Problem:
Score : 400 points

Problem Statement

We have a grid with H rows and W columns of squares.
Snuke is painting these squares in colors 1, 2, ..., N.
Here, the following conditions should be satisfied:

For each i (1 ≤ i ≤ N), there are exactly a_i squares painted in Color i. Here, a_1 + a_2 + ... + a_N = H W.

For each i (1 ≤ i ≤ N), the squares painted in Color i are 4-connected. That is, every square painted in Color i can be reached from every square painted in Color i by repeatedly traveling to a horizontally or vertically adjacent square painted in Color i.

Find a way to paint the squares so that the conditions are satisfied.
It can be shown that a solution always exists.

Constraints

1 ≤ H, W ≤ 100

1 ≤ N ≤ H W

a_i ≥ 1

a_1 + a_2 + ... + a_N = H W

Input

Input is given from Standard Input in the following format:

H W
N
a_1 a_2 ... a_N

Output

Print one way to paint the squares that satisfies the conditions.
Output in the following format:

c_{1 1} ... c_{1 W}
:
c_{H 1} ... c_{H W}

Here, c_{i j} is the color of the square at the i-th row from the top and j-th column from the left.

Sample Input 1

2 2
3
2 1 1

Sample Output 1

1 1
2 3

Below is an example of an invalid solution:

1 2
3 1

This is because the squares painted in Color 1 are not 4-connected.

Sample Input 2

3 5
5
1 2 3 4 5

Sample Output 2

1 4 4 4 3
2 5 4 5 3
2 5 5 5 3

Sample Input 3

1 1
1
1

Sample Output 3

1

Solution in Kotlin (1.3.71) (judge verdict: Accepted)

fun main(args : Array<String>) {
    val (h, w) = readLine()!!.split(" ").map { it.toInt() }
    val n = readLine()!!.toInt()
    val aa = readLine()!!.split(" ").map { it.toInt() }

    var tmp = mutableListOf<Int>()
    var num = 1
    var isForward = true
    var ans = mutableListOf<String>()

    aa.forEach { a ->
        repeat(a) {
            tmp.add(num)
            if (tmp.size % w == 0) {
                if (isForward) {
                    ans.add(tmp.joinToString(separator = " "))
                } else {
                    ans.add(tmp.reversed().joinToString(separator = " "))
                }
                tmp = mutableListOf()
                isForward = !isForward
            }
        }
        num++
    }

    println(ans.joinToString(separator = System.lineSeparator()))
}