Submission #708772

#	Time	Username	Problem	Language	Result	Execution time	Memory
708772		becaido	Abracadabra (CEOI22_abracadabra)	C++17	100 / 100	549 ms	40472 KiB

Main

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout (T t, U...u) {cout << t << (sizeof... (u) ? ", " : ""), dout (u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

const int SIZE = 2e5 + 5;
const int QSIZ = 1e6 + 5;

int n, q;
int a[SIZE], p[SIZE], nxt[SIZE], cnt[SIZE];

int ans[QSIZ];
tuple<int, int, int> ask[QSIZ];

int bit[SIZE];
void upd(int pos, int x) {
    for (; pos <= n; pos += pos & -pos) bit[pos] += x;
}
int que(int pos) {
    int re = 0;
    for (; pos; pos -= pos & -pos) re += bit[pos];
    return re;
}
pair<int, int> sch(int x) {
    int pos = 0, sum = 0;
    for (int i = __lg(n); i >= 0; i--) if (pos + (1 << i) <= n && sum + bit[pos + (1 << i)] <= x) {
        sum += bit[pos += 1 << i];
    }
    return {pos + 1, sum};
}

bool work() {
    auto [k, sum] = sch(n / 2);
    if (sum == n / 2) return 0;
    int len = cnt[k] - (n / 2 - sum);
    upd(k, -len);
    cnt[k] -= len;
    for (int x = a[p[k] + (n / 2 - sum)]; x && !cnt[x]; x = nxt[x]) {
        cnt[x] = (nxt[x] && !cnt[nxt[x]] ? p[nxt[x]] - p[x] : len);
        len -= cnt[x];
        upd(x, cnt[x]);
    }
    return 1;
}

int cal(int i) {
    auto [k, sum] = sch(i - 1);
    return a[p[k] + (i - sum - 1)];
}

void solve() {
    cin >> n >> q;
    FOR (i, 1, n) cin >> a[i], p[a[i]] = i;
    FOR (i, 1, q) {
        auto &[t, k, id] = ask[i];
        cin >> t >> k;
        id = i;
    }
    sort(ask + 1, ask + q + 1);

    vector<int> st;
    for (int i = n; i >= 1; i--) {
        while (st.size() && a[i] > st.back()) st.pop_back();
        if (st.size()) nxt[a[i]] = st.back();
        st.pb(a[i]);
    }
    for (int x = a[1]; x; x = nxt[x]) {
        cnt[x] = (nxt[x] ? p[nxt[x]] : n + 1) - p[x];
        upd(x, cnt[x]);
    }

    int cur = 0, f = 1;
    FOR (i, 1, q) {
        auto &[t, k, id] = ask[i];
        while (f && cur < t) {
            cur++;
            f &= work();
        }
        ans[id] = cal(k);
    }
    FOR (i, 1, q) cout << ans[i] << '\n';
}

int main() {
    Waimai;
    solve();
}

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