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.Text;

class Program
{
	static void Main()
	{
		var hw = Array.ConvertAll(Console.ReadLine().Split(new[] { ' ' }), number => int.Parse(number));
		var h = hw[0];
		var w = hw[1];
		var count = h * 2;
		Console.ReadLine();
		var colors = Array.ConvertAll(Console.ReadLine().Split(new[] { ' ' }), number => int.Parse(number));

		var answer = new int[w + 2, h + 2];
		for (var y = 0; y < h; ++y) {
			for (var x = 0; x < w; ++x) {
				answer[x + 1, y + 1] = -1;
			}
		}

		var vectorX = 1;
		var vectorY = 0;
		var currentX = 1;
		var currentY = 1;
		for(var i = 0; i < colors.Length; ++i) {
			for (var j = 0; j < colors[i]; ++j) {
				answer[currentX, currentY] = i + 1;

				if (answer[currentX + vectorX, currentY + vectorY] != -1) {
					var newVectorX = vectorY * -1;
					vectorY = vectorX;
					vectorX = newVectorX;
				}

				currentX += vectorX;
				currentY += vectorY;
			}
		}

		for (var y = 0; y < h; ++y) {
			var line = new StringBuilder();
			for (var x = 0; x < w; ++x) {
				line.Append($"{answer[x + 1, y + 1]} ");
			}

			Console.WriteLine(line.ToString().Trim());
		}

		Console.ReadKey();
	}
}