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;

public class P
{
    public int x { get; set; }
    public int y { get; set; }
}

public class Hello
{
    public static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var h = int.Parse(line[0]);
        var w = int.Parse(line[1]);
        var n = int.Parse(Console.ReadLine().Trim());
        line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        var ans = getAns0(h, w, n, a);
        print(h, w, ans);
    }
    static void print(int h, int w, int[,] a)
    {
        var t = new int[w];
        for (int i = 0; i < h; i++)
        {
            for (int j = 0; j < w; j++)
                t[j] = a[i, j];
            Console.WriteLine(string.Join(" ", t));
        }
    }
    static int[,] getAns0(int h, int w, int n, int[] a)
    {
        var t = new int[h, w];
        for (int i = 0; i < (h + 1) / 2; i++)
            for (int j = 0; j < w; j++)
            {
                if (2 * i < h) t[2 * i, j] = 2 * w * i + j;
                if (2 * i + 1 < h) t[2 * i + 1, j] = 2 * w * (i + 1) - j - 1;
            }
        var ps = new P[h * w];
        for (int i = 0; i < h; i++)
            for (int j = 0; j < w; j++)
                ps[t[i, j]] = new P { x = i, y = j };
        var pos = 0;
        var ans = new int[h, w];
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < a[i]; j++)
            {
                var c = ps[pos++];
                ans[c.x, c.y] = i + 1;
            }
        }
        return ans;
    }
}