Submission #656346

#	Time	Username	Problem	Language	Result	Execution time	Memory
656346		Lobo	Catfish Farm (IOI22_fish)	C++17	81 / 100	1103 ms	252456 KiB

fish

#include "fish.h"
#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3","unroll-loops")
// #define int long long
#define ll long long
#define pb push_back
#define mp make_pair
#define fr first
#define sc second
#define all(x) x.begin(),x.end()

const int maxn = 1e5+10;
// const int inf = 1e18+10;

int n, m;
vector<vector<ll>> dp[maxn];
map<int,ll> pf[maxn], pfmx0[maxn], pfmx1[maxn], sfmx0[maxn];
vector<pair<int,int>> fish[maxn]; // fishs from column i
vector<int> hr[maxn]; // important heights from column i, the ones that can be chosen

long long max_weights(int32_t N, int32_t M, vector<int32_t> X, vector<int32_t> Y, vector<int32_t> W) {
    n = N;
    m = M;

    for(int i = 0; i < m; i++) {
        fish[X[i]+1].pb(mp(Y[i]+1,W[i]));
        hr[X[i]+1].pb(Y[i]);
    }

    for(int i = 0; i <= n; i++) {
        hr[i].pb(0);
        hr[i].pb(n);
        sort(all(hr[i]));
        sort(all(fish[i]));
        hr[i].erase(unique(all(hr[i])),hr[i].end());
        // Store only the relevant heights

        for(int j = 0; j < hr[i].size(); j++) {
            dp[i].pb({0,0});
        }
    }

    for(int i = 1; i <= n; i++) {
        for(auto j : hr[i-1]) pf[i][j] = 0;
        for(auto j : hr[i]) pf[i][j] = 0;
        for(auto j : hr[i+1]) pf[i][j] = 0;

        for(auto aux : fish[i]) {
            int y = aux.fr;
            int w = aux.sc;
            pf[i][y]+= w;
        }
        // Do a prefix sum on the weight of the fishs
        pf[i][0] = 0;
        for(auto it = next(pf[i].begin()); it != pf[i].end(); it++) {
            it->sc+= prev(it)->sc;
        }
    }

    // dp[i][h0][0/1] = until i, with h[i] = hr[i][h0] 
    // and it's greater/smaller tha the previous

    // dp[1][h0][0/1] = 0
    for(int h0 = 0; h0 < hr[1].size(); h0++) {
        dp[1][h0][0] = 0;
        dp[1][h0][1] = 0;
        pfmx0[1][hr[1][h0]] = max(pfmx0[1][hr[1][h0]],dp[1][h0][0]-pf[1][hr[1][h0]]);
        sfmx0[1][hr[1][h0]] = max(sfmx0[1][hr[1][h0]],dp[1][h0][0]+pf[1+1][hr[1][h0]]);
        sfmx0[1][hr[1][h0]] = max(sfmx0[1][hr[1][h0]],dp[1][h0][1]+pf[1+1][hr[1][h0]]);
    }

    for(auto j : hr[2]) {
        pfmx0[1][j] = max(pfmx0[1][j],0LL);
    }
    for(auto it = next(pfmx0[1].begin()); it != pfmx0[1].end(); it++) {
        it->sc = max(it->sc,prev(it)->sc);
    }

    for(auto j : hr[2]) {
        sfmx0[1][j] = max(sfmx0[1][j],0LL);
    }
    auto it = prev(prev(sfmx0[1].end()));
    while(true) {
        it->sc = max(it->sc,next(it)->sc);
        if(it == sfmx0[1].begin()) break;
        it = prev(it);
    }

    for(int i = 2; i <= n; i++) {
        for(int h0 = 0; h0 < hr[i].size(); h0++) {
            // It's greater than the previous
            auto it = prev(upper_bound(all(hr[i-1]),hr[i][h0]));
            dp[i][h0][0] = pfmx0[i-1][*it] + pf[i-1][hr[i][h0]];

            if(i != 2) {
                it = prev(upper_bound(all(hr[i-2]),hr[i][h0]));
                dp[i][h0][0] = max(dp[i][h0][0],pfmx1[i-2][*it] + pf[i-1][hr[i][h0]]);
            }

            // It's smaller than the previous
            it = lower_bound(all(hr[i-1]),hr[i][h0]);
            dp[i][h0][1] = sfmx0[i-1][*it] - pf[i][hr[i][h0]];

            pfmx0[i][hr[i][h0]] = max(pfmx0[i][hr[i][h0]],dp[i][h0][0]-pf[i][hr[i][h0]]);
            pfmx1[i][hr[i][h0]] = max(pfmx1[i][hr[i][h0]],max(dp[i][h0][1],dp[i][h0][0]));
            sfmx0[i][hr[i][h0]] = max(sfmx0[i][hr[i][h0]],max(dp[i][h0][0],dp[i][h0][1])+pf[i+1][hr[i][h0]]);
        }

        for(auto j : hr[i+1]) {
            // sfmx0[i][j] = max(sfmx0[i][j],0LL);
        }
        for(auto it = next(pfmx0[i].begin()); it != pfmx0[i].end(); it++) {
            it->sc = max(it->sc,prev(it)->sc);
        }

        for(auto j : hr[i+2]) {
            pfmx1[i][j] = max(pfmx1[i][j],0LL);
        }
        for(auto it = next(pfmx1[i].begin()); it != pfmx1[i].end(); it++) {
            it->sc = max(it->sc,prev(it)->sc);
        }
        auto it = prev(prev(sfmx0[i].end()));
        while(true) {
            it->sc = max(it->sc,next(it)->sc);
            if(it == sfmx0[i].begin()) break;
            it = prev(it);
        }
    }

    ll ans = 0;
    for(int h0 = 0; h0 < hr[n].size(); h0++) {
        ans = max(ans, dp[n][h0][0]);
        ans = max(ans, dp[n][h0][1]);
    }
    return ans;
}

Compilation message (stderr)

fish.cpp: In function 'long long int max_weights(int32_t, int32_t, std::vector<int>, std::vector<int>, std::vector<int>)':
fish.cpp:39:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |         for(int j = 0; j < hr[i].size(); j++) {
      |                        ~~^~~~~~~~~~~~~~
fish.cpp:65:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |     for(int h0 = 0; h0 < hr[1].size(); h0++) {
      |                     ~~~^~~~~~~~~~~~~~
fish.cpp:91:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |         for(int h0 = 0; h0 < hr[i].size(); h0++) {
      |                         ~~~^~~~~~~~~~~~~~
fish.cpp:110:18: warning: unused variable 'j' [-Wunused-variable]
  110 |         for(auto j : hr[i+1]) {
      |                  ^
fish.cpp:132:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  132 |     for(int h0 = 0; h0 < hr[n].size(); h0++) {
      |                     ~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 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: 0 / 16