Kortit

#include <iostream>
#include <vector>
int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int t;
	std::cin >> t;
	while (t--) {
		int n;
		std::cin >> n;
		std::vector<int> v(n);
		for (int i = 0; i < n / 2; ++i) {
			int x;
			std::cin >> x;
			v[x - 1] = 1;
		}
		int s = 0, p = 0;
		for (int i = 0; i < n; ++i) {
			p += !v[i];
			if (v[i] && p) {
				s++;
				p--;
			}
		}
		std::cout << s << '\n';
	}
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED