Submission #1003944

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003944		vjudge1	Ekoeko (COCI21_ekoeko)	C++17	110 / 110	16 ms	3356 KiB

Main

#include <bits/stdc++.h>

using namespace std;
using lli = long long;

const int MAXN = 2e5 + 10;

int bit[MAXN];

void add(int idx, int x, int n) {
	for (; idx < n; idx = idx | (idx + 1))
		bit[idx] += x;
}

int pref(int idx) {
	int sum = 0;
	for (; idx >= 0; idx = (idx & (idx + 1)) - 1)
		sum += bit[idx];

	return sum;
}

int sum(int l, int r) { return pref(r) - pref(l-1); }

int main() {
	int n;
	cin >> n;

	n *= 2;

	string s;
	cin >> s;

	vector<vector<int>> cnt(26);
	for (int i = 0; i < n; ++i)
		cnt[s[i] - 'a'].push_back(i);

	vector<int> perm(n);
	int atual = 0; string final;
	vector<int> cnt2(26);
	for (int i = 0; i < n; ++i) {
		int c = s[i] - 'a';
		if (cnt2[c] < cnt[c].size()/2) {
			++cnt2[c];
			perm[i] = atual++;
			final.push_back(s[i]);
		}
	}

	for (char c: final)
		perm[cnt[c - 'a'][cnt2[c - 'a']++]] = atual++;

	lli ans = 0;
	for (int i = 0; i < n; ++i) {
		ans += sum(perm[i], n);
		add(perm[i], 1, n);
	}

	cout << ans << "\n";
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:43:15: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |   if (cnt2[c] < cnt[c].size()/2) {

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 20 / 20
• Subtask 5: 40 / 40