Submission #627749

#	Time	Username	Problem	Language	Result	Execution time	Memory
627749		tutis	Catfish Farm (IOI22_fish)	C++17	100 / 100	276 ms	42012 KiB

fish

#include "fish.h"

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
long long max_weights(int N, int MM, std::vector<int> X, std::vector<int> Y,
                      std::vector<int> W) {
    vector<pair<int, ll>>P[N];
    vector<int>Q_[N + 4];
    vector<int>*Q = Q_ + 2;
    for (int i = 0; i < MM; i++)
    {
        P[X[i]].push_back({Y[i], W[i]});
        Q[X[i]].push_back(Y[i]);
    }
    for (int i = -1; i <= N; i++)
    {
        Q[i].push_back(N);
    }
    for (int i = 0; i < N; i++)
    {
        sort(P[i].begin(), P[i].end());
        for (int j = 1; j < (int)P[i].size(); j++)
            P[i][j].second += P[i][j - 1].second;
        sort(Q[i].begin(), Q[i].end());
    }
    ll dp_[N + 3];
    ll* dp = dp_ + 2;
    for (int i = -2; i <= N; i++)
        dp[i] = 0;
    vector<ll> u[N];
    vector<ll> d[N];
    auto get = [&](int x, int y)->ll
    {
        if (x < 0 || x >= N)
            return 0;
        auto it = lower_bound(P[x].begin(), P[x].end(), make_pair(y + 1, -1ll));
        if (it == P[x].begin())
            return 0;
        it--;
        return it->second;
    };
    ll vv = 0;
    for (int x = 0; x < N; x++)
    {
        dp[x] = dp[x - 1];
        dp[x] = max(dp[x], vv);
        vv = 0;
        for (int y : Q[x - 1])
            u[x].push_back(0);
        for (int y : Q[x + 1])
            d[x].push_back(0);
        for (int i = 0; i < (int)Q[x - 1].size(); i++)
        {
            ll&v = u[x][i];
            int y = Q[x - 1][i];
            v = max(v, dp[x - 1]);
            v = max(v, dp[x - 2] + get(x - 1, y));
        }
        if (x != 0)
        {
            ll mx = -1e18;
            int j = 0;
            for (int i = 0; i < (int)Q[x - 1].size(); i++)
            {
                ll&v = u[x][i];
                int y = Q[x - 1][i];
                while (j < (int)Q[x - 2].size() && Q[x - 2][j] < y)
                {
                    mx = max(mx, u[x - 1][j] - get(x - 1, Q[x - 2][j]));
                    j++;
                }
                v = max(v, mx + get(x - 1, y));
            }
        }
        for (int i = 0; i < (int)Q[x - 1].size(); i++)
        {
            ll&v = u[x][i];
            int y = Q[x - 1][i];
            dp[x] = max(dp[x], v);
            vv = max(vv, v + get(x + 1, y));
        }
        for (int i = 0; i < (int)Q[x + 1].size(); i++)
        {
            ll&v = d[x][i];
            int y = Q[x + 1][i];
            if (y == N)
                v = max(v, u[x].back());
            v = max(v, dp[x - 1]);
            v = max(v, dp[x - 2] + get(x - 1, y));
        }
        if (x != 0)
        {
            int j = (int)Q[x].size() - 1;
            ll mx = -1e18;
            for (int i = (int)Q[x + 1].size() - 1; i >= 0; i--)
            {
                ll&v = d[x][i];
                int y = Q[x + 1][i];
                while (j >= 0 && Q[x][j] > y)
                {
                    mx = max(mx, d[x - 1][j] + get(x, Q[x][j]));
                    j--;
                }
                v = max(v, mx - get(x, y));
            }
        }
        for (int i = 0; i < (int)Q[x + 1].size(); i++)
        {
            ll&v = d[x][i];
            int y = Q[x + 1][i];
            dp[x] = max(dp[x], v);
            vv = max(vv, v + get(x + 1, y));
        }
    }
    return dp[N - 1];
}

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:49:18: warning: unused variable 'y' [-Wunused-variable]
   49 |         for (int y : Q[x - 1])
      |                  ^
fish.cpp:51:18: warning: unused variable 'y' [-Wunused-variable]
   51 |         for (int y : Q[x + 1])
      |                  ^

• 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