Hackerearth Maximize the sum problem solution

#include<bits/stdc++.h>
using namespace std;
#define ll long long
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int t;
    cin >> t;
    while(t--)
    {
        int n, k;
        cin >> n >> k;
        multiset<ll> s;
        int i;
        vector<int> vec(n);
        for(i=0;i<n;i++)
            cin >> vec[i];
        sort(vec.begin(), vec.end());
        for(i=0;i<n;i++)
        {
            int j = i;
            while(j < n && vec[j] == vec[i])
                j++;
            s.insert((j - i)*1ll*vec[i]);
            i = j - 1;
        }
        ll sum = 0;
        int cnt = 0;
        while(s.size() && cnt < k)
        {
            ll ele = *s.rbegin();
            if(ele <= 0)
                break;
            sum+=ele;
            cnt++;
            s.erase(s.find(ele));
        }
        cout << sum << 'n';
    }
}