description: A total of n depots are located on a number line. Depot i lies at the point x_i for 1 ≤ i ≤ n.
  
  You are a salesman with n bags of goods, attempting to deliver one bag to each of the n depots. You and the n bags are initially at the origin 0. You can carry up to k bags at a time. You must collect the required number of goods from the origin, deliver them to the respective depots, and then return to the origin to collect your next batch of goods.
  
  Calculate the minimum distance you need to cover to deliver all the bags of goods to the depots. You do not have to return to the origin after you have delivered all the bags.
  
  Input
  
  Each test contains multiple test cases. The first line contains the number of test cases t (1 ≤ t ≤ 10 500). Description of the test cases follows.
  
  The first line of each test case contains two integers n and k (1 ≤ k ≤ n ≤ 2 ⋅ 10^5).
  
  The second line of each test case contains n integers x_1, x_2, …, x_n (-10^9 ≤ x_i ≤ 10^9). It is possible that some depots share the same position.
  
  It is guaranteed that the sum of n over all test cases does not exceed 2 ⋅ 10^5.
  
  Output
  
  For each test case, output a single integer denoting the minimum distance you need to cover to deliver all the bags of goods to the depots. 
  
  Example
  
  Input
  
  
  4
  5 1
  1 2 3 4 5
  9 3
  -5 -10 -15 6 5 8 3 7 4
  5 3
  2 2 3 3 3
  4 2
  1000000000 1000000000 1000000000 1000000000
  
  
  Output
  
  
  25
  41
  7
  3000000000
  
  Note
  
  In the first test case, you can carry only one bag at a time. Thus, the following is a solution sequence that gives a minimum travel distance: 0 → 2 → 0 → 4 → 0 → 3 → 0 → 1 → 0 → 5, where each 0 means you go the origin and grab one bag, and each positive integer means you deliver the bag to a depot at this coordinate, giving a total distance of 25 units. It must be noted that there are other sequences that give the same distance.
  
  In the second test case, you can follow the following sequence, among multiple such sequences, to travel minimum distance: 0 → 6 → 8 → 7 → 0 → 5 → 4 → 3 → 0 → (-5) → (-10) → (-15), with distance 41. It can be shown that 41 is the optimal distance for this test case.
solution: import java.io.*;
  import java.util.*;
  
  import static java.lang.Math.*;
  import static java.lang.Math.ceil;
  import static java.util.Arrays.*;
  
  public class Codeforces {
      static int mod = 1000000007;
      static int ar[] = new int[10];
  
      public static void main(String[] args) throws IOException {
          int t = ri();
          while (t-- > 0) {
              int n = rni();
              int k = ni();
              long a[] = rla(n);
              List<Long> pos  = new ArrayList<>() , neg = new ArrayList<>();
              for (long l : a){
                  if(l < 0){
                      neg.add(-l);
                  }else{
                      pos.add(l);
                  }
              }
              pos.sort((x,y) -> Long.compare(y,x));
              neg.sort((x,y) -> Long.compare(y,x));
              long negBack = 0 , negEnd = 0  , posEnd = 0 , posBack = 0;
              int nsize = neg.size() , psize = pos.size();
              for (int i = 0 ; i < nsize ; i++){
                  if (i == 0){
                      negEnd+=neg.get(i);
                      negBack+=(neg.get(i)*2);
                  }else if (i%k == 0){
                      negEnd+=(neg.get(i)*2);
                      negBack+=(neg.get(i)*2);
                  }
              }
              for (int i = 0 ; i < psize ; i++){
                  if (i == 0){
                      posEnd+=pos.get(i);
                      posBack+=(pos.get(i)*2);
                  }else if (i%k == 0){
                      posEnd+=(pos.get(i)*2);
                      posBack+=(pos.get(i)*2);
                  }
              }
              prln(Math.min(posBack+negEnd,posEnd+negBack));
          }
          close();
      }
  
      static boolean check(int a, int b, int h, int m) {
          if (ar[a % 10] == -1 || ar[a / 10] == -1 || ar[b % 10] == -1 || ar[b / 10] == -1) {
              return false;
          }
          int x = ar[b % 10] * 10 + ar[b / 10];
          int y = ar[a % 10] * 10 + ar[a / 10];
          if (x < h && y < m) {
              return true;
          }
          return false;
      }
  
      static boolean isPalindrome(char[] c) {
          int low = 0, high = c.length - 1;
          while (low < high) {
              if (c[low] != c[high] || c[low] == '?' || c[high] == '?') return false;
              low++;
              high--;
          }
          return true;
      }
  
