Submission #1210424

#	Time	Username	Problem	Language	Result	Execution time	Memory
1210424		thangdz2k7	Catfish Farm (IOI22_fish)	C++20	100 / 100	125 ms	35564 KiB

fish

#include "fish.h"
#include <bits/stdc++.h>

using namespace std;

template <int D, typename T>
struct Vec : public vector<Vec<D - 1, T>> {
    static_assert(D >= 1, "Dimension must be positive");
    template <typename... Args>
    Vec(int n = 0, Args... args) : vector<Vec<D - 1, T>>(n, Vec<D - 1, T>(args...)) {}
};

template <typename T>
struct Vec<1, T> : public vector<T> {
    Vec(int n = 0, T val = T()) : std::vector<T>(n, val) {}
};

long long max_weights(int N, int M, vector <int> X, vector <int> Y, vector <int> W){
    vector <vector <pair <int, int>>> fishes(N);
    vector <int> siz(N);

    for (int i = 0; i < N; ++ i)
        fishes[i].emplace_back(N, 0);

    for (int i = 0; i < M; ++ i)
        fishes[X[i]].emplace_back(Y[i], W[i]);

    Vec <2, vector <long long>> dp(N, 2);

    for (int i = 0; i < N; ++ i){
        sort(fishes[i].begin(), fishes[i].end());
        siz[i] = fishes[i].size();

        for (int t : {0, 1})
            dp[i][t].resize(siz[i], 0);
    }

    auto maxl = [&](long long &a, long long b) -> void {
        a = max(a, b);
    };

    for (int i = 1; i < N; ++ i){
        long long val_up = 0;
        int ptr = 0;
        for (int j = 0; j < siz[i]; ++ j){
            auto [y, w] = fishes[i][j];
            if (y == N) y ++;
            while (ptr < siz[i - 1] && fishes[i - 1][ptr].first < y){
                val_up = max(val_up, dp[i - 1][0][ptr]);
                val_up += fishes[i - 1][ptr].second;
                ptr ++;
            }
            dp[i][0][j] = val_up;
        }

        long long val_down = 0;
        ptr = siz[i - 1] - 1;
        for (int j = siz[i] - 1; j >= 0; -- j){
            auto [y, w] = fishes[i][j];
            while (ptr >= 0 && fishes[i - 1][ptr].first > y){
                val_down = max(val_down, dp[i - 1][1][ptr]);
                ptr --;
            }
            val_down += w;
            dp[i][1][j] = val_down;
        }

        maxl(dp[i][1][siz[i] - 1], dp[i][0][siz[i] - 1]);
        maxl(dp[i][1][siz[i] - 1], dp[i - 1][1][0]);
        maxl(dp[i][0][0], dp[i - 1][1][0]);
    }

    return max(dp[N - 1][0][siz[N - 1] - 1], dp[N - 1][1][0]);
}

• 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