Submission #429129

#	Time	Username	Problem	Language	Result	Execution time	Memory
429129		ACmachine	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	1220 ms	96828 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
using namespace std;
#define FOR(i, j, k, l) for(int i = (j); i < (k); i += (l))
#define FORD(i, j, k, l) for(int i = (j); i >= (k); i -= (l))
#define REP(i, n) FOR(i, 0, n, 1)
#define REPD(i, n) FORD(i, n, 0, 1)
typedef long long ll;
#define pb push_back
long long find_maximum(int k, vector<vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
    // think in terms of change;
    vector<array<int, 3>> change;
    ll sum = 0; 
    REP(i, n){
        REP(j, k){
            change.pb({x[i][j] + x[i][m - k + j], i, j});
            sum -= x[i][j];
        }
    }
    sort(change.begin(), change.end(), greater<array<int, 3>>());
    vector<int> upper(n, k);
    vector<vector<array<int, 2>>> rows(n);  
    REP(i, n * k / 2){
        auto v = change[i];
        sum += v[0];
        upper[v[1]] = v[2];
    }
    REP(i, n){
        REP(j, upper[i]){
            rows[i].pb({x[i][j], j});
        }
    }
    REP(i, n){
        REP(j, k - upper[i]){
            rows[i].pb({x[i][m - 1 - j], m - 1 - j}); 
        }
    }
    vector<int> cnts = upper; // cnt smaller available
	vector<vector<int>> answer(n, vector<int>(m, -1));
    vector<int> sorted(n);
    iota(sorted.begin(), sorted.end(), 0);
    auto cmp = [&](int f, int s){
        return cnts[f] > cnts[s];
    };
    REP(i, k){
        sort(sorted.begin(), sorted.end(), cmp);
        REP(j, n / 2){
            cnts[sorted[j]]--;
            int row = sorted[j]; int col = rows[row][cnts[row]][1];
            answer[row][col] = i;
        }
        FOR(j, n / 2, n, 1){
            int row = sorted[j]; 
            int smaller_taken = upper[row] - cnts[row];
            int col = k - 1 - i + smaller_taken;
            col = rows[row][col][1];
            answer[row][col] = i;
        }
    }
	
	allocate_tickets(answer);
	return sum;
}

• 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