Help me in solving LARGESTK problem

help
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1

My issue

First, I used a set to count the unique elements in the array. Then, I calculated the number of remaining elements, which are duplicates, and stored that in a variable. Since the set contains all distinct elements and is a subsequence of the original array, the minimum value of K would be the size of the set. Given that the number of distinct elements is fixed, adding more elements will not increase the distinct count. Therefore, I counted how many times I could add these extra elements to increase the size of the subsequence K.
I am unable to find out why my code is not working correctly? Please help me.

My code

#include <bits/stdc++.h>
#define lp(n) for(int i=0; i<n; i++)
#define ll long long
#define endl '\n'
#define sza(x) ((int)x.size())
#define aint(a) (a).begin(), (a).end()
#define FAST_IO ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
using namespace std;

int main() {
    FAST_IO;
    int t;
    cin >>t;
    
    while(t--){
        int n;
        cin >> n;
        set<int> s; // unique elements
        int dup; // no of duplicate elements
        lp(n){
            int a;
            cin >> a;
            s.insert(a);
        }
        int K = s.size(); // since the set consits of k distinct element and it's size is k
        dup = n-K;
        K += K*(dup/K);
        cout << K << endl;
        
    }
}

Problem Link: Largest K Practice Coding Problem