#include <bits/stdc++.h>   using namespace std;   long long solve() {     long long n, i, j, k;     cin >> n >> k;     long long arr[n];     for (i = 0; i < n; i++) cin >> arr[i];     sort(arr, arr + n);     j = 0;     for (i = 0; i < n && arr[i] < 0; i += k) j += 2 * abs(arr[i]);     for (i = n - 1; i >= 0 && arr[i] > 0; i -= k) j += 2 * arr[i];     j -= max(abs(arr[0]), abs(arr[n - 1]));     return j;   }   int main() {     long long t;     cin >> t;     while (t--) cout << solve() << endl;     return 0;   }   