::vector<std::pair<int, int>> v(n);
  for (int i = 0; i < n; i++) {
    v[i].first = std::min(p[i], L - p[i]);
    v[i].second = p[i];
  } 

  std::sort(v.begin(), v.end());
  std::reverse(v.begin(), v.end());

  std::vector<int> st, dr;
  for (int i = 0; i < n; i++) {
    if (v[i].first == v[i].second) {
      st.push_back(v[i].first);
    } else {
      dr.push_back(v[i].first);
    }
  }

  std::sort(st.begin(), st.end());
  std::sort(dr.begin(), dr.end());

  ll answer = 1e18;

  std::vector<ll> sumst((int) st.size(), 0);
  std::vector<ll> sumdr((int) dr.size(), 0);
  
  for (int i = 0; i < (int) st.size(); i++) {
    sumst[i] = st[i];
    if (i >= k) {
      sumst[i] += sumst[i - k];
    }
  }
  for (int i = 0; i < (int) dr.size(); i++) {
    sumdr[i] = dr[i];
    if (i >= k) {
      sumdr[i] += sumdr[i - k];
    }
  }

  std::vector<ll> best(k, 1e18);

  for (int cater = 0; cater <= (int) dr.size(); cater++) {
    ll you = 0;
    if (cater % k == 0) {
      if (cater < (int) dr.size()) {
        you += (ll) 2 * sumdr[(int) dr.size() - cater - 1];
      }
      you += (ll) L * (cater / k);
    } else {
      if (cater < (int) dr.size()) {
        you += (ll) 2 * sumdr[(int) dr.size() - cater - 1];
      }
      you += (ll) L * (1 + cater / k);
    }
    best[cater % k] = std::min(best[cater % k], you); 
  }

  for (int catel = 0; catel <= (int) st.size(); catel++) { // dintre turele full, cate sterg din st?
    // catel + cater = 0 (mod k) <=> cater = k - catel (mod k)
    ll me = 0;
    if (catel < (int) st.size()) {
      me += (ll) 2 * sumst[(int) st.size() - catel - 1];
    }
    me += (ll) L * (catel / k);
    int you = catel % k == 0? 0 : k - catel % k;
    answer = std::min(answer, me + best[you]);
  }
  
  return answer;
}

// daca da 70 si nu 100 e destul de troll

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 30 / 30