Submission #1130968

#	Time	Username	Problem	Language	Result	Execution time	Memory
1130968		belgianbot	Catfish Farm (IOI22_fish)	C++20	3 / 100	187 ms	58112 KiB

fish

#include "fish.h"

#include <bits/stdc++.h>

using namespace std;

struct fish {
  int x, y, w;
};
int M, N;
vector<fish> f;
vector<int> idxAct;
vector<vector<long long>> prefAct;
vector<long long> memo;

long long prefixAct(int n, int l, int r) {
  if (r < l) return 0;
  if (l <= 0) return prefAct[n][r];
  return prefAct[n][r] - prefAct[n][l-1];
}
bool comp2 (const fish &a, const fish &b) {
  if (a.x < b.x) return true;
  if (a.x == b.x && a.y < b.y) return true;
  if (a.x == b.x && a.y == b.y && a.w < b.w) return true;
  return false;
}
long long dp(int i) {
  if (i >= M) return 0;

  if (memo[i] != -1) return memo[i];

  long long notake = dp(i + 1);
  
  int index = lower_bound(f.begin(), f.end(), fish({f[i].x + 1, -1, -1}), comp2) - f.begin();

  long long takeLeft = dp(index) + prefixAct(f[i].x, 0, idxAct[i]);
  long long takeRight = dp(index) + prefixAct(f[i].x, 0, idxAct[i]);
  
  int index2 = lower_bound(f.begin(), f.end(), fish({f[i].x + 1, f[i].y + 1, -1}), comp2) - f.begin() - 1;
  if (f[index2].x == f[i].x+1) takeRight -= prefixAct(f[i].x+1, 0, idxAct[index2]);

  int index3 = lower_bound(f.begin(), f.end(), fish({f[i].x - 1, f[i].y + 1, -1}), comp2) - f.begin() - 1;
  if (f[index3].x == f[i].x-1) takeLeft -= prefixAct(f[i].x - 1, 0, idxAct[index3]);
  
  if (!f[i].x) takeLeft = 0;
  if (f[i]. x >= N-1) takeRight = 0;
  return memo[i] = max(notake, max(takeLeft, takeRight));
}
long long max_weights(int NN, int MM, vector<int> X, vector<int> Y,vector<int> W) {
  ios::sync_with_stdio(false);
  M = MM, N = NN;
  f.resize(M);
  for (int i = 0; i < M; i++) f[i] = fish({X[i], Y[i], W[i]});

  sort(f.begin(), f.end(), comp2);

  prefAct.resize(N); idxAct.resize(M);
  for (int i = 0; i < M; i++) {
    idxAct[i] = (int)(prefAct[f[i].x].size());
    prefAct[f[i].x].push_back(f[i].w);
  }
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < int(prefAct[i].size()); j++) {
      if (j) prefAct[i][j] += prefAct[i][j-1];
    }
  }
  memo.resize(M,-1);

  return dp(0);
}

• Subtask 1: 3 / 3
• Subtask 2: 0 / 6
• Subtask 3: 0 / 9
• Subtask 4: 0 / 14
• Subtask 5: 0 / 21
• Subtask 6: 0 / 17
• Subtask 7: 0 / 14
• Subtask 8: 0 / 16