  
      static char get(int a) {
          return (char) (a + 'a');
      }
  
      static void addToPq(int n, PriorityQueue<Integer> p) {
          for (int i = 0; i < n; i++) {
              p.add(i);
          }
      }
  
      static boolean better(int a, int b, int[][] matrix) {
          int cnt = 0;
          for (int i = 0; i < 5; i++) {
              if (matrix[a][i] < matrix[b][i]) cnt++;
          }
          return cnt >= 3;
      }
  
      static BufferedReader __i = new BufferedReader(new InputStreamReader(System.in));
      static PrintWriter __o = new PrintWriter(new OutputStreamWriter(System.out));
      static StringTokenizer input;
      static Random __r = new Random();
  
      // references
      // IBIG = 1e9 + 7
      // IMAX ~= 2e9
      // LMAX ~= 9e18
  
      // constants
      static final int IBIG = 1000000007;
      static final int IMAX = 2147483647;
      static final long LMAX = 9223372036854775807L;
  
      // math util
      static int minof(int a, int b, int c) {
          return min(a, min(b, c));
      }
  
      static int minof(int... x) {
          if (x.length == 1) return x[0];
          if (x.length == 2) return min(x[0], x[1]);
          if (x.length == 3) return min(x[0], min(x[1], x[2]));
          int min = x[0];
          for (int i = 1; i < x.length; ++i) if (x[i] < min) min = x[i];
          return min;
      }
  
      static long minof(long a, long b, long c) {
          return min(a, min(b, c));
      }
  
      static long minof(long... x) {
          if (x.length == 1) return x[0];
          if (x.length == 2) return min(x[0], x[1]);
          if (x.length == 3) return min(x[0], min(x[1], x[2]));
          long min = x[0];
          for (int i = 1; i < x.length; ++i) if (x[i] < min) min = x[i];
          return min;
      }
  
      static int maxof(int a, int b, int c) {
          return max(a, max(b, c));
      }
  
      static int maxof(int... x) {
          if (x.length == 1) return x[0];
          if (x.length == 2) return max(x[0], x[1]);
          if (x.length == 3) return max(x[0], max(x[1], x[2]));
          int max = x[0];
          for (int i = 1; i < x.length; ++i) if (x[i] > max) max = x[i];
          return max;
      }
  
      static long maxof(long a, long b, long c) {
          return max(a, max(b, c));
      }
  
      static long maxof(long... x) {
          if (x.length == 1) return x[0];
          if (x.length == 2) return max(x[0], x[1]);
          if (x.length == 3) return max(x[0], max(x[1], x[2]));
          long max = x[0];
          for (int i = 1; i < x.length; ++i) if (x[i] > max) max = x[i];
          return max;
      }
  
      static int powi(int a, int b) {
          if (a == 0) return 0;
          int ans = 1;
          while (b > 0) {
              if ((b & 1) > 0) ans *= a;
              a *= a;
              b >>= 1;
          }
          return ans;
      }
  
      static long powl(long a, int b) {
          if (a == 0) return 0;
          long ans = 1;
          while (b > 0) {
              if ((b & 1) > 0) ans *= a;
              a *= a;
              b >>= 1;
          }
          return ans;
      }
  
      static int fli(double d) {
          return (int) d;
      }
  
      static int cei(double d) {
          return (int) ceil(d);
      }
  
      static long fll(double d) {
          return (long) d;
      }
  
      static long cel(double d) {
          return (long) ceil(d);
      }
  
      static int gcd(int a, int b) {
          return b == 0 ? a : gcd(b, a % b);
      }
  
      static long gcd(long a, long b) {
          return b == 0 ? a : gcd(b, a % b);
      }
  
      static int[] exgcd(int a, int b) {
          if (b == 0) return new int[]{1, 0};
          int[] y = exgcd(b, a % b);
          return new int[]{y[1], y[0] - y[1] * (a / b)};
      }
  
      static long[] exgcd(long a, long b) {
          if (b == 0) return new long[]{1, 0};
          long[] y = exgcd(b, a % b);
          return new long[]{y[1], y[0] - y[1] * (a / b)};
      }
  
      static int randInt(int min, int max) {
          return __r.nextInt(max - min + 1) + min;
      }
  
      static long mix(long x) {
          x += 0x9e3779b97f4a7c15L;
          x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9L;
          x = (x ^ (x >> 27)) * 0x94d049bb133111ebL;
          return x ^ (x >> 31);
      }
  
