Submission #659612

#	Time	Username	Problem	Language	Result	Execution time	Memory
659612		peijar	Catfish Farm (IOI22_fish)	C++17	100 / 100	329 ms	55420 KiB

fish

#include "fish.h"
#include <bits/stdc++.h>
#define int long long
using namespace std;

const int INF = 1e18;

int max_weights(signed N, signed M, vector<signed> X, vector<signed> Y,
                vector<signed> W) {
  vector<vector<pair<int, int>>> onCol(N);
  vector<vector<int>> prefSum(N);
  for (int i = 0; i < M; ++i)
    onCol[X[i]].emplace_back(Y[i] + 1, W[i]);
  for (int i = 0; i < N; ++i) {
    sort(onCol[i].begin(), onCol[i].end());
    prefSum[i].resize(onCol[i].size() + 1);
    for (int j = 0; j < (int)onCol[i].size(); ++j)
      prefSum[i][j + 1] = prefSum[i][j] + onCol[i][j].second;
  }

  vector<vector<int>> interesting(N);
  for (int i = 0; i < N; ++i) {
    interesting[i].push_back(0);
    for (auto [y, w] : onCol[i])
      interesting[i].push_back(y);
    if (i)
      for (auto [y, w] : onCol[i - 1])
        interesting[i].push_back(y);
    if (i + 1 < N)
      for (auto [y, w] : onCol[i + 1])
        interesting[i].push_back(y);
    interesting[i].push_back(N);
    sort(interesting[i].begin(), interesting[i].end());
    interesting[i].resize(unique(interesting[i].begin(), interesting[i].end()) -
                          interesting[i].begin());
  }
  array<vector<pair<int, int>>, 2> oldDp, suffixMax;
  for (int i = 0; i < 2; ++i) {
    for (int x : interesting[0]) {
      oldDp[i].emplace_back(x, 0);
      suffixMax[i].emplace_back(x, 0);
    }
  }

  auto eval = [&](int side, int h) {
    auto it = upper_bound(oldDp[side].begin(), oldDp[side].end(), pair(h, INF));
    assert(it != oldDp[side].begin());
    --it;
    assert(it->first == h);
    return it->second;
  };

  auto getSum = [&](int i, int h1, int h2) -> int {
    if (h1 > h2)
      return 0;
    int lo = upper_bound(onCol[i].begin(), onCol[i].end(), pair(h1, INF)) -
             onCol[i].begin();
    int up = upper_bound(onCol[i].begin(), onCol[i].end(), pair(h2, INF)) -
             onCol[i].begin();
    return prefSum[i][up] - prefSum[i][lo];
  };

  int sol = 0;
  for (int i = 1; i < N; ++i) {
    int nbInteressants = interesting[i].size();
    vector<pair<int, int>> dp0, dp1;
    int curOld = 0;
    int cntBefore = interesting[i - 1].size();
    vector<int> prevI(cntBefore);
    vector<int> prevJ(cntBefore);
    int curPos = 0;
    int curSum = 0;
    for (int jHauteur = 0; jHauteur < cntBefore; ++jHauteur) {
      int oldH = interesting[i - 1][jHauteur];
      prevI[jHauteur] = oldDp[1][jHauteur].second;
      while (curPos < (int)onCol[i].size() and onCol[i][curPos].first <= oldH)
        curSum += onCol[i][curPos++].second;
      assert(curSum == getSum(i, 0, oldH));
      prevI[jHauteur] += curSum;
    }
    for (int j = cntBefore - 2; j >= 0; --j)
      prevI[j] = max(prevI[j], prevI[j + 1]);

    curPos = 0, curSum = 0;
    for (int jHauteur = 0; jHauteur < cntBefore; ++jHauteur) {
      int oldH = interesting[i - 1][jHauteur];
      while (curPos < (int)onCol[i - 1].size() and
             onCol[i - 1][curPos].first <= oldH)
        curSum += onCol[i - 1][curPos++].second;
      prevJ[jHauteur] = oldDp[0][jHauteur].second - curSum;
    }
    for (int jHauteur = 1; jHauteur < cntBefore; ++jHauteur)
      prevJ[jHauteur] = max(prevJ[jHauteur - 1], prevJ[jHauteur]);

    int curOld2 = 0;
    for (int iHauteur = 0; iHauteur < nbInteressants; ++iHauteur) {
      int h = interesting[i][iHauteur];
      // 1
      int v1 = 0;
      int v0 = 0;
      while (curOld < cntBefore and interesting[i - 1][curOld] <= h)
        ++curOld;
      assert(curOld);
      v0 = suffixMax[1][curOld - 1].second;
      if (curOld < cntBefore)
        v1 = max(v1, prevI[curOld] - getSum(i, 0, h));
      while (curOld2 < cntBefore and interesting[i - 1][curOld2] < h)
        ++curOld2;
      if (curOld2)
        v0 = max(v0, getSum(i - 1, 0, h) + prevJ[curOld2]);
      /*for (int jHauteur = 0; jHauteur < cntBefore; ++jHauteur) {
        int oldH = interesting[i - 1][jHauteur];
        if (oldH < h)
          v0 = max(v0, getSum(i - 1, oldH, h) + eval(0, oldH));
      }*/
      v1 = max(v1, v0);
      sol = max(sol, v1);
      dp0.emplace_back(h, v0);
      dp1.emplace_back(h, v1);
      // cout << i << ' ' << h << ' ' << v0 << ' ' << v1 << endl;
    }
    oldDp[0] = move(dp0);
    oldDp[1] = move(dp1);
    suffixMax[0] = oldDp[0];
    suffixMax[1] = oldDp[1];
    for (int h = nbInteressants - 2; h >= 0; --h)
      for (int side = 0; side < 2; ++side)
        suffixMax[side][h].second =
            max(suffixMax[side][h].second, suffixMax[side][h + 1].second);
  }
  return sol;
}

Compilation message (stderr)

fish.cpp: In function 'long long int max_weights(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
fish.cpp:45:8: warning: variable 'eval' set but not used [-Wunused-but-set-variable]
   45 |   auto eval = [&](int side, int h) {
      |        ^~~~

• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 9 / 9
• Subtask 4: 14 / 14
• Subtask 5: 21 / 21
• Subtask 6: 17 / 17
• Subtask 7: 14 / 14
• Subtask 8: 16 / 16