Submission #769182

#	Time	Username	Problem	Language	Result	Execution time	Memory
769182		t6twotwo	Carnival Tickets (IOI20_tickets)	C++17	55 / 100	593 ms	72340 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll find_maximum(int K, vector<vector<int>> x) {
    int N = x.size();
    int M = x[0].size();
    if (M == 1) {
        allocate_tickets(vector(N, vector{0}));
        vector<int> v(N);
        for (int i = 0; i < N; i++) {
            v[i] = x[i][0];
        }
        sort(v.begin(), v.end());
        ll s = 0;
        for (int i = 0; i < N; i++) {
            s += abs(v[N / 2] - v[i]);
        }
        return s;
    }
    if (K == 1) {
        vector dp(N + 1, vector<ll>(N / 2 + 1, -1e18));
        dp[0][0] = 0;
        for (int i = 0; i < N; i++) {
            for (int j = 0; j <= N / 2; j++) {
                if (j < N / 2) {
                    dp[i + 1][j + 1] = dp[i][j] + x[i][M - 1];
                }
                dp[i + 1][j] = max(dp[i + 1][j], dp[i][j] - x[i][0]);
            }
        }
        vector a(N, vector<int>(M, -1));
        for (int i = N - 1, j = N / 2; i >= 0; i--) {
            if (dp[i][j] - x[i][0] == dp[i + 1][j]) {
                a[i][0] = 0;
            } else {
                a[i][M - 1] = 0;
                j--;
            }
        }
        allocate_tickets(a);
        return dp[N][N / 2];
    }
    if (K == M) {
        vector<tuple<int, int, int>> v;
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < M; j++) {
                v.emplace_back(x[i][j], i, j);
            }
        }
        sort(v.begin(), v.end());
        vector f(N, vector<bool>(M));
        ll ans = 0;
        for (int i = 0; i < N * M / 2; i++) {
            auto [t, x, y] = v[i];
            ans -= t;
        }
        for (int i = N * M / 2; i < N * M; i++) {
            auto [t, x, y] = v[i];
            ans += t;
            f[x][y] = 1;
        }
        vector a(N, vector<int>(M));
        int x = 0, y = K - 1;
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < M; j++) {
                if (!f[i][j]) {
                    a[i][j] = y--;
                } else {
                    a[i][j] = x++;
                }
                if (y == -1) {
                    y = K - 1;
                }
                if (x == K) {
                    x = 0;
                }
            }
        }
        allocate_tickets(a);
        return ans;
    }
    vector<int> lo(N + 1), hi(N + 1);
    for (int i = 0; i < N; i++) {
        int cnt = count(x[i].begin(), x[i].end(), 1);
        lo[i + 1] = lo[i] + K - min(K, M - cnt);
        hi[i + 1] = hi[i] + min(cnt, K);
    }
    int ans = 0, q = 0;
    if (lo[N] <= N * K / 2 && N * K / 2 <= hi[N]) {
        ans = N * K / 2;
        q = N * K / 2;
    } else if (lo[N] > N * K / 2) {
        ans = N * K - lo[N];
        q = lo[N];
    } else {
        ans = q = hi[N];
    }
    int s = 0, t = K - 1;
    vector a(N, vector<int>(M, -1));
    for (int i = N - 1; i >= 0; i--) {
        int cnt = count(x[i].begin(), x[i].end(), 1);
        for (int j = K - min(K, M - cnt); j <= min(cnt, K); j++) {
            if (lo[i] <= q - j && q - j <= hi[i]) {
                for (int k = 0; k < K - j; k++) {
                    a[i][k] = s++;
                    if (s == K) {
                        s = 0;
                    }
                }
                for (int k = M - 1; k >= M - j; k--) {
                    a[i][k] = t--;
                    if (t == -1) {
                        t = K - 1;
                    }
                }
                q -= j;
                break;
            }
        }
    }
    allocate_tickets(a);
    return ans;
}

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