      public static boolean[] findPrimes(int limit) {
          assert limit >= 2;
  
          final boolean[] nonPrimes = new boolean[limit];
          nonPrimes[0] = true;
          nonPrimes[1] = true;
  
          int sqrt = (int) Math.sqrt(limit);
          for (int i = 2; i <= sqrt; i++) {
              if (nonPrimes[i]) continue;
              for (int j = i; j < limit; j += i) {
                  if (!nonPrimes[j] && i != j) nonPrimes[j] = true;
              }
          }
  
          return nonPrimes;
      }
  
      // array util
      static void reverse(int[] a) {
          for (int i = 0, n = a.length, half = n / 2; i < half; ++i) {
              int swap = a[i];
              a[i] = a[n - i - 1];
              a[n - i - 1] = swap;
          }
      }
  
      static void reverse(long[] a) {
          for (int i = 0, n = a.length, half = n / 2; i < half; ++i) {
              long swap = a[i];
              a[i] = a[n - i - 1];
              a[n - i - 1] = swap;
          }
      }
  
      static void reverse(double[] a) {
          for (int i = 0, n = a.length, half = n / 2; i < half; ++i) {
              double swap = a[i];
              a[i] = a[n - i - 1];
              a[n - i - 1] = swap;
          }
      }
  
      static void reverse(char[] a) {
          for (int i = 0, n = a.length, half = n / 2; i < half; ++i) {
              char swap = a[i];
              a[i] = a[n - i - 1];
              a[n - i - 1] = swap;
          }
      }
  
      static void shuffle(int[] a) {
          int n = a.length - 1;
          for (int i = 0; i < n; ++i) {
              int ind = randInt(i, n);
              int swap = a[i];
              a[i] = a[ind];
              a[ind] = swap;
          }
      }
  
      static void shuffle(long[] a) {
          int n = a.length - 1;
          for (int i = 0; i < n; ++i) {
              int ind = randInt(i, n);
              long swap = a[i];
              a[i] = a[ind];
              a[ind] = swap;
          }
      }
  
      static void shuffle(double[] a) {
          int n = a.length - 1;
          for (int i = 0; i < n; ++i) {
              int ind = randInt(i, n);
              double swap = a[i];
              a[i] = a[ind];
              a[ind] = swap;
          }
      }
  
      static void rsort(int[] a) {
          shuffle(a);
          sort(a);
      }
  
      static void rsort(long[] a) {
          shuffle(a);
          sort(a);
      }
  
      static void rsort(double[] a) {
          shuffle(a);
          sort(a);
      }
  
      static int[] copy(int[] a) {
          int[] ans = new int[a.length];
          for (int i = 0; i < a.length; ++i) ans[i] = a[i];
          return ans;
      }
  
      static long[] copy(long[] a) {
          long[] ans = new long[a.length];
          for (int i = 0; i < a.length; ++i) ans[i] = a[i];
          return ans;
      }
  
      static double[] copy(double[] a) {
          double[] ans = new double[a.length];
          for (int i = 0; i < a.length; ++i) ans[i] = a[i];
          return ans;
      }
  
      static char[] copy(char[] a) {
          char[] ans = new char[a.length];
          for (int i = 0; i < a.length; ++i) ans[i] = a[i];
          return ans;
      }
  
      static void resetBoolean(boolean[] vis, int n) {
          for (int i = 0; i < n; i++) {
              vis[i] = false;
          }
      }
  
      static void setMinusOne(int[][] matrix) {
          int row = matrix.length;
          int col = matrix[0].length;
  
          for (int i = 0; i < row; i++) {
              for (int j = 0; j < col; j++) {
                  matrix[i][j] = -1;
              }
          }
  
      }
  
      // input
      static void r() throws IOException {
          input = new StringTokenizer(rline());
      }
  
      static int ri() throws IOException {
          return Integer.parseInt(rline().split(" ")[0]);
      }
  
      static long rl() throws IOException {
          return Long.parseLong(rline());
      }
  
      static double rd() throws IOException {
          return Double.parseDouble(rline());
      }
  
      static int[] ria(int n) throws IOException {
          int[] a = new int[n];
          r();
          for (int i = 0; i < n; ++i) a[i] = ni();
          return a;
      }
  
      static void ria(int[] a) throws IOException {
          int n = a.length;
          r();
          for (int i = 0; i < n; ++i) a[i] = ni();
      }
  
