Submission #956734

#	Time	Username	Problem	Language	Result	Execution time	Memory
956734		TAhmed33	Diversity (CEOI21_diversity)	C++17	64 / 100	731 ms	13136 KiB

diversity

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 3e5 + 1;
const int B = 500;
int a[MAXN], n, q;
array <int, 3> queries[MAXN];
ll ans[MAXN];
int freq[MAXN], freq2[MAXN];
set <int> t;
void add (int x) {
	if (freq2[freq[a[x]]] == 1) t.erase(freq[a[x]]);
	freq2[freq[a[x]]]--;
	freq[a[x]]++;
	freq2[freq[a[x]]]++;
	if (freq2[freq[a[x]]] == 1) t.insert(freq[a[x]]);
}
void rem (int x) {
	if (freq2[freq[a[x]]] == 1) t.erase(freq[a[x]]);
	freq2[freq[a[x]]]--;
	freq[a[x]]--;
	freq2[freq[a[x]]]++;
	if (freq2[freq[a[x]]] == 1) t.insert(freq[a[x]]);
}
int main () {
	ios::sync_with_stdio(0); cin.tie(0);
	cin >> n >> q;
	freq2[0] = MAXN; t.insert(0); 
	for (int i = 1; i <= n; i++) cin >> a[i];
	for (int i = 1; i <= q; i++) {
		int l, r; cin >> l >> r;
		queries[i] = {l, r, i};
	}
	sort(queries + 1, queries + q + 1, [&] (array <int, 3> &x, array <int, 3> &y) {
		return x[0] / B == y[0] / B ? x[1] < y[1] : x[0]  / B < y[0] / B;
	});
	int L = queries[1][0] + 1, R = queries[1][0];
	for (int i = 1; i <= q; i++) {
		while (L > queries[i][0]) add(--L);
		while (L < queries[i][0]) rem(L++);
		while (R > queries[i][1]) rem(R--);
		while (R < queries[i][1]) add(++R);
		ll dis = 0; ll n = R - L + 1;
		vector <pair <ll, ll>> pp[2];
		int c = 0;
		for (auto j : t) {
			if (!j) continue;
			dis += freq2[j];
			int x = j, y = freq2[j];
			if (y == 1) {
				pp[c].push_back({x, 1});
				c ^= 1; 
			} else {
				int l = (y + 1) / 2, r = y / 2;
				pp[c].push_back({x, l});
				pp[c ^ 1].push_back({x, r});
				c ^= (y & 1);
			}
		}
		reverse(pp[1].begin(), pp[1].end());
		for (auto j : pp[1]) pp[0].push_back(j);
		ll cur = 0, pref = 0;
		for (auto [x, y] : pp[0]) {
			cur += pref * pref * y + y * (y - 1) / 2 * 2 * pref * x + x * x * (y - 1) * y * (2 * y - 1) / 6 + y * pref + x * y * (y - 1) / 2;
			cur += y * n * n - y * n * pref - n * y * (y + 1) / 2 * x + y * n;
			cur += -y * n * pref + pref * pref * y + pref * y * (y + 1) / 2 * x - y * pref;
			cur += -n * y * (y + 1) / 2 * x + y * (y + 1) / 2 * x * pref + x * x * y * (y + 1) * (2 * y + 1) / 6 - y * (y + 1) / 2 * x;
			pref += x * y;
		}	
		ans[queries[i][2]] = n * (n + 1) / 2 * dis - cur / 2;
	}
	for (int i = 1; i <= q; i++) cout << ans[i] << '\n';
}

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