Submission #908651

#	Time	Username	Problem	Language	Result	Execution time	Memory
908651		vjudge1	Catfish Farm (IOI22_fish)	C++17	0 / 100	89 ms	22344 KiB

fish

#include <bits/stdc++.h>
#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")

#include<bits/stdc++.h>
#include<math.h>
using namespace std;

typedef long long int ll;
typedef long double ld;
typedef pair<ll, ll> pl;
typedef vector<ll> vl;
#define FD(i, r, l) for(ll i = r; i > (l); --i)

#define K first
#define V second
#define G(x) ll x; cin >> x;
#define GD(x) ld x; cin >> x;
#define GS(s) string s; cin >> s;
#define EX(x) { cout << x << '\n'; exit(0); }
#define A(a) (a).begin(), (a).end()
#define F(i, l, r) for (ll i = l; i < (r); ++i)

enum {
    UP = 0,
    DOWN = 1
};

ll max_weights(int N, int M, std::vector<int> X, std::vector<int> Y,
                      std::vector<int> W) {
  vector<vector<pair<int, int>>> fishes(N);

  F(i, 0, M) fishes[X[i]].push_back(make_pair(Y[i], i));

  ll two_columns_back = 0;
  
  vector<pl> up, down; // stores [ypos, dpvalue] of prev state

  vector<vl> dp(M, vl(2, -1e18)); // dp[fish index][type]

  F(x, 0, N) {
    sort(fishes[x].begin(), fishes[x].end());

    if (x > 0) { // w/o this check, we allow placing piers to index -1 which is no bueno
      ll max_down = 0;
      FD(j, ll(fishes[x].size()) - 1, -1) {
        auto [y, i] = fishes[x][j];
        while (down.size() > 0 && down.back().K > y) {
            max_down = max(max_down, down.back().V);
            down.pop_back();
        }

        auto &ret = dp[i][DOWN];
        ret = max(two_columns_back, max_down);

        // taking cummulative max 
        if (j + 1 < fishes[x].size()) {
          ret = max(ret, dp[fishes[x][j + 1].V][DOWN]);
        }
        ret += W[i];
      }
    }

    ll max_up = 0;
    for (int j = 0; j < fishes[x].size(); ++j) {
        auto [y, i] = fishes[x][j];
        while (up.size() > 0 && up.back().K < y) {
            max_up = max(max_up, up.back().V);
            up.pop_back();
        }

        ll &ret = dp[i][UP];
        ret = max(two_columns_back, max_up);
        if (j > 0) {
            ret = max(ret, dp[fishes[x][j - 1].V][UP] + W[i]);
        }
        ret += W[i];
    }

    // 
    if (x >= 1) for (auto [y, i] : fishes[x - 1]) {
        two_columns_back = max({two_columns_back, dp[i][UP], dp[i][DOWN]});
    }

    down.clear();
    for (auto [y, i]: fishes[x]) down.emplace_back(y, dp[i][DOWN]);
    up.clear();
    for (auto [y, i]: fishes[x]) up.emplace_back(y, dp[i][UP]);
    reverse(A(up));
  }

  ll answer = 0;
  F(i, 0, M) {
    answer = max(answer, dp[i][DOWN]);
    if (X[i] + 1 < N) answer = max(answer, dp[i][UP]);
  }

  return answer;
}

Compilation message (stderr)

fish.cpp: In function 'll max_weights(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
fish.cpp:58:19: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |         if (j + 1 < fishes[x].size()) {
      |             ~~~~~~^~~~~~~~~~~~~~~~~~
fish.cpp:66:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |     for (int j = 0; j < fishes[x].size(); ++j) {
      |                     ~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 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