description: The Hat is a game of speedy explanation/guessing words (similar to Alias). It's fun. Try it! In this problem, we are talking about a variant of the game when the players are sitting at the table and everyone plays individually (i.e. not teams, but individual gamers play).
  
  n people gathered in a room with m tables (n ≥ 2m). They want to play the Hat k times. Thus, k games will be played at each table. Each player will play in k games.
  
  To do this, they are distributed among the tables for each game. During each game, one player plays at exactly one table. A player can play at different tables.
  
  Players want to have the most "fair" schedule of games. For this reason, they are looking for a schedule (table distribution for each game) such that:
  
    * At any table in each game there are either ⌊n/m⌋ people or ⌈n/m⌉ people (that is, either n/m rounded down, or n/m rounded up). Different numbers of people can play different games at the same table.
    * Let's calculate for each player the value b_i — the number of times the i-th player played at a table with ⌈n/m⌉ persons (n/m rounded up). Any two values of b_imust differ by no more than 1. In other words, for any two players i and j, it must be true |b_i - b_j| ≤ 1. 
  
  
  
  For example, if n=5, m=2 and k=2, then at the request of the first item either two players or three players should play at each table. Consider the following schedules:
  
    * First game: 1, 2, 3 are played at the first table, and 4, 5 at the second one. The second game: at the first table they play 5, 1, and at the second — 2, 3, 4. This schedule is not "fair" since b_2=2 (the second player played twice at a big table) and b_5=0 (the fifth player did not play at a big table).
    * First game: 1, 2, 3 are played at the first table, and 4, 5 at the second one. The second game: at the first table they play 4, 5, 2, and at the second one — 1, 3. This schedule is "fair": b=[1,2,1,1,1] (any two values of b_i differ by no more than 1). 
  
  
  
  Find any "fair" game schedule for n people if they play on the m tables of k games.
  
  Input
  
  The first line of the input contains an integer t (1 ≤ t ≤ 10^4) — the number of test cases in the test.
  
  Each test case consists of one line that contains three integers n, m and k (2 ≤ n ≤ 2⋅10^5, 1 ≤ m ≤ ⌊n/2⌋, 1 ≤ k ≤ 10^5) — the number of people, tables and games, respectively.
  
  It is guaranteed that the sum of nk (n multiplied by k) over all test cases does not exceed 2⋅10^5.
  
  Output
  
  For each test case print a required schedule — a sequence of k blocks of m lines. Each block corresponds to one game, a line in a block corresponds to one table. In each line print the number of players at the table and the indices of the players (numbers from 1 to n) who should play at this table.
  
  If there are several required schedules, then output any of them. We can show that a valid solution always exists.
  
  You can output additional blank lines to separate responses to different sets of inputs.
  
  Example
  
  Input
  
  
  3
  5 2 2
  8 3 1
  2 1 3
  
  
  Output
  
  
  3 1 2 3
  2 4 5
  3 4 5 2
  2 1 3
  
  2 6 2
  3 3 5 1
  3 4 7 8
  
  2 2 1
  2 2 1
  2 2 1
solution: // package c1619;
  
  import java.io.File;
  import java.lang.invoke.MethodHandles;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Random;
  import java.util.Scanner;
  
