Kortit

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>

using namespace std;

int n, half;
vector<int> a;
set<int> s;
vector<int> b;

void f() {
  cin >> n;
  half = n/2;

  s.clear();
  a.clear();
  b.clear();
  a.resize(half);
  
  for (int i = 0; i < half; i++) {
    int x;
    cin >> x;
    s.insert(x);
    a[i] = x;
  }

  sort(a.rbegin(), a.rend());

  for (int i = n, ii = 0; i > 0; i--) {
    if (i == a[ii]) ii++;
    else (b.push_back(i));
  }

  int points = 0;
  for (int i = 0; i < half; i++) {
    auto it = s.upper_bound(b[i]);

    if (it != s.end()) {
      s.erase(it);
      points++;
    }
  }

  cout << points << "\n";
}

int t;
int main() {
  cin >> t;
  for (int i = 0; i < t; i++) f();
}

Test 1

Group: 1, 2

Verdict: WRONG ANSWER

Test 2

Group: 2

Verdict: WRONG ANSWER