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 Regular80
{
    public class GridColor
    {
        private int height;
        private int width;
        private int N;
        private int[] nums;
        private int[] sums;
        public GridColor(int height, int width, int N, int[] nums)
        {
            this.height = height;
            this.width = width;
            this.N = N;
            this.nums = nums;
            sums = new int[N];
            for (int i = 0; i < N; i++)
            {
                sums[i] = nums.Take(i+1).Sum();
            }
        }

        public void Run()
        {
            var colorArray = GetColorArray();
            Write(colorArray);

        }
        public int[,] GetColorArray()
        {
            var colorRec = new int[height, width];
            int indicator = 0;
            for (int i = 0; i < height; i++)
            {
                bool isEven = i % 2 == 0;
                int j = isEven ? 0 : width - 1;
                int inc = isEven ? 1 : -1;
                int jStop = isEven ? width : -1;
                while (j != jStop)
                {
                    colorRec[i, j] = Coloring(indicator);
                    indicator++;
                    j += inc;
                }
            }
            return colorRec;
        }
        public int Coloring(int indicator)
        {
            foreach(var n in sums)
            {
                if (indicator < n)
                    return Array.IndexOf(sums, n) + 1;
            }
            return 0;
        }

        public void Write(int[,] colorArray)
        {
            for(int i = 0; i< height; i++)
            {
                for(int j = 0; j< width; j++)
                {
                    if (j < width - 1)
                        Console.Write("{0} ", colorArray[i, j]);
                    else
                        Console.WriteLine("{0}", colorArray[i, j]);
                }
            }
        }

    }


    class Program
    {
        static void Main(string[] args)
        {
            var gridLength = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            var height = gridLength[0];
            var width = gridLength[1];
            var N = int.Parse(Console.ReadLine());
            var nums = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();

            if (nums.Count() != N)
                throw new ArgumentException("");

            var gridColor = new GridColor(height, width, N, nums);
            gridColor.Run();
        }
    }
}