Submission #964792

#	Time	Username	Problem	Language	Result	Execution time	Memory
964792		Pekiban	Index (COCI21_index)	C++17	110 / 110	235 ms	22684 KiB

index

#include <bits/stdc++.h>

using namespace std;

const int mxN = 2e5+2;
int L[mxN], R[mxN], ans[mxN], bit[mxN], c = mxN - 1;
vector<int> d[mxN];
void add(int idx, int x) {
    while (idx < mxN) {
        bit[idx] += x;
        idx |= (idx + 1);
    }
}
int sum(int idx) {
    int s = 0;
    while (idx >= 0) {
        s += bit[idx];
        idx &= (idx + 1);
        --idx;
    }
    return s;
}
int sum(int l, int r) {
    return l ? sum(r) - sum(l-1) : sum(r);
}
void pbs(int l, int r, vector<int> &b) {
    if (r < l || b.empty()) return;
    if (l == r) {
        for (auto u : b) {
            ans[u] = l;
        }
        return;
    }
    int mid = (l + r)/2;
    while (c > mid-1) {
        for (auto u : d[c]) {
            add(u, 1);
        }
        --c;
    }
    while (c < mid-1) {
        ++c;
        for (auto u : d[c]) {
            add(u, -1);
        }
    }
    vector<int> le, ri;
    for (auto x : b) {
        if (sum(L[x], R[x]) >= mid) {
            ri.push_back(x);
        }
        else {
            le.push_back(x);
        }
    }
    b.clear();
    pbs(l, mid, le);
    pbs(mid+1, r, ri);
}
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n, q;
    cin >> n >> q;
    for (int i = 0; i < n; ++i) {
        int x;
        cin >> x;
        d[x].push_back(i);
    }
    vector<int> b;
    for (int i = 0; i < q; ++i) {
        cin >> L[i] >> R[i];
        --L[i], --R[i];
        b.push_back(i);
    }
    pbs(0, n+1, b);
    for (int i = 0; i < q; ++i) {
        cout << ans[i]-1 << '\n';
    }
}

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