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 Scala (2.11.7) (judge verdict: Wrong Answer)

import java.io.{BufferedReader, InputStream, InputStreamReader}
import java.util.StringTokenizer

import scala.util.Sorting

object Main {

  val MOD = 1000000007

  def solve(): Unit = {
    val sc = new FastScanner(System.in)
    val H = sc.nextInt
    val W = sc.nextInt
    val N = sc.nextInt
    val a = Array.ofDim[(Int, Int)](N)
    (0 until N) foreach { i =>
      a(i) = (i + 1, sc.nextInt)
    }
    Sorting.quickSort(a)(Ordering.by((_: (Int, Int))._2))
    var cur = 0
    (0 until H) foreach { h =>
      val row = ((0 until W) map { _ =>
        if (a(cur)._2 == 0) cur += 1
        val i = a(cur)._1
        a(cur) = (i, a(cur)._2 - 1)
        i
      }).mkString(" ")
      println(if ((h & 1) == 0) row else row.reverse)
    }
  }

  def main(args: Array[String]): Unit = {
    solve()
  }

  class FastScanner(val stream: InputStream) {
    val in = new BufferedReader(new InputStreamReader(stream))
    var st: StringTokenizer = _

    def next: String = {
      while (st == null || !st.hasMoreTokens) {
        val rl = in.readLine
        if (rl == null) return null
        st = new StringTokenizer(rl)
      }
      st.nextToken
    }

    def nextInt: Int = next.toInt
  }
}