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: Wrong Answer)

using System.Collections.Generic;
using System.Linq;
using System;
class Program
{
	static void Main()
	{
        var line1 = Console.ReadLine();
        var first = line1.Split(' ');
        int height = int.Parse(first[0]);
        int width = int.Parse(first[1]);

        var line2 = Console.ReadLine();
        string[] aaa = line2.Split(' ');
        int colorKind = int.Parse(aaa[0]);

        var line3 = Console.ReadLine();
        string[] colorsStr = line3.Split(' ');
        int[] colors = new int[colorKind];

        for (int i = 0; i < colorKind; i++){
            colors[i] = int.Parse(colorsStr[i]);
        }

        int[] grid = new int[width * height];
        int index = 0;
        for (int i = 0; i < colorKind; i++){
            for (int y = 0; y < colors[i]; y++){
                grid[index] = (i + 1);
                index++;
            }
        }

        string a = "";
        bool isReverse = false;
        for (int i = 0; i < height; i++)
		{
            string b = "";
            for (int y = 0; y < width; y++){
                b += grid[i * width + y];
            }
            if(isReverse){
				char[] c = b.ToCharArray();
				Array.Reverse(c);
				b = new string(c);
            }
            a += b + "\n";
            isReverse = !isReverse;
		}
        Console.WriteLine(a);
	}
}