Submission #782409

#	Time	Username	Problem	Language	Result	Execution time	Memory
782409		jasmin	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	1694 ms	196384 KiB

tickets

#include "tickets.h"
#include<bits/stdc++.h>
using namespace std;
 
long long find_maximum(int k, std::vector<std::vector<int>> x) {
    int n=x.size();
    int m=x[0].size();
 
	vector<vector<int> > answer(n, vector<int> (m, -1));
    long long ans=0;
    vector<pair<int, pair<int,int> > > sorted;
    vector<set<pair<int,int> > > smaller(k);
    for(int i=0; i<n; i++){
        for(int j=0; j<k; j++){
            ans-=x[i][j];
            int indswap=m-(k-j);
            sorted.push_back({x[i][j]+x[i][indswap], {i, j}});
            answer[i][j]=j;
            smaller[j].insert({i, j});
        }
    }
    sort(sorted.begin(), sorted.end());
    reverse(sorted.begin(), sorted.end());
 
    //cout << ans << "\n";
 
    vector<set<pair<int,int> > > bigger(k);
    for(int i=0; i<(n*k)/2; i++){
 
        int gain=sorted[i].first;
        auto [ind, j]=sorted[i].second;
 
        int indswap = m-(k-j);
 
        ans += gain;
        smaller[j].erase({ind, j});
        bigger[j].insert({ind, indswap});
      swap(answer[ind][j], answer[ind][indswap]);
 
        //cout << "swap " << ind << " " << j << " => " << ans << "\n";
    }
 
    vector<int> manybig;
    vector<int> manysmall;
    for(int i=0; i<k; i++){
        if(bigger[i].size()>(n/2)){
            manybig.push_back(i);
        }
        else if(bigger[i].size()<(n/2)){
            manysmall.push_back(i);
        }
    }
 
    int mom=0;
    for(auto i: manybig){
 
        int cnt=0;
        while(bigger[i].size()-cnt > (n/2)){
 
            vector<pair<int,int> > gone;
            int inds=manysmall[mom];
 
            for(auto [ind, j]: bigger[i]){
                if(bigger[i].size()-cnt==(n/2)) break;
 
                auto it=smaller[inds].lower_bound({ind, 0});
 
                if(it!=smaller[inds].end() && (*it).first==ind){
                    swap(answer[ind][j], answer[ind][(*it).second]);
 
                    smaller[inds].erase(*it);
                    gone.push_back({ind, j});
                    cnt++;
                }
 
                if(smaller[manysmall[mom]].size()==(n/2)){
                    mom++;
                    break;
                }
            }
 
            for(auto e: gone){
                bigger[i].erase(e);
            }
            cnt=0;
        }
    }
 
    allocate_tickets(answer);
    return ans;
}

Compilation message (stderr)

tickets.cpp: In function 'long long int find_maximum(int, std::vector<std::vector<int> >)':
tickets.cpp:46:28: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   46 |         if(bigger[i].size()>(n/2)){
      |            ~~~~~~~~~~~~~~~~^~~~~~
tickets.cpp:49:33: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   49 |         else if(bigger[i].size()<(n/2)){
      |                 ~~~~~~~~~~~~~~~~^~~~~~
tickets.cpp:58:36: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   58 |         while(bigger[i].size()-cnt > (n/2)){
      |               ~~~~~~~~~~~~~~~~~~~~~^~~~~~~
tickets.cpp:64:40: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   64 |                 if(bigger[i].size()-cnt==(n/2)) break;
      |                    ~~~~~~~~~~~~~~~~~~~~^~~~~~~
tickets.cpp:76:50: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   76 |                 if(smaller[manysmall[mom]].size()==(n/2)){
      |                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 14 / 14
• Subtask 4: 14 / 14
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23
• Subtask 7: 10 / 10