Submission #303151

#	Time	Username	Problem	Language	Result	Execution time	Memory
303151		12tqian	Carnival Tickets (IOI20_tickets)	C++14	27 / 100	727 ms	51524 KiB

tickets

#ifdef LOCAL
#else
#include "tickets.h"
#endif
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

#ifdef LOCAL
#define dbg(...) debug(#__VA_ARGS__, __VA_ARGS__);
#else
#define dbg(...) 17;
#endif

template<typename T, typename S> ostream& operator << (ostream &os, const pair<T, S> &p) { return os << "(" << p.first << ", " << p.second << ")"; }
template<typename C, typename T = decay<decltype(*begin(declval<C>()))>, typename enable_if<!is_same<C, string>::value>::type* = nullptr>
ostream& operator << (ostream &os, const C &c) { bool f = true; os << "{"; for (const auto &x : c) { if (!f) os << ", "; f = false; os << x; } return os << "}"; }
template<typename T> void debug(string s, T x) { cerr << s << " = " << x << "\n"; }
template<typename T, typename... Args> void debug(string s, T x, Args... args) { cerr << s.substr(0, s.find(',')) << " = " << x << " | "; debug(s.substr(s.find(',') + 2), args...); }
#ifdef LOCAL
void allocate_tickets(vector<vector<int>> s) {
    return;
}
#else
#endif

ll find_maximum(int k, vector<vector<int>> x) {
    const ll INF = 1e15;
    int n = x.size();
    int m = x[0].size();
    vector<vector<int>> res(n, vector<int>(m, -1));
    if (m == 1) {
        vector<int> all;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                res[i][j] = 0;
                all.push_back(x[i][j]);
            }
        }
        sort(all.begin(), all.end());
        ll ans = 0;
        for (int i = 0; i < n; i++) {
            if (i < n / 2) {
                ans -= all[i];
            } else {
                ans += all[i];
            }
        }
        allocate_tickets(res);
        return ans;

    } else if (k == 1) {
        vector<array<ll, 2>> use;
        for (int i = 0; i < n; i++) {
            use.push_back({x[i][0] + x[i][m - 1], i});
        }
        sort(use.begin(), use.end());
        ll ans = 0;
        for (int i = 0; i < n; i++) {
            if (i < n / 2) {
                res[use[i][1]][0] = 0;
                ans -= x[use[i][1]][0];
            } else {
                res[use[i][1]][m - 1] = 0;
                ans += x[use[i][1]][m - 1];
            }
        }
        allocate_tickets(res);
        return ans;
    } else {
        vector<int> lef(n);
        for (int i = 0; i < n; i++) {
            if (i % 2 == 0) {
                lef[i] = k / 2;
            } else {
                lef[i] = k - k / 2;
            }
        }
        set<array<ll, 2>> shift_left;
        set<array<ll, 2>> shift_right;
        auto calc_right = [&](int id) -> ll {
            // you want to move something to minus
            if (lef[id] == k) {
                // never advantageous
                return INF;
            } else {
                // what you'll get
                int rig = k - lef[id];
                return x[id][lef[id]] + x[id][m - rig];
            }
        };
        auto calc_left = [&](int id) -> ll {
            // you want to move something to plus
            if (lef[id] == 0) {
                return -INF;
            } else {
                int rig = k - lef[id];
                return x[id][lef[id] - 1] + x[id][m - rig - 1];
            }
        };
        auto modify = [&](int id, int change) {
            ll l = calc_left(id);
            ll r = calc_right(id);
            shift_left.erase({l, id});
            shift_right.erase({r, id});
            lef[id] += change;
            l = calc_left(id);
            r = calc_right(id);
            shift_left.insert({l, id});
            shift_right.insert({r, id});
        };
        for (int i = 0; i < n; i++) {
            shift_left.insert({calc_left(i), i});
            shift_right.insert({calc_right(i), i});
        }
        while (*shift_right.begin() < *shift_left.rbegin()) {
            int add = (*shift_right.begin())[1];
            int sub = (*shift_left.rbegin())[1];
            modify(sub, -1);
            modify(add, 1);
        }
        ll ans = 0;
        vector<array<int, 3>> neg;
        vector<array<int, 3>> pos;
        vector<int> neg_filled(k);
        vector<int> pos_filled(k);
        int neg_cur = 0;
        int pos_cur = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < lef[i]; j++) {
                ans -= x[i][j];
                if (neg_filled[neg_cur] == n / 2) {
                    neg_cur++;
                }
                neg_filled[neg_cur]++;
                res[i][j] = neg_cur;
                neg.push_back({x[i][j], i, j});
            }
            for (int j = m - lef[i]; j < m; j++) {
                ans += x[i][j];
                if (pos_filled[pos_cur] == n / 2) {
                    pos_cur++;
                }
                pos_filled[pos_cur]++;
                res[i][j] = pos_cur;
                pos.push_back({x[i][j], i, j});
            }
        }
        sort(neg.begin(), neg.end());
        sort(pos.begin(), pos.end());
        assert(neg.back()[0] <= pos[0][0]);
        // allocation
        allocate_tickets(res);
        return ans;
    }
}
#ifdef LOCAL
int main() {
//    freopen("file.in", "r", stdin);
//    string line; cin >> line;
    int n, m, k; cin >> n >> m >> k;
    vector<vector<int>> s(n, vector<int>(m, 0));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> s[i][j];
        }
    }
    cout << find_maximum(k, s) << '\n';;
    return 0;
}
#else
#endif

• 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