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.Linq;
using System.Collections.Generic;
using System;

public class P
{
    public int x { get; set; }
    public int y { get; set; }
    public int d { get; set; }
    public int p { 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 aa = new int[h * w];
        var p = 0;
        for (int i = 0; i < n; i++)
            for (int j = 0; j < a[i]; j++)
                aa[p++] = i + 1;
        var ans = getAns0(h, w, n, aa);
        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 dx = new int[] { 0, 1, 0, -1 };
        var dy = new int[] { 1, 0, -1, 0 };
        var hw = h * w;
        var t = new int[h, w];
        var q = new Queue<P>();
        q.Enqueue(new P { x = 0, y = 0, d = 0, p = 0 });
        while (q.Count() > 0)
        {
            var tt = q.Dequeue();
            if (tt.p == hw) continue;
            t[tt.x, tt.y] = a[tt.p];
            var nx = tt.x + dx[tt.d];
            var ny = tt.y + dy[tt.d];
            if (nx >= 0 && nx < h && ny >= 0 && ny < w && t[nx, ny] == 0)
                q.Enqueue(new P { x = nx, y = ny, d = tt.d, p = tt.p + 1 });
            else
            {
                var nd = (tt.d + 1) % 4;
                 nx = tt.x + dx[nd];
                 ny = tt.y + dy[nd];
                q.Enqueue(new P { x = nx, y = ny, d = nd, p = tt.p + 1 });
            }
        }
        return t;
    }
}