Submission #1068554

#	Time	Username	Problem	Language	Result	Execution time	Memory
1068554		Unforgettablepl	Catfish Farm (IOI22_fish)	C++17	52 / 100	1107 ms	2097152 KiB

fish

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

long long max_weights(int N, int M,vector<int> X,vector<int> Y,
                      vector<int> W){
    vector DP(N+1,vector(2,0ll));
    vector<vector<pair<int,long long>>> pref(N+2);
    for(int i=0;i<=N+1;i++)pref[i].emplace_back(0,0);
    vector<vector<int>> special_points(N+2);
    for(int i=1;i<=N+1;i++)special_points[i].emplace_back(0);
    for(int i=1;i<=N+1;i++)special_points[i].emplace_back(N);
    vector transition1(N+1,vector(N+1,0ll));
    vector transition2(N+1,vector(N+1,0ll));
    vector transition3(N+1,vector(N+1,0ll));
    vector transition4(N+1,vector(N+1,0ll));
    for(int i=0;i<M;i++) {
        pref[X[i]+1].emplace_back(Y[i]+1,W[i]);
        special_points[X[i]+1].emplace_back(Y[i]);
    }
    for(int i=1;i<=N+1;i++) {
        sort(special_points[i].begin(),special_points[i].end());
        special_points[i].erase(unique(special_points[i].begin(),special_points[i].end()),special_points[i].end());
        sort(pref[i].begin(), pref[i].end());
        for(int j=1;j<pref[i].size();j++)pref[i][j].second+=pref[i][j-1].second;
    }
    auto getpref = [&](int i,int j) {
        auto iter = lower_bound(pref[i].begin(),pref[i].end(),make_pair(j+1,-1ll));
        iter--;
        return iter->second;
    };
    for(int i=2;i<=N;i++) {
        for(int j=0;j<=N;j++) {
            if(i!=2)DP[j][1]=max(DP[j][1],-getpref(i,j)+transition1[i-1][j]);
            else DP[j][1]=max(DP[j][1],getpref(i,N)-getpref(i,j));
            if(i>2) {
                if(i!=3) {
                    DP[j][0]=max(DP[j][0],getpref(i-1,j)+transition2[i-2][j]);
                    DP[j][0]=max(DP[j][0],transition3[i-2][j]);
                }
                else DP[j][0]=max(DP[j][0],getpref(i-1,N));
            }
            if(i!=2)DP[j][0]=max(DP[j][0],getpref(i-1,j)+transition4[i-1][j]);
            else DP[j][0]=max(DP[j][0],getpref(i-1,j));
            transition1[i][j]=getpref(i+1,j)+max(DP[j][0],DP[j][1]);
            transition2[i][j]=max(DP[j][0],DP[j][1]);
            transition3[i][j]=getpref(i+1,j)+max(DP[j][0],DP[j][1]);
            transition4[i][j]=-getpref(i,j)+DP[j][0];
        }
        for(int j=N-1;j>=0;j--)transition1[i][j]=max(transition1[i][j],transition1[i][j+1]);
        for(int j=1;j<=N;j++)transition2[i][j]=max(transition2[i][j],transition2[i][j-1]);
        for(int j=N-1;j>=0;j--)transition3[i][j]=max(transition3[i][j],transition3[i][j+1]);
        for(int j=1;j<=N;j++)transition4[i][j]=max(transition4[i][j],transition4[i][j-1]);
    }
    long long ans = 0;
    for(int j=0;j<=N;j++)ans=max(ans,DP[j][0]);
    for(int j=0;j<=N;j++)ans=max(ans,DP[j][1]);
    return ans;
}

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:25:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |         for(int j=1;j<pref[i].size();j++)pref[i][j].second+=pref[i][j-1].second;
      |                     ~^~~~~~~~~~~~~~~

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