Submission #968672

#	Time	Username	Problem	Language	Result	Execution time	Memory
968672		RandomUser	Index (COCI21_index)	C++17	110 / 110	583 ms	154688 KiB

index

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;

struct BIT {
    int n;
    vector<int> tree;

    void config(int _n) {
        n = _n + 10;
        tree.resize(_n+60);
    }

    void update(int p, int v) {
        for(p++; p<n; p+=p&-p) tree[p] += v;
    }

    int query(int p) {
        int ans = 0;
        for(p++; p>0; p-=p&-p) ans += tree[p];
        return ans;
    }

    int query(int l, int r) { return query(r) - query(l-1); }
    void reset() { for(int &x : tree) x = 0; }
};

stack<int> to_change[200005];
vector<int> v[200005];

int32_t main() {
    ios_base::sync_with_stdio(false);
    cout.tie(0); cin.tie(0);

    int n, q;
    cin >> n >> q;

    vector<int> L(q), R(q, 2e5), ANS(q, 1);

    for(int i=1; i<=n; i++) {
        int x;
        cin >> x;
        v[x].push_back(i);
    }

    vector<pii> qus(q);
    for(pii &x : qus) cin >> x.first >> x.second;

    bool changed = 1;
    BIT bit; bit.config(2e5);
    while(changed) {
        changed = 0;

        for(int i=0; i<q; i++)
            if(L[i] <= R[i]) to_change[(L[i] + R[i]) / 2].push(i);

        for(int i=2e5; i>=1; i--) {
            for(int &x : v[i]) bit.update(x, 1);
            while(!to_change[i].empty()) {
                changed = 1;
                int id = to_change[i].top();
                to_change[i].pop();
                if(bit.query(qus[id].first, qus[id].second) >= i) ANS[id] = i, L[id] = i + 1;
                else R[id] = i - 1;
            }
        }

        bit.reset();
    }

    for(int &x : ANS) cout << x << '\n';
    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 50 / 50