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# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;
using System.Text;

namespace AtCoder.ABC
{
    class QuestionA
    {
        public static void Main(string[] args)
        {
            var hw = Console.ReadLine().Split(" ").Select(x => int.Parse(x)).ToArray();
            var h = hw[0];
            var w = hw[1];

            var n = int.Parse(Console.ReadLine());
            var a = Console.ReadLine().Split(" ").Select(x => int.Parse(x)).ToArray();

            var ans = "";

            for(int i = 0; i < n; i++) {
                var nakami = i + 1;
                for (int j = 0; j < a[i]; j++) {
                    ans += nakami;
				}
			}

            var list = new List<string>();

            for(int i = 0; i < h; i++) {
                var s = ans.Substring(i * w, w);
                if(i % 2 == 1) {
                    var temp = s.ToList();
                    temp.Reverse();
                    s = "";
                    foreach(var c in temp) {
                        s += c;
					}
				}

                for(int j = 0; j < s.Length; j++) {
                    Console.Write($"{s[j]}");
                    if(j == s.Length - 1) {
                        Console.WriteLine();
					} else {
                        Console.Write(" ");
					}
				}
			}
        }
    }
}