Kortit

#include <bits/stdc++.h>
using namespace std;
 
void solve() {
	int n;
	cin>>n;
	set<int> my;
	set<int> has;
	for (int i=0;i<n/2;i++){
		int x;
		cin>>x;
		my.insert(x);
		has.insert(x);
	}
	int p=0;
	for (int i=n;i>=1;i--){
		if (my.count(i)) continue;
		int x = *has.rbegin();
		int y = *has.begin();
		if (x>i){
			p++;
			has.erase(x);
		} else {
			has.erase(y);
		}
	}
	cout<<p<<endl;
}
 
int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int tcs;
	cin>>tcs;
	for (int tc=1;tc<=tcs;tc++){
		solve();
	}
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED