[SOLUTION !!!] Nastia and a Beautiful Matrix Solution Codeforces 2021

   

Nastia and a Beautiful Matrix Solution Codeforces 2021

SOLUTION

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You like numbers, don't you? Nastia has a lot of numbers and she wants to share them with you! Isn't it amazing?

Let ai be how many numbers i (1ik) you have.

An n×n matrix is called beautiful if it contains all the numbers you have, and for each 2×2 submatrix of the original matrix is satisfied:

  1. The number of occupied cells doesn't exceed 3;
  2. The numbers on each diagonal are distinct.

Make a beautiful matrix of minimum size.

Input

The first line contains a single integer t (1t10000) — the number of test cases.

The first line of each test case contains 2 integers m and k (1m,k105) — how many numbers Nastia gave you and the length of the array a, respectively.

The second line of each test case contains k integers a1,a2,,ak (0aima1+a2++ak=m), where ai is how many numbers i you have.

It's guaranteed that the sum of m and k in one test doesn't exceed 2105.

Output

For each t test case print a single integer n — the size of the beautiful matrix.

In the next n lines print n integers bi,j (0bi,jk; if position is empty, print bi,j=0) — the beautiful matrix b you made up.

Example
input
Copy
2
3 4
2 0 0 1
15 4
2 4 8 1
output
Copy
2
4 1
0 1
5
3 0 0 2 2
3 2 3 3 0
0 1 0 4 0
3 0 0 0 0
2 1 3 3 3
Note

Note that 0 in this problem represents a blank, not a number.

Examples of possible answers for the first test case:

114014104011

Examples of not beautiful matrices for the first test case:

104141711040

The example of the not beautiful matrix for the second test case:

3402232330010003000021333

Everything is okay, except the left-top submatrix contains 4 numbers.


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