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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using static MyIO;


public class D
{
	public static void Main()
	{
		int H = getInt();
		int W = getInt();
		int N = getInt();
		int[] a = new int[N+1];
		for(int i = 1; i <= N; i++)
			a[i] = getInt();		
		
		int[,] c = new int[H,W];
		int color = 1;
		int rest = a[1];
		for(int i = 0; i < H; i++)
		{
			for(int j = 0; j < W; j++)
			{
				c[i,j] = color;
				rest--;
				if(rest > 0)
					continue;
				
				if(color == N)
					break;

				color++;
				rest = a[color];
			}			
		}

		for(int i = 0; i < H; i++)
		{			
			for(int j = 0; j < W; j++)
				Console.Write("{0} ", (i % 2 == 0) ? c[i,j] : c[i,W-j-1]);
			Console.WriteLine();
		}
	}
}


public static class MyIO
{
	private static string[] args = null;
	private static int num = -1;
	private static int used = -1;

	private static string getArg()
	{
		if(used == num)
		{
			args = Console.ReadLine().Split(' ');
			num = args.Length;
			used = 0;
		}
		return args[used++];
	}

	public static int getInt(){ return int.Parse(getArg()); }
	public static long getLong(){ return long.Parse(getArg()); }
	public static double getDouble(){ return double.Parse(getArg()); }
	public static string getString(){ return getArg(); }
}