Submission #1194184

#	Time	Username	Problem	Language	Result	Execution time	Memory
1194184		LucaIlie	Olympiads (BOI19_olympiads)	C++17	100 / 100	1451 ms	127320 KiB

olympiads

#include <bits/stdc++.h>
using namespace std;
using ull = unsigned long long;

#if defined(__GNUC__)
#pragma GCC optimize("Ofast,unroll-loops,inline,fast-math")
#pragma GCC target("sse4.2,avx,avx2,bmi,bmi2,popcnt")
#endif

struct Node {
    ull st;
    int sc;
};
struct Asc {
    bool operator()(Node const &a, Node const &b) const {
        return (a.sc < b.sc) || (a.sc == b.sc && a.st < b.st);
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, K;
    long long C;
    cin >> N >> K >> C;

    static int score[500][6];
    for (int i = 0; i < N; i++)
        for (int j = 0; j < K; j++)
            cin >> score[i][j];

    // precompute N^i
    ull powN[6];
    powN[0] = 1;
    for (int i = 1; i < K; i++)
        powN[i] = powN[i - 1] * (ull)N;

    // 1) Greedy start‐team: pick best unused per event
    int start[6];
    {
        bool used[500] = {};
        for (int e = 0; e < K; e++) {
            int bj = 0, bs = -1;
            for (int j = 0; j < N; j++) {
                if (!used[j] && score[j][e] > bs) {
                    bs = score[j][e];
                    bj = j;
                }
            }
            used[bj] = true;
            start[e] = bj;
        }
        sort(start, start + K);
    }

    auto encode = [&](int a[6]) {
        ull s = 0;
        for (int i = 0; i < K; i++)
            s += powN[i] * (ull)a[i];
        return s;
    };
    auto fullScore = [&](int a[6]) {
        int tot = 0;
        for (int e = 0; e < K; e++) {
            int m = 0;
            for (int i = 0; i < K; i++) {
                int v = score[a[i]][e];
                if (v > m) m = v;
            }
            tot += m;
        }
        return tot;
    };

    // frontier: keep at most (C-iter) best candidates
    multiset<Node, Asc> pq;
    unordered_set<ull> vis;
    vis.reserve((size_t)C * K + 16);

    // seed it
    ull s0 = encode(start);
    int sc0 = fullScore(start);
    pq.insert({s0, sc0});
    vis.insert(s0);  // ← mark the start‐team visited!

    int cur[6], base[6], baseMax[6], newt[6];
    bitset<500> in;

    // 2) Expand C‐1 times
    for (long long iter = 1; iter < C; iter++) {
        // pop current best
        auto itBest = prev(pq.end());
        Node top = *itBest;
        pq.erase(itBest);

        // decode st → cur[]
        {
            ull x = top.st;
            for (int i = 0; i < K; i++) {
                cur[i] = int(x % (ull)N);
                x /= (ull)N;
            }
        }

        size_t limit = C - iter;
        // for each position we remove
        for (int rem = 0; rem < K; rem++) {
            // build base[0..K-2]
            for (int i = 0, t = 0; i < K; i++) {
                if (i != rem) base[t++] = cur[i];
            }
            // compute per-event maxima & mark “in base”
            in.reset();
            for (int e = 0; e < K; e++)
                baseMax[e] = 0;
            for (int i = 0; i < K - 1; i++) {
                int b = base[i];
                in.set(b);
                for (int e = 0; e < K; e++) {
                    int v = score[b][e];
                    if (v > baseMax[e]) baseMax[e] = v;
                }
            }
            int bs = 0;
            for (int e = 0; e < K; e++)
                bs += baseMax[e];

            // try inserting any j∉base
            for (int j = 0; j < N; j++) {
                if (in.test(j)) continue;
                // compute delta
                int delta = 0;
                for (int e = 0; e < K; e++) {
                    int v = score[j][e];
                    if (v > baseMax[e]) delta += v - baseMax[e];
                }
                // merge j into sorted base → newt
                bool done = false;
                for (int p = 0, q = 0; p < K; p++) {
                    if (!done && (q == K - 1 || j < base[q])) {
                        newt[p] = j;
                        done = true;
                    } else {
                        newt[p] = base[q++];
                    }
                }
                // encode + dedupe
                ull st2 = 0;
                for (int i = 0; i < K; i++)
                    st2 += powN[i] * (ull)newt[i];
                if (!vis.insert(st2).second)
                    continue;

                Node nd{st2, bs + delta};
                // bounded‐insert
                if (pq.size() < limit) {
                    pq.insert(nd);
                } else {
                    auto itMin = pq.begin();
                    if (nd.sc > itMin->sc) {
                        pq.erase(itMin);
                        pq.insert(nd);
                    }
                }
            }
        }
    }

    // now the top is the C-th best
    cout << prev(pq.end())->sc << "\n";
    return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 31 / 31
• Subtask 3: 24 / 24
• Subtask 4: 32 / 32