Submission #1178692

#	Time	Username	Problem	Language	Result	Execution time	Memory
1178692		DeMen100ns	Olympiads (BOI19_olympiads)	C++20	13 / 100	4 ms	840 KiB

olympiads

/*
Author : DeMen100ns (Vo Khac Trieu)
School: University of Science, VNU-HCM
Aim: 
- International Grandmaster Codeforces (2600) 
- ICPC World Final 2025
*/

#include <bits/stdc++.h>

#define int long long

using namespace std;

const long long INF = numeric_limits<long long>::max() / 2;
const int INF_int = 1e9 + 7;

struct State{
    int val, forced;
    vector <int> v;
    vector <bool> ban;

    State(vector <int> v, vector<bool> ban, int forced, vector <vector<int>> &a, int k)
    : v(v), ban(ban), forced(forced){
        vector <int> ans(k, 0);
        for(int i = 0; i < k; ++i){
            for(int j = 0; j < k; ++j){
                ans[i] = max(ans[i], a[v[j]][i]);
            }
        }
        val = accumulate(ans.begin(), ans.end(), 0);
    }

    bool operator <(const State &a) const{
        return val < a.val;
    }
};

mt19937_64 rng(1234);

long long randint(long long l, long long r){
    return uniform_int_distribution <long long> (l, r) (rng);
}

double randdouble(double l, double r){
    return uniform_real_distribution <double> (l, r) (rng);
}

void solve(){
    int n, k, c; cin >> n >> k >> c;
    vector <vector<int>> a(n, vector<int>(k, 0));
    vector <vector<int>> order(n, vector<int>(k, 0));
    vector <int> H(n);
    vector <vector<array<int, 2>>> value(k);

    for(int i = 0; i < n; ++i){
        for(int j = 0; j < k; ++j) cin >> a[i][j];
        H[i] = randint(5e17, 1e18);
    }

    auto hash_state = [&](vector <int> v){
        int hsh = 0;
        for(int i : v) hsh ^= H[i];
        return hsh;
    };
    
    vector <int> opt;
    vector <bool> choose(n, 0);
    for(int i = 0; i < k; ++i){
        vector <array<int, 2>> v;
        for(int j = 0; j < n; ++j){
            v.push_back({a[j][i], j});
        }
        sort(v.begin(), v.end(), greater<array<int, 2>>());
        value[i] = v;
        int ct = 0;
        bool g = false;
        for(auto[val, id]: v){
            order[id][i] = ++ct;
            if (!choose[id] && !g){
                g = true;
                choose[id] = true;
                opt.push_back(id);
            }
        }
    }
    sort(opt.begin(), opt.end());

    priority_queue<State, vector<State>> pq;
    unordered_set <int> exist;

    pq.push(State(opt, vector<bool>(n, 0), 0, a, k));
    exist.insert(hash_state(opt));

    while (c--){
        State u = pq.top(); pq.pop();

        // cerr << "---" << endl << u.val << endl;
        // for(int i : u.v) cerr << i << " "; cerr << endl;

        if (c == 0){
            cout << u.val << endl;
            return;
        }

        vector <bool> nban = u.ban;

        for(int id = u.forced; id < k; ++id){
            nban[u.v[id]] = true;

            vector <int> opt;
            if (id > 0) opt = {u.v.begin(), u.v.begin() + id};

            for(int event = id; event < k; ++event){
                for(int i = 0; i < n; ++i){
                    int new_i = value[event][i][1];
                    bool valid = !nban[new_i];
                    for(int j : opt) valid &= new_i != j;
                    if (valid){
                        opt.push_back(new_i);
                        break;
                    }
                }
            }

            // cerr << id << ": \n";
            // for(int i : opt) cerr << i << " "; cerr << '\n';

            if (opt.size() == k){
                pq.push(State(opt, nban, id, a, k));
            }
        }

        assert(!pq.empty());

       // cerr << pq.size() << endl;
    }
}

signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

    int t = 1; // cin >> t;
    for(int test = 1; test <= t; ++test){
        solve();
    }
}

• Subtask 1: 13 / 13
• Subtask 2: 0 / 31
• Subtask 3: 0 / 24
• Subtask 4: 0 / 32