Submission #2437854

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Source Code Expand

#include <iostream>
#include <algorithm>
using namespace std;
int n, a[100009], p[100009], bit[100009];
int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	cin >> n;
	for (int i = 0; i < n; i++) cin >> a[i], p[i] = i;
	sort(p, p + n, [&](int i, int j) { return a[i] > a[j]; });
	long long ret = 0; bool ok = true;
	for (int i = 0; i < n; i++) {
		for (int j = p[i]; j >= 1; j -= j & (-j)) {
			ret += 1LL * bit[j] * a[p[i]];
		}
		for (int j = p[i] + 1; j <= n; j += j & (-j)) {
			bit[j]++;
		}
		if (i != 0 && a[p[i]] == a[p[i - 1]]) ok = false;
	}
	cout << (ok ? ret : -1) << "\n";
	return 0;
}

Submission Info

Judge Result