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.Text;

namespace AtTest.D_Challenge
{
    class ABC_069
    {
        static void Main(string[] args)
        {
            Method(args);
            Console.ReadLine();
        }

        static void Method(string[] args)
        {
            int[] hw = ReadInts();
            int n = ReadInt();
            int[] array = ReadInts();
            var colors = new int[n][];
            for (int i = 0; i < n; i++)
            {
                colors[i] = new int[2] { array[i], i };
            }
            Array.Sort(colors, (a, b) => a[0] - b[0]);
            var grid = new int[hw[0], hw[1]];
            bool forward = true;
            int x = 0;
            int y = 0;
            for (int i = 0; i < n; i++)
            {
                //Console.WriteLine(colors[i][0]);
                for (int j = 0; j < colors[i][0]; j++)
                {
                    grid[y, x] = colors[i][1] + 1;
                    x = forward ? x + 1 : x - 1;
                    if (forward && x == hw[1])
                    {
                        forward = false;
                        x--;
                        y++;
                    }
                    else if (!forward && x == -1)
                    {
                        forward = true;
                        x++;
                        y++;
                    }
                }
            }

            for (int i = 0; i < hw[0]; i++)
            {
                for (int j = 0; j < hw[1]; j++)
                {
                    Console.Write(grid[i, j] + " ");
                }
                Console.WriteLine();
            }
        }

        private static string Read() { return Console.ReadLine(); }
        private static int ReadInt() { return int.Parse(Read()); }
        private static long ReadLong() { return long.Parse(Read()); }
        private static double ReadDouble() { return double.Parse(Read()); }
        private static int[] ReadInts() { return Array.ConvertAll(Read().Split(), int.Parse); }
        private static long[] ReadLongs() { return Array.ConvertAll(Read().Split(), long.Parse); }
        private static double[] ReadDoubles() { return Array.ConvertAll(Read().Split(), double.Parse); }
    }
}