Submission #792762

#	Time	Username	Problem	Language	Result	Execution time	Memory
792762		t6twotwo	Abracadabra (CEOI22_abracadabra)	C++17	100 / 100	530 ms	39928 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
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;
    }
    vector<int> queries(Q), ans(Q);
    vector<vector<int>> q(N + 1);
    for (int i = 0; i < Q; i++) {
        int t, p;
        cin >> t >> p;
        t = min(t, N);
        p--;
        queries[i] = p;
        if (t == 0) {
            ans[i] = A[p];
        } else {
            q[t].push_back(i);
        }
    }
    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);
    }
    vector<int> bit(N + 1);
    auto add = [&](int p, int x) {
        for (int i = p; i <= N; i += i & -i) {
            bit[i] += x;
        }
    };
    auto sum = [&](int p) {
        int s = 0;
        for (int i = p; i; i -= i & -i) {
            s += bit[i];
        }
        return s;
    };
    vector<int> L(N + 1), R(N + 1);
    set<tuple<int, int, int>> s, t;
    for (int i = 0; i < N; i = f[i]) {
        L[A[i]] = i;
        R[A[i]] = f[i];
        s.emplace(A[i], L[A[i]], R[A[i]]);
        add(A[i], R[A[i]] - L[A[i]]);
    }
    int T = N;
    for (int i = 1; i <= N; i++) {
        if (T > N / 2) {
            while (1) {
                auto [_, l, r] = *prev(s.end());
                if (T - r + l < N / 2) {
                    break;
                }
                T -= r - l;
                s.erase(prev(s.end()));
            }
            if (T > N / 2) {
                auto [v, l, r] = *prev(s.end());
                s.erase(prev(s.end()));
                int m = r - T + N / 2;
                s.emplace(v, l, m);
                add(v, m - r);
                R[v] = m;
                for (int i = m; i < r; i = f[i]) {
                    L[A[i]] = i;
                    R[A[i]] = min(r, f[i]);
                    s.emplace(A[i], L[A[i]], R[A[i]]);
                    add(A[i], R[A[i]] - L[A[i]]);
                }
            }
        }
        for (int k : q[i]) {
            int p = queries[k] + 1;
            int pos = 0, sum0 = 0;
            for (int i = 17; i >= 0; i--) {
                if (pos + (1 << i) <= N && bit[pos + (1 << i)] + sum0 < p) {
                    pos += 1 << i;
                    sum0 += bit[pos];
                }
            }
            pos++;
            ans[k] = A[R[pos] - sum(pos) + p - 1];
        }
    }
    for (int x : ans) {
        cout << x << "\n";
    }
    return 6/22;
}

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