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.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.lang.reflect.Array;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.*;
  
  public class Main {
      public static void main(String[] args){
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          solve(in, out);
          out.close();
      }
  
      static String reverse(String s) {
          return (new StringBuilder(s)).reverse().toString();
      }
  
      static void sieveOfEratosthenes(int n, int factors[], ArrayList<Integer> ar) 
      { 
          factors[1]=1;
          int p;
          for(p = 2; p*p <=n; p++) 
          { 
              if(factors[p] == 0) 
              { 
                  ar.add(p);
                  factors[p]=p;
                  for(int i = p*p; i <= n; i += p) 
                      if(factors[i]==0)
                          factors[i] = p; 
              } 
          } 
          for(;p<=n;p++){
              if(factors[p] == 0) 
              { 
                  factors[p] = p;
                  ar.add(p);
              } 
          }
      }
  
      static void sort(int ar[]) {
          int n = ar.length;
          ArrayList<Integer> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static void sort1(long ar[]) {
          int n = ar.length;
          ArrayList<Long> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static void sort2(char ar[]) {
          int n = ar.length;
          ArrayList<Character> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static long ncr(long n, long r, long mod) {
          if (r == 0)
              return 1;
          long val = ncr(n - 1, r - 1, mod);
          val = (n * val) % mod;
          val = (val * modInverse(r, mod)) % mod;
          return val;
      }
  
      static long max[];
      static long lz[];
      
      // static void build(long a[], int v, int tl, int tr) {
      //     if (tl == tr) {
      //         max[v] = a[tl];
              
      //     } else {
      //         int tm = (tl + tr) / 2;
      //         build(a, v*2, tl, tm);
      //         build(a, v*2+1, tm+1, tr);
      //         max[v] = max[v*2] + max[v*2+1];
      //     }
      // }
  
      // static void push(int v, int tl, int tr){
      //     if(tl==tr){
      //         lz[v] = 0;
      //         return;
      //     }
      //     max[2*v] += lz[v];
      //     // max[2*v] %= m;
      //     max[2*v+1] += lz[v];
      //     // max[2*v+1] %= m;
      //     lz[2*v] += lz[v];
      //     lz[2*v] %= m;
      //     lz[2*v+1] += lz[v];
      //     lz[2*v+1] %= m;
      //     lz[v] = 0;
      // }
  
      static void update(int v, int tl, int tr, int l, int r, long val) {
          if(tl>r||tr<l)
              return;
          if(tl>=l&&tr<=r){
              max[v] = Math.max(val, max[v]);
              return;
          }
          int tm = ((tl + tr) >> 1);
          update(v*2, tl, tm, l, r, val);
          update(v*2+1, tm+1, tr, l, r, val);
          max[v] = Math.max(max[2*v],max[2*v+1]);
      }
  
      static long get(int v, int tl, int tr, int l, int r) {
          if(l>tr||r<tl)
              return 0;
          if (tl >= l && tr <= r) {
              return max[v];
          }
          int tm = ((tl + tr) >> 1);
          return Math.max(get(2*v, tl, tm, l, r), get(2*v+1, tm+1, tr, l, r));
      }
  
      // static int y = 0;
  
      static int parent[];
      static int rank[];
  
      static long m = 0;
  
      static int find_set(int v) {
          if (v == parent[v])
              return v;
          return find_set(parent[v]);
      }
      
      static void make_set(int v) {
          parent[v] = v;
          rank[v] = 1;
      }
      
      static void union_sets(int a, int b) {
          a = find_set(a);
          b = find_set(b);
          if (a != b) {
              if (rank[a] < rank[b]){
                  int tmp = a;
                  a = b;
                  b = tmp;
              }
              parent[b] = a;
              // if (rank[a] == rank[b])
              //     rank[a]++;
              rank[a] += rank[b];
              max1 = Math.max(max1,rank[a]);
              // System.out.println(a+" "+b+" "+rank[a]+" "+rank[b]);
          }
      }
  
      static int parent1[];
      static int rank1[];
  
      static int find_set1(int v) {
          if (v == parent1[v])
              return v;
          return find_set1(parent1[v]);
      }
      
      static void make_set1(int v) {
          parent1[v] = v;
          rank1[v] = 1;
      }
      
