Submission #871323

#	Time	Username	Problem	Language	Result	Execution time	Memory
871323		Trisanu_Das	Diversity (CEOI21_diversity)	C++17	64 / 100	77 ms	11060 KiB

diversity

#include<bits/stdc++.h>
#define int long long
using namespace std;

const int N = 3e5 + 5, mod = 1e9 + 7;
int t, n, a[300005], c[300005];

signed main(){
	int q;
	cin >> n >> q;
	for(int i = 1; i <= n; i++) cin >> a[i], c[a[i]]++;
	vector<int> x;
	for(int i = 1; i <= n; i++) {
		if(!c[a[i]]) continue;
		x.push_back(c[a[i]]);
		c[a[i]] = 0;
	}
	sort(x.rbegin(), x.rend());
	int t = 0;
	deque<int> dq;
	for(int i = 0; i < x.size(); i++) {
		if(t) dq.push_front(x[i]);
		else dq.push_back(x[i]);
		t ^= 1;
	}
	int p = 0, ans = x.size() * n * (n + 1) / 2;
	while(dq.size()) {
		int x = dq.front();
		dq.pop_front();
		ans -= (p * (p + 1) / 2);
		p += x;
		ans -= ((n - p) * (n - p + 1)) / 2;
	}
	cout << ans;
}

Compilation message (stderr)

diversity.cpp: In function 'int main()':
diversity.cpp:21:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  for(int i = 0; i < x.size(); i++) {
      |                 ~~^~~~~~~~~~

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