WA E Максимизация цен

#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <string>
#include <stack>
#include <set>
#include <map>
#define pii pair <int,int>
#define vec vector
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
void cv(vector <int> &v){
    for (auto x: v) cout<<x<<' ';
    cout<<"\n";
}

void cvl(vector <ll> &v){
    for (auto x: v) cout<<x<<' ';
    cout<<"\n";
}


void cvv(vector <vector <int> > &v){
    for (auto x: v) cv(x);
    cout<<"\n";
}

void cvb(vector <bool> v){
    for (bool x: v) cout<<x<<' ';
    cout<<"\n";
}

void cvs(vector <string>  v){
    for (auto a: v){
        cout<<a<<"\n";
    }
}



int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t,n,k,ans=0;cin>>t;
    for (int go=0;go<t;++go){
        cin>>n>>k;
        vector <int> v(n);
        ans=0;
        for (int i = 0; i < n; ++i){
            int x; cin>>x;
            ans += x / k;
            v[i] = x%k;
        }
        //cout<<"k = "<<k<<"\n";
        //cout<<"ans= "<<ans<<"\n";
        //cout<<"v\n"; cv(v);
        sort(v.begin(), v.end());
        int a = 0, b = n - 1;
        while (b > a){

            if (v[a] + v[b] >= k){
                ans += (v[a] + v[b]) / k;
                a++;
                b--;
            }
            else{
                a++;
            }
        }
        //cout<<"ans = "<<ans<<"\n";
        cout<<ans<<"\n";
    }
}