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: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AtCoder.Abc
{
    class QuestionD
    {
        public static void Main(string[] args)
        {
            var sw = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);

            // 整数配列の入力
            var hw = Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();

            // 整数の入力
            var n = int.Parse(Console.ReadLine());

            // 整数配列の入力
            var a = Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();

            var maps = new int[hw[1]][];

            var reaches = new bool[hw[1]][];

            for(int i = 0; i < hw[0]; i++) {
                maps[i] = new int[hw[1]];
                reaches[i] = new bool[hw[1]];
            }

            var last = new int[] { 0, 0 };

            for(int i = 0; i < n; i++) {
                var ret = DFS(last[0] + 1, last[1], maps, reaches, i + 1, a[i], hw[0], hw[1]);
                if (ret[0] != -1 && ret[1] != -1) {
                    last = ret;
                    continue;
                }
                ret = DFS(last[0] - 1, last[1], maps, reaches, i + 1, a[i], hw[0], hw[1]);
                if (ret[0] != -1 && ret[1] != -1) {
                    last = ret;
                    continue;
                }
                ret = DFS(last[0], last[1] + 1, maps, reaches, i + 1, a[i], hw[0], hw[1]);
                if (ret[0] != -1 && ret[1] != -1) {
                    last = ret;
                    continue;
                }
            }

            for(int y = 0; y < hw[0]; y++) {
                for (int x = 0; x < hw[1]; x++) {
                    Console.Write(maps[y][x]);

                    if(x != hw[1] - 1) {
                        Console.Write(" ");
                    } else {
                        Console.WriteLine();
                    }
                }
            }

            Console.Out.Flush();
        }

        public static int[] DFS(int x, int y, int[][] maps, bool[][] reaches, int a, int num, int h, int w)
        {
            if(x < 0 || x >= w || y < 0 || y >= h || reaches[y][x] == true) {
                return new int[] { -1, -1 };
            }

            maps[y][x] = a;
            reaches[y][x] = true;

            num--;

            if(num == 0) {
                return new int[] { x, y };
            }

            //右
            var ret = DFS(x + 1, y, maps, reaches, a, num, h, w);
            if(ret[0] != -1 && ret[1] != -1) {
                return ret;
            }
            //左
            ret = DFS(x - 1, y, maps, reaches, a, num, h, w);
            if (ret[0] != -1 && ret[1] != -1) {
                return ret;
            }
            //↓
            ret = DFS(x, y + 1, maps, reaches, a, num, h, w);
            if (ret[0] != -1 && ret[1] != -1) {
                return ret;
            }

            return new int[] { -1, -1 };
        }
    }
}