  //
  // Codeforces Round #762 (Div. 3) 2021-12-20 06:35
  // F. Let's Play the Hat?
  // https://codeforces.com/contest/1619/problem/F
  // time limit per test 2 seconds; memory limit per test 256 megabytes
  // public class Pseudo for 'Source should satisfy regex [^{}]*public\s+(final)?\s*class\s+(\w+).*'
  //
  // n people gathered in a room with m tables (n >= 2m). They want to play the Hat k times. Thus, k
  // games will be played at each table. Each player will play in k games.
  //
  // To do this, they are distributed among the tables for each game. During each game, one player
  // plays at exactly one table. A player can play at different tables.
  //
  // Players want to have the most "fair" schedule of games. For this reason, they are looking for a
  // schedule (table distribution for each game) such that:
  //  * At any table in each game there are either \lfloor\frac{n}{m}\rfloor people or
  //    \lceil\frac{n}{m}\rceil people (that is, either n/m rounded down, or n/m rounded up).
  //    Different numbers of people can play different games at the same table.
  //  * Let's calculate for each player the value b_i -- the number of times the i-th player played at
  //    a table with \lceil\frac{n}{m}\rceil persons (n/m rounded up). Any two values of b_imust
  //    differ by no more than 1. In other words, for any two players i and j, it must be true |b_i -
  //    b_j| <= 1.
  //
  // For example, if n=5, m=2 and k=2, then at the request of the first item either two players or
  // three players should play at each table. Consider the following schedules:
  //  * First game: 1, 2, 3 are played at the first table, and 4, 5 at the second one. The second
  //    game: at the first table they play 5, 1, and at the second -- 2, 3, 4. This schedule is since
  //    b_2=2 (the second player played twice at a big table) and b_5=0 (the fifth player did not play
  //    at a big table).
  //  * First game: 1, 2, 3 are played at the first table, and 4, 5 at the second one. The second
  //    game: at the first table they play 4, 5, 2, and at the second one -- 1, 3. This schedule is :
  //    b=[1,2,1,1] (any two values of b_i differ by no more than 1).
  //
  // Find any "fair" game schedule for n people if they play on the m tables of k games.
  //
  // Input
  //
  // The first line of the input contains an integer t (1 <= t <= 10^4) -- the number of test cases in
  // the test.
  //
  // Each test case consists of one line that contains three integers n, m and k (2 <= n <= 2*10^5, 1
  // <= m <= \lfloor\frac{n}{2}\rfloor, 1 <= k <= 10^5) -- the number of people, tables and games,
  // respectively.
  //
  // It is guaranteed that the sum of nk (n multiplied by k) over all test cases does not exceed
  // 2*10^5.
  //
  // Output
  //
  // For each test case print a required schedule -- a sequence of k blocks of m lines. Each block
  // corresponds to one game, a line in a block corresponds to one table. In each line print the
  // number of players at the table and the indices of the players (numbers from 1 to n) who should
  // play at this table.
  //
  // If there are several required schedules, then output any of them. We can show that a valid
  // solution always exists.
  //
  // You can output additional blank lines to separate responses to different sets of inputs.
  //
  // Example
  /*
  input:
  3
  5 2 2
  8 3 1
  2 1 3
  
  output:
  3 1 2 3
  2 4 5
  3 4 5 2
  2 1 3
  
  2 6 2
  3 3 5 1
  3 4 7 8
  
  2 2 1
  2 2 1
  2 2 1
  */
  //
  public class C1619F {
    static final int MOD = (int)1e9+7;
    static final Random RAND = new Random();
  
    static List<List<Integer>> solve(int n, int m, int k) {
      List<List<Integer>> ans = new ArrayList<>();
      int offset = 0;
      for (int i = 0; i < k; i++) {
        int h = n % m;  // number of big tables
        int sb = (n + m - 1) / m;  // size of each big table
        int sn = n / m;  // size of each normal table
        for (int j = 0; j < h; j++) {
          List<Integer> table = new ArrayList<>();
          table.add(sb);
          for (int l = 0; l < sb; l++) {
            table.add(1 + (j * sb + l + offset) % n);
          }
          ans.add(table);
        }
        offset = (offset + h * sb) % n;
        for (int j = 0; j < m - h; j++) {
          List<Integer> table = new ArrayList<>();
          table.add(sn);
          for (int l = 0; l < sn; l++) {
            table.add(1 + (offset + j * sn + l) % n);
          }
          ans.add(table);
        }
      }
      return ans;
    }
  
    public static void main(String[] args) {
      Scanner in = getInputScanner();
      int T = in.nextInt();
      for (int t = 1; t <= T; t++) {
        int n = in.nextInt();
        int m = in.nextInt();
        int k = in.nextInt();
  
        List<List<Integer>> ans = solve(n, m, k);
        System.out.println(trace(ans));
      }
      in.close();
    }
  
    static String trace(List<List<Integer>> arr) {
      StringBuilder sb = new StringBuilder();
      for (List<Integer> v : arr) {
        for (int w : v) {
          sb.append(w);
          sb.append(' ');
        }
        sb.append("\n");
      }
      return sb.toString();
    }
  
    static Scanner getInputScanner() {
      try {
        final String USERDIR = System.getProperty("user.dir");
        final String CNAME = MethodHandles.lookup().lookupClass().getSimpleName();
        final File fin = new File(USERDIR + "/io/c" + CNAME.substring(1,5) + "/" + CNAME + ".in");
        return fin.exists() ? new Scanner(fin) : new Scanner(System.in);
      } catch (Exception e) {
        return new Scanner(System.in);
      }
    }
  }
  