Submission #708157

#	Time	Username	Problem	Language	Result	Execution time	Memory
708157		vjudge1	Diversity (CEOI21_diversity)	C++11	64 / 100	363 ms	17124 KiB

diversity

#include <bits/stdc++.h>

using namespace std;
using LL = long long;

int main() {
  ios::sync_with_stdio(false), cin.tie(0);
  int n, q;
  cin >> n >> q;
  vector<int> A(n);
  map<int, int> M;
  for (int &a : A) cin >> a, M[a] = 0;

  int k = 0;
  for (auto &p : M) p.second = k++;
  vector<LL> cnt(k);
  for (int &a : A) a = M[a], ++cnt[a];

  int L, R;
  cin >> L >> R;
  assert(q == 1 && L == 1 && R == n);

  LL ans = 0;
  sort(cnt.begin(), cnt.end());
  for (LL c : cnt) ans += c * (c + 1) / 2 + c * (n - c);
  LL l = 0, r = 0, gi = 1;
  // LL G[2], gi = 1;
  for (LL c : cnt) {
    // ans += G[gi] * (n - c - G[gi]), G[gi] += c;
    if (gi)
      ans += l * (n - c - l), l += c;
    else
      ans += r * (n - c - r), r += c;
    gi ^= 1;
  }
  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