Submission #792464

#	Time	Username	Problem	Language	Result	Execution time	Memory
792464		t6twotwo	Abracadabra (CEOI22_abracadabra)	C++17	50 / 100	273 ms	33936 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
void shuffle(vector<int> &a) {
    int n = a.size();
    vector<int> b;
    int j = n / 2;
    for (int i = 0; i < n / 2; i++) {
        while (j < n && a[j] < a[i]) {
            b.push_back(a[j++]);
        }
        b.push_back(a[i]);
    }
    for (int i = j; i < n; i++) {
        b.push_back(a[i]);
    }
    swap(a, b);
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N, Q;
    cin >> N >> Q;
    vector<int> A(N);
    for (int &x : A) {
        cin >> x;
    }
    if (N <= 1000) {
        vector<vector<int>> T;
        do {
            T.push_back(A);
            shuffle(A);
        } while (A != T.back());
        int M = T.size();
        while (Q--) {
            int t, i;
            cin >> t >> i;
            t = min(t, M - 1);
            i--;
            cout << T[t][i] << "\n";
        }
        return 0;
    }
    vector<int> q(Q);
    int t;
    for (auto &x : q) {
        cin >> t >> x;
        x--;
    }
    if (t == 0) {
        for (int x : q) {
            cout << A[x] << "\n";
        }
        return 0;
    }
    vector<int> f(N, N), stk;
    for (int i = N - 1; i >= 0; i--) {
        while (!stk.empty() && A[stk.back()] < A[i]) {
            stk.pop_back();
        }
        if (!stk.empty()) {
            f[i] = stk.back();
        }
        stk.push_back(i);
    }
    set<tuple<int, int, int>> s, s2;
    for (int i = 0; i < N; i = f[i]) {
        s.emplace(A[i], i, f[i]);
    }
    int T = N;
    while (t--) {
        while (1) {
            auto [_, l, r] = *prev(s.end());
            if (T - r + l < N / 2) {
                break;
            }
            T -= r - l;
            s2.insert(*prev(s.end()));
            s.erase(prev(s.end()));
        }
        if (T == N / 2) {
            break;
        }
        auto [v, l, r] = *prev(s.end());
        s.erase(prev(s.end()));
        int m = r - T + N / 2;
        s.emplace(v, l, m);
        for (int i = m; i < r; i = f[i]) {
            s.emplace(A[i], i, min(r, f[i]));
        }
    }
    s.insert(s2.begin(), s2.end());
    vector<int> B;
    for (auto [_, l, r] : s) {
        B.insert(B.end(), A.begin() + l, A.begin() + r);
    }
    for (int x : q) {
        cout << B[x] << "\n";
    }
    return 6/22;
}

• Subtask 1: 10 / 10
• Subtask 2: 40 / 40
• Subtask 3: 0 / 25
• Subtask 4: 0 / 25