Submission #698623

#	Time	Username	Problem	Language	Result	Execution time	Memory
698623		Cyanmond	Diversity (CEOI21_diversity)	C++17	64 / 100	7063 ms	23356 KiB

diversity

#include <bits/stdc++.h>

using i64 = long long;
constexpr i64 inf64 = 1ll << 60;

struct Query {
    int l;
    int r;
};

i64 calc(std::vector<int> X) {
    const int n = (int)X.size();
    std::vector<i64> lSum(n + 1), rSum(n + 1);
    for (int i = 0; i < n; ++i) {
        lSum[i + 1] = lSum[i] + X[i];
    }
    for (int i = n - 1; i >= 0; --i) {
        rSum[i] = rSum[i + 1] + X[i];
    }
    const auto s = lSum[n];
    auto p2 = [](i64 x) {
        return x * (x + 1) / 2;
    };
    i64 ans = 0;
    for (int i = 0; i < n; ++i) {
        ans += p2(s) - p2(lSum[i]) - p2(rSum[i + 1]);
    }
    return ans;
}

i64 naive(std::vector<int> A) {
    std::map<int, int> countS;
    for (const auto e : A) {
        ++countS[e];
    }
    A.clear();
    for (auto &[key, val] : countS) {
        A.push_back(val);
    }
    std::sort(A.begin(), A.end());
    std::vector<int> B(A.size());
    for (int i = 0; i < (int)A.size(); ++i) {
        if (i % 2 == 0) {
            B[i / 2] = A[i];
        } else {
            B[(int)A.size() - (i / 2) - 1] = A[i];
        }
    }
    return calc(B);
}

int main() {
    int N, Q;
    std::cin >> N >> Q;
    std::vector<int> A(N);
    for (auto &e : A) {
        std::cin >> e;
    }
    std::vector<Query> queries(Q);
    for (auto &[l, r] : queries) {
        std::cin >> l >> r;
        --l;
    }

    for (int i = 0; i < Q; ++i) {
        std::vector<int> vec;
        std::copy(A.begin() + queries[i].l, A.begin() + queries[i].r, std::back_inserter(vec));
        std::cout << naive(vec) << std::endl;
    }
}

• Subtask 1: 4 / 4
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 16 / 16
• Subtask 5: 26 / 26
• Subtask 6: 0 / 36