Submission #1114594

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114594		vjudge1	Diversity (CEOI21_diversity)	C++17	64 / 100	41 ms	14408 KiB

diversity

#include <bits/stdc++.h>

using i64 = long long;

#ifdef DEBUG 
    #include "/home/ahmetalp/Desktop/Workplace/debug.h"
#else
    #define debug(...) void(23)
#endif

constexpr int max_A = int(3E5) + 5;

int cnt[max_A];

i64 calc_slow(std::vector<i64> x) {
    int n = int(x.size());
    i64 ans = 0;
    for (int i = 0; i < n; ++i) {
        ans += x[i] * (x[i] + 1) / 2;
        i64 s = 0;
        for (int j = i + 1; j < n; ++j) {
            s += x[j] * (j - i + 1);
        }
        debug(i, s);
        ans += x[i] * s;
    }
    return ans;
}

i64 calc(std::vector<i64> x) {
    int n = int(x.size());
    i64 ans = 0;
    std::vector<i64> sum(n + 1), f(n + 1);
    for (int i = n - 1; i >= 0; --i) {
        sum[i] = sum[i + 1] + x[i];
    }
    for (int i = n - 1; i >= 0; --i) {
        f[i] = f[i + 1] + sum[i];
    }
    debug(sum, f);
    for (int i = 0; i < n; ++i) {
        ans += x[i] * (x[i] + 1) / 2;
        debug(i, f[i + 1] + sum[i + 1]);
        ans += x[i] * (f[i + 1] + sum[i + 1]);
    }
    return ans;
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int N, Q;
    std::cin >> N >> Q;
    std::vector<int> A(N);
    for (int i = 0; i < N; ++i) {
        std::cin >> A[i];
    }

    std::vector<int> L(Q), R(Q);
    for (int i = 0; i < Q; ++i) {
        std::cin >> L[i] >> R[i];
    }

    for (int i = 0; i < N; ++i) {
        ++cnt[A[i]];
    }

    std::vector<i64> x;
    for (int i = 0; i < max_A; ++i) {
        if (cnt[i] != 0) {
            x.emplace_back(cnt[i]);
        }
    }

    int n = int(x.size());

    std::sort(x.begin(), x.end());

    std::vector<i64> w(n);
    int l = 0, r = n - 1;
    for (int i = 0; i < n; ++i) {
        if (~i & 1) w[l++] = x[i];
        else w[r--] = x[i];
    }

    debug(w);

    i64 ans = calc(w);
    debug(calc_slow(w));
    std::cout << ans << '\n';

    return 0;
}

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