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.Generic;
using System.Linq;
using System.Text;

namespace AtCoder
{
    class Program
    {
        private static int[][] Solve(int H, int W, int[] A)
        {
            int[][] C = new int[H][];
            for (int i = 0; i < H; ++i) { C[i] = new int[W]; }
            int c = 0;
            for (int i = 0; i < H * W; ++i)
            {
                while (A[c] == 0) { ++c; }
                int h = i / W;
                int w = (h % 2 == 0) ? i % W : W - i % W - 1;
                C[h][w] = c + 1;
                --A[c];
            }
            return C;
        }
        static void Main(string[] args)
        {
            int[] values = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
            int N = int.Parse(Console.ReadLine());
            int[] A = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
            foreach (int[] c in Solve(values[0], values[1], A))
            {
                Console.WriteLine(string.Join(" ", c));
            }
        }
    }
}