      static int[] riam1(int n) throws IOException {
          int[] a = new int[n];
          r();
          for (int i = 0; i < n; ++i) a[i] = ni() - 1;
          return a;
      }
  
      static void riam1(int[] a) throws IOException {
          int n = a.length;
          r();
          for (int i = 0; i < n; ++i) a[i] = ni() - 1;
      }
  
      static long[] rla(int n) throws IOException {
          long[] a = new long[n];
          r();
          for (int i = 0; i < n; ++i) a[i] = nl();
          return a;
      }
  
      static void rla(long[] a) throws IOException {
          int n = a.length;
          r();
          for (int i = 0; i < n; ++i) a[i] = nl();
      }
  
      static double[] rda(int n) throws IOException {
          double[] a = new double[n];
          r();
          for (int i = 0; i < n; ++i) a[i] = nd();
          return a;
      }
  
      static void rda(double[] a) throws IOException {
          int n = a.length;
          r();
          for (int i = 0; i < n; ++i) a[i] = nd();
      }
  
      static char[] rcha() throws IOException {
          return rline().toCharArray();
      }
  
      static void rcha(char[] a) throws IOException {
          int n = a.length, i = 0;
          for (char c : rline().toCharArray()) a[i++] = c;
      }
  
      static String rline() throws IOException {
          return __i.readLine();
      }
  
      static String n() {
          return input.nextToken();
      }
  
      static int rni() throws IOException {
          r();
          return ni();
      }
  
      static int ni() {
          return Integer.parseInt(n());
      }
  
      static long rnl() throws IOException {
          r();
          return nl();
      }
  
      static long nl() {
          return Long.parseLong(n());
      }
  
      static double rnd() throws IOException {
          r();
          return nd();
      }
  
      static double nd() {
          return Double.parseDouble(n());
      }
  
      // output
      static void pr(int i) {
          __o.print(i);
      }
  
      static void prln(int i) {
          __o.println(i);
      }
  
      static void pr(long l) {
          __o.print(l);
      }
  
      static void prln(long l) {
          __o.println(l);
      }
  
      static void pr(double d) {
          __o.print(d);
      }
  
      static void prln(double d) {
          __o.println(d);
      }
  
      static void pr(char c) {
          __o.print(c);
      }
  
      static void prln(char c) {
          __o.println(c);
      }
  
      static void pr(char[] s) {
          __o.print(new String(s));
      }
  
      static void prln(char[] s) {
          __o.println(new String(s));
      }
  
      static void pr(String s) {
          __o.print(s);
      }
  
      static void prln(String s) {
          __o.println(s);
      }
  
      static void pr(Object o) {
          __o.print(o);
      }
  
      static void prln(Object o) {
          __o.println(o);
      }
  
      static void prln() {
          __o.println();
      }
  
      static void pryes() {
          prln("yes");
      }
  
      static void pry() {
          prln("Yes");
      }
  
      static void prY() {
          prln("YES");
      }
  
      static void prno() {
          prln("no");
      }
  
      static void prn() {
          prln("No");
      }
  
      static void prN() {
          prln("NO");
      }
  
      static boolean pryesno(boolean b) {
          prln(b ? "yes" : "no");
          return b;
      }
  
      ;
  
      static boolean pryn(boolean b) {
          prln(b ? "Yes" : "No");
          return b;
      }
  
      static boolean prYN(boolean b) {
          prln(b ? "YES" : "NO");
          return b;
      }
  
      static void prln(int... a) {
          for (int i = 0, len = a.length - 1; i < len; pr(a[i]), pr(' '), ++i) ;
          if (a.length > 0) prln(a[a.length - 1]);
          else prln();
      }
  
      static void prln(long... a) {
          for (int i = 0, len = a.length - 1; i < len; pr(a[i]), pr(' '), ++i) ;
          if (a.length > 0) prln(a[a.length - 1]);
          else prln();
      }
  
      static void prln(double... a) {
          for (int i = 0, len = a.length - 1; i < len; pr(a[i]), pr(' '), ++i) ;
          if (a.length > 0) prln(a[a.length - 1]);
          else prln();
      }
  
      static <T> void prln(Collection<T> c) {
          int n = c.size() - 1;
          Iterator<T> iter = c.iterator();
          for (int i = 0; i < n; pr(iter.next()), pr(' '), ++i) ;
          if (n >= 0) prln(iter.next());
          else prln();
      }
  
      static void h() {
          prln("hlfd");
          flush();
      }
  
      static void flush() {
          __o.flush();
      }
  
      static void close() {
          __o.close();
      }
  
  }
  