      static void union_sets1(int a, int b) {
          a = find_set1(a);
          b = find_set1(b);
          if (a != b) {
              if (rank1[a] < rank1[b]){
                  int tmp = a;
                  a = b;
                  b = tmp;
              }
              parent1[b] = a;
              // if (rank1[a] == rank1[b])
              //     rank1[a]++;
              rank1[a] += rank1[b];
          }
      }
  
      static long max1 = 0;
  
      static int count = 0;
      static int count1 = 0;
  
      public static void solve(InputReader sc, PrintWriter pw){
          int i, j = 0;
          // int t = 1; 
          long mod = 998244353;
          // int factors[] = new int[1000001];
          // ArrayList<Integer> ar = new ArrayList<>();
          // sieveOfEratosthenes(1000000, factors, ar);
          // HashSet<Integer> set = new HashSet<>();
          // for(int x:ar){
          //     set.add(x);
          // }
          int t = sc.nextInt();
          u: while (t-- > 0) {
              int n = sc.nextInt();
              int k = sc.nextInt();
              int a[] = new int[n];
              for(i=0;i<n;i++){
                  a[i] = sc.nextInt();
              }
              sort(a);
              ArrayList<Long> ar = new ArrayList<>();
              long u = 0;
              int v = 0;
              for(i=0;i<n;i++){
                  if(a[i]>=0){
                      if(u>0){
                          ar.add(u);
                          u = v = 0;
                      }
                      break;
                  }
                  else{
                      v++;
                      u = Math.max(u,-1*a[i]);
                      if(v==k){
                          ar.add(u);
                          u = v = 0;
                      }
                  }
              }
              if(u>0){
                  ar.add(u);
                  u = 0;
              }
              // for(;i<n&&a[i]==0;i++);
              u = v = 0;
              for(i=n-1;i>=0;i--){
                  if(a[i]<=0){
                      if(u>0){
                          ar.add(u);
                          u = v = 0;
                      }
                      break;
                  }
                  else{
                      v++;
                      u = Math.max(u,a[i]);
                      // pw.println(u);
                      if(v==k){
                          ar.add(u);
                          u = v = 0;
                      }
                  }
              }
              if(u>0){
                  ar.add(u);
                  u = 0;
              }
              Collections.sort(ar);
              long sum = 0;
              for(i=0;i<ar.size()-1;i++){
                  sum += 2*ar.get(i);
              }
              if(ar.size()>0)
                  sum += ar.get(i);
              pw.println(sum);
          }
      }
  
      static void KMPSearch(char pat[], char txt[], int pres[]){
          int M = pat.length;
          int N = txt.length;
          int lps[] = new int[M];
          int j = 0; 
          computeLPSArray(pat, M, lps);
          int i = 0;
          while (i < N) {
              if (pat[j] == txt[i]) {
                  j++;
                  i++;
              }
              if (j == M) {
                  pres[i-1] = 1;
                  j = lps[j - 1];
              }
              else if (i < N && pat[j] != txt[i]) {
                  if (j != 0)
                      j = lps[j - 1];
                  else
                      i = i + 1;
              }
          }
      }
    
      static void computeLPSArray(char pat[], int M, int lps[])
      {
          int len = 0;
          int i = 1;
          lps[0] = 0; 
          while (i < M) {
              if (pat[i] == pat[len]) {
                  len++;
                  lps[i] = len;
                  i++;
              }
              else 
              {
                  if (len != 0) {
                      len = lps[len - 1];
                  }
                  else
                  {
                      lps[i] = len;
                      i++;
                  }
              }
          }
      }
  
      static long[][] matrixMult(long a[][], long b[][], long mod){
          int n = a.length;
          int m = a[0].length;
          int p = b[0].length;
          long c[][] = new long[n][p];
          for(int i=0;i<n;i++){
              for(int j=0;j<m;j++){
                  for(int k=0;k<p;k++){
                      c[i][k] += a[i][j]*b[j][k];
                      c[i][k] %= mod;
                  }
              }
          }
          return c;
      }
  
