Codeforces Round #797 (Div. 3) (E. Price Maximization)

Bismillahir Rahmanir Rahim

///Author: Tanvir Ahmmad

///CSE,Islamic University,Bangladesh

#include<iostream>

#include<cstdio>

#include<algorithm>

#include<string>

#include<cstring>

#include<sstream>

#include<cmath>

#include<cstring>

#include<vector>

#include<queue>

#include<map>

#include<set>

#include<stack>

#include<vector>

#include<iterator>

#include <functional> ///sort(arr,arr+n,greater<int>()) for decrement of array

/*every external angle sum=360 degree

  angle find using polygon hand(n) ((n-2)*180)/n*/

///Floor[Log(b)  N] + 1 = the number of digits when any number is represented in base b

using namespace std;

typedef long long ll;

int main()

{

    ll tst,n,k;

    cin>>tst;

    while(tst--)

    {

        vector<ll>vec;

        cin>>n>>k;

        ll arr[n+7],sum=0;

        for(ll i=1;i<=n;i++)

        {

            cin>>arr[i],sum+=(arr[i]/k);

            if((arr[i]%k)!=0) vec.push_back(arr[i]%k);

        }

        sort(vec.begin(),vec.end());

        ll pos=vec.size()-1;

        for(ll i=0;i<vec.size() && i<pos;i++)

            if(vec[i]+vec[pos]>=k) sum++,pos--;

        cout<<sum<<endl;

    }

    return 0;

}

Problem Link: https://codeforces.com/contest/1690/problem/E