Submission #1257005

#	Time	Username	Problem	Language	Result	Execution time	Memory
1257005		antonn	Carnival Tickets (IOI20_tickets)	C++20	27 / 100	3095 ms	73644 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>

#define all(a) a.begin(), a.end()
using namespace std;
typedef long long ll;

ll find_maximum(int k, vector<vector<int>> a) {
    int n = a.size();
    int m = a[0].size();
    vector<vector<ll>> pref(n + 1, vector<ll>(m + 1));
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            pref[i][j] = pref[i][j - 1] + a[i - 1][j - 1];
        }
    }
    auto smallest = [&](int i, int k) {
        return pref[i][k];
    };
    auto biggest = [&](int i, int k) {
        return pref[i][m] - pref[i][m - k];
    };
    vector<vector<int>> who(n + 1, vector<int>(n * k / 2 + 1, 0));
    vector<ll> dp(n * k / 2 + 1, -1e18);
    dp[0] = 0;
    for (int i = 1; i <= n; i++) {
        vector<ll> ndp(n * k / 2 + 1, -1e18);
        for (int j = 0; j <= n * k / 2; j++) {
            for (int h = 0; h <= k && h <= j; h++) {
                if (ndp[j] < dp[j - h] + biggest(i, h) - smallest(i, k - h)) {
                    ndp[j] = dp[j - h] + biggest(i, h) - smallest(i, k - h);
                    who[i][j] = h;
                }
            }
        }
        swap(dp, ndp);
    }
    vector<vector<int>> sol(n, vector<int>(m, -1));
    vector<int> small(k, 0), big(k, 0);
    ll ans = dp[n * k / 2];
    int i = n;
    int j = n * k / 2;
    while (i > 0) {
        int x = who[i][j];
        int r = 0;
        vector<bool> seen(k);
        for (int it = 0; it < m; it++) {
            if (it < k - x) {
                while (small[r] == n / 2 || seen[r]) {
                    r = (r + 1) % k;
                } 
                seen[r] = 1;
                sol[i - 1][it] = r;
                small[r]++;
            }
            if (m - it <= x) {
                while (big[r] == n / 2 || seen[r]) {
                    r = (r + 1) % k;
                } 
                seen[r] = 1;
                sol[i - 1][it] = r;
                big[r]++;
            }
        }
        i--;
        j -= x;
    }
    allocate_tickets(sol);
    return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10