      static long[][] exp(long mat[][], long b, long mod){
          if(b==0){
              int n = mat.length;
              long res[][] = new long[n][n];
              for(int i=0;i<n;i++){
                  res[i][i] = 1;
              }
              return res;
          }
          long half[][] = exp(mat, b/2, mod);
          long res[][] = matrixMult(half, half, mod);
          if(b%2==1){
              res = matrixMult(res, mat, mod);
          }
          return res;
      }
  
      static void countPrimeFactors(int num, int a[], HashMap<Integer,Integer> pos){
          for(int i=2;i*i<num;i++){
              if(num%i==0){
                  int y = pos.get(i);
                  while(num%i==0){
                      a[y]++;
                      num/=i;
                  }
              }
          }
          if(num>1){
              int y = pos.get(num);
              a[y]++;
          }
      }
  
      static void assignAnc(ArrayList<Integer> ar[], int depth[], int sz[], int par[][] ,int curr, int parent, int d){
          depth[curr] = d;
          sz[curr] = 1;
          par[curr][0] = parent;
          for(int v:ar[curr]){
              if(parent==v)
                  continue;
              assignAnc(ar, depth, sz, par, v, curr, d+1);
              sz[curr] += sz[v];
          }
      }
  
      static int findLCA(int a, int b, int par[][], int depth[]){
          if(depth[a]>depth[b]){
              a = a^b;
              b = a^b;
              a = a^b;
          }
          int diff = depth[b] - depth[a];
          for(int i=19;i>=0;i--){
              if((diff&(1<<i))>0){
                  b = par[b][i];
              }
          }
          if(a==b)
              return a;
          for(int i=19;i>=0;i--){
              if(par[b][i]!=par[a][i]){
                  b = par[b][i];
                  a = par[a][i];
              }
          }
          return par[a][0];
      }
  
      static void formArrayForBinaryLifting(int n, int par[][]){
          for(int j=1;j<20;j++){
              for(int i=0;i<n;i++){
                  if(par[i][j-1]==-1)
                      continue;
                  par[i][j] = par[par[i][j-1]][j-1];
              }
          }
      }
  
      static long lcm(int a, int b){
          return a*b/gcd(a,b);
      }
  
      static class Pair1 {
          long a;
          long b;
          
          Pair1(long a, long b) {
              this.a = a;
              this.b = b;
          }
      }
  
      static class Pair implements Comparable<Pair> {
          int a;
          int b;
          // int c;
          
          Pair(int a, int b) {
              this.a = a;
              this.b = b;
              // this.c = c;
          }
   
          public int compareTo(Pair p) {
              if(a!=p.a)
                  return p.a-a;
              return b-p.b;
          }
      }
  
      static class Pair2 implements Comparable<Pair2> {
          int a;
          int b;
          int c;
          
          Pair2(int a, int b, int c) {
              this.a = a;
              this.b = b;
              this.c = c;
          }
   
          public int compareTo(Pair2 p) {
              return a-p.a;
          }
      }
  
      static boolean isPrime(int n) { 
          if (n <= 1) 
              return false; 
          if (n <= 3) 
              return true; 
          if (n % 2 == 0 ||  n % 3 == 0) 
              return false; 
          for (int i = 5; i * i <= n; i = i + 6) 
              if (n % i == 0 || n % (i + 2) == 0) 
                  return false; 
          return true; 
      } 
  
      static long gcd(long a, long b) {
          if (b == 0)
              return a;
          return gcd(b, a % b);
      }
  
      static long fast_pow(long base, long n, long M) {
          if (n == 0)
              return 1;
          if (n == 1)
              return base % M;
          long halfn = fast_pow(base, n / 2, M);
          if (n % 2 == 0)
              return (halfn * halfn) % M;
          else
              return (((halfn * halfn) % M) * base) % M;
      }
  
      static long modInverse(long n, long M) {
          return fast_pow(n, M - 2, M);
      }
  
      static class InputReader {
          public BufferedReader reader;
          public StringTokenizer tokenizer;
  
          public InputReader(InputStream stream) {
              reader = new BufferedReader(new InputStreamReader(stream), 9992768);
              tokenizer = null;
          }
  
          public String next() {
              while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                  try {
                      tokenizer = new StringTokenizer(reader.readLine());
                  } catch (IOException e) {
                      throw new RuntimeException(e);
                  }
              }
              return tokenizer.nextToken();
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
      }
  }