제출 #329286

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
329286		chenwz	카니발 티켓 (IOI20_tickets)	C++14	100 / 100	1113 ms	67656 KiB

tickets

#include "tickets.h"
#include <vector>
#include <algorithm>
#include <queue>
#include <cassert>
using namespace std;
typedef long long LL;
typedef vector<int> IVec;
typedef pair<LL, LL> pii;

long long find_maximum(int k, vector<IVec> d) {
  int N = d.size(), M = d[0].size(); // N color ×M tickets
  vector<IVec> o(N); // o.resize(N);
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < M; j++) o[i].push_back(j); // o[N][i]:index of ticket which is ith min from left
    sort(o[i].begin(), o[i].end(), [&](int a, int b) { return d[i][a] < d[i][b]; });
  }
  auto dval = [&](int c, int i) { return d[c][o[c][i]]; }; // num of ticket of color c which is ith form left
  LL cost = 0;
  IVec Plus(N, 0); // Plus[c] => How many '+'s the color c will send
  priority_queue<pii> gain; // gain: (change to cost by turning a - into a +, color index)
  for (int c = 0; c < N; c++) {
    for (int j = 0; j < k; j++) cost -= dval(c, j); // First incur cost of all L_c
    assert(Plus[c] == 0);
    gain.push(make_pair(dval(c, M - 1 - Plus[c]) + dval(c, k - 1 - Plus[c]), c)); // Queue a possible - to +
  }

  for (int i = 0; i < N * k / 2; i++) { // Take ck/2 +s
    pii it = gain.top(); gain.pop();
    cost += it.first;
    int c = it.second, &pc = Plus[c]; // If the color hasnt reached k +s, queue another possible +
    if (++pc < k) gain.push(pii(dval(c, M - 1 - pc) + dval(c, k - 1 - pc), c));
  }
  while (!gain.empty()) gain.pop();

  for (int c = 0; c < N; c++) gain.push(pii(Plus[c], c)); // gain: (+s remaining, color index)
  IVec minus(N, 0); // minus[color] => How many -s the color has sent so far
  vector<IVec> answer(N, IVec(M, -1));
  IVec take(N, 0); // take[c] => Does this c send a + in this rounds
  for (int i = 0; i < k; i++) { // Simulate k days of tickets
    for (int c = 0; c < N / 2; c ++) take[gain.top().second] = 1, gain.pop(); // Pick N/2 colors with the most +s left
    for (int c = 0; c < N; c++) { // Check if each color sent a - or +, and change answer accordingly
      int &p = Plus[c], &m = minus[c]; // color c sent a + this round, send the smallest +, Queue the color back
      if (take[c]) answer[c][o[c][M - p]] = i, gain.push(pii(--p, c));
      else answer[c][o[c][m++]] = i; // color c sent a - this round, send the smallest -
      take[c] = 0;
    }
  }

  allocate_tickets(answer);
  return cost;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 14 / 14
• Subtask 4: 14 / 14
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23
• Subtask 7: 10 / 10