Submission #592392

#	Time	Username	Problem	Language	Result	Execution time	Memory
592392		SeDunion	Diversity (CEOI21_diversity)	C++17	64 / 100	238 ms	20344 KiB

diversity

#include <iostream>
#include <cassert>
#include <iomanip>
#include <algorithm>
#include <string>
#include <bitset> 
#include <vector>
#include <cmath>
#include <deque>
#include <queue>
#include <stack>
#include <map>
#include <set>
#ifndef LOCAL
	#include <bits/stdc++.h>
	#define cerr if(false)cerr
#endif
 
using namespace std;
using ll = long long;
 
const int N = 1e6 + 66;
 
ll a[N], n;
 
ll pref[N];

/*
summa(a[i]*(a[i]+1)/2 + a[i]*pref[i-1]*(i+1) - a[i]*(pref[n-1]-pref[i])*i)
summa((a[i]^2+a[i])/2 + a[i]*pref[i-1]*i+a[i]*pref[i-1] - a[i]*(pref[n-1]-pref[i])*i)
summa((a[i]^2+a[i])/2 + a[i]*pref[i]*i-a[i]^2*i + a[i]*pref[i-1] - a[i]*(pref[n-1]-pref[i])*i)
summa((a[i]^2+a[i])/2 + a[i]*pref[i]*i-a[i]^2*i + a[i]*pref[i]-a[i]^2 - a[i]*(pref[n-1]-pref[i])*i)
summa((a[i]^2+a[i])/2 + a[i]*pref[i]*i-a[i]^2*i + a[i]*pref[i]-a[i]^2 - a[i]*pref[n-1]*i - a[i]*pref[i]*i)
summa((a[i]^2+a[i])/2 + a[i]*pref[i]*i - a[i]^2*i + a[i]*pref[i]-a[i]^2 - a[i]*pref[n-1]*i - a[i]*pref[i]*i)
summa(a[i]/2 + a[i]*pref[i]*(i+1) - a[i]^2*i - a[i]^2/2 - a[i]*pref[n-1]*i - a[i]*pref[i]*i)
summa(a[i]/2 + a[i]*pref[i] - a[i]^2*i - a[i]^2/2 - a[i]*pref[n-1]*i)
summa(a[i]/2 + a[i]*pref[i] - a[i]^2*i - a[i]^2/2 - a[i]*pref[n-1]*i)
 */

ll f(ll s) { return s * (s + 1) / 2; }

ll solve() {
	ll ans = 0;
	for (int i = 0 ; i < n ; ++ i) {
		pref[i] = a[i];
		if (i) pref[i] += pref[i - 1];
	}
	for (int i = 0 ; i < n ; ++ i) {
		if (i) ans += f(pref[i - 1]);
		ans += f(pref[n - 1] - pref[i]);
	}
	ll C = n * f(pref[n-1]);
	return C-ans;
}
 
int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int q;
	cin >> n >> q;
	for (int i = 0 ; i < n ; ++ i) cin >> a[i];
	cin >> q >> q;
	map<int,int>mp;
	for (int i = 0 ; i < n ; ++ i) mp[a[i]]++;
	vector<int>freq;
	for (auto [f, s] : mp) freq.emplace_back(s);
	sort(freq.rbegin(), freq.rend());
	deque<int>p;
	for (int i : freq) {
		if ((int)p.size() & 1) p.push_back(i);
		else p.push_front(i);
	}
	n = p.size();
	for (int i = 0 ; i < n ; ++ i) a[i] = p[i];
	cout << solve();
}

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