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.Text;
using System.Collections.Generic;
using System.Linq;
using E = System.Linq.Enumerable;

class Program
{
    static void Main(string[] args)
    {
      
        //入力を受け取る
        var HW = Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToArray();
        var H = HW[0];
        var W = HW[1];
        var N = long.Parse(Console.ReadLine());
        var A = Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToArray();
        var point = 0; //色を決めるポインター
        var ans = new long[H][];
        for(int i = 0; i< H ;i++){
          ans[i] = new long[W];
        }
      
        var flag = true;
        for(long i = 0;i < H;i++){
          if(flag){
            for(long j = W-1;j >= 0;j--){
              if(A[point] == 0){
                point++;
              }
              ans[i][j] = point+1;
              A[point]--;
            }
            flag = false;
          }else{
            for(long j = 0;j < W;j++){
              if(A[point] == 0){
                point++;
              }
              ans[i][j] = point+1;
              A[point]--;
            }
            flag = true;
          }
        }
      
      for(int i = 0; i< H ;i++){
        Console.WriteLine(String.Join(" ",ans[i]));
      }
    }
}