X Wrong Answer

i am a newbie to codechef and i daily use it but the thing is that when i have an solution which has the correct answers for the test case and still does not gets accepted , please help me with this thing. Like the problem “CFRTEST” my submission id is “77197095”.
i need a serious help with this thing please help me out my dear experts…

The main idea in this question is to count the days only once.

Let’s take an example of 1 1 2 3 4 5 6 7 7 8 9. The first and second friends want a party on day 1 but Devu can only give party to any one friend on a single day. Hence he will only give party to the first friend. By this logic, the answer for the above question is 9 i.e. 1 2 3 4 5 6 7 8 9.

You can use a set and store the days "di" in it. Then just return the size of the set.

#include <iostream>
#include <set>
using namespace std;

int main() {
	// your code goes here
	int t;
	cin >> t;
	while (t--) {
	    int n;
	    cin >> n;
	    set<int, greater<int> > D;
	    while (n--) {
	        int d;
	        cin >> d;
	    cout << D.size() << "\n";
	return 0;