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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;

public class Main {
	public static void main(String args[]) {
		Scanner input = new Scanner(System.in);
		int H = input.nextInt();
		int W = input.nextInt();
		int N = input.nextInt();
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = input.nextInt();
		}

		int[][] mat = new int[H][W];
		int dir = 0;
		int ind = 0;
		for (int r = 0; r < mat.length; r++) {
			if (dir % 2 == 0) {
				for (int c = 0; c < mat[0].length; c++) {
					mat[r][c] = ind + 1;

					if (arr[ind] > 0) {
						arr[ind]--;
						if (arr[ind] == 0) {
							ind++;
						}
					}
				}
			} else {
				for (int c = mat[0].length - 1; c >= 0; c--) {
					mat[r][c] = ind + 1;
					
					if (arr[ind] > 0) {
						arr[ind]--;
						if (arr[ind] == 0) {
							ind++;
						}
					}
				}

			}
			dir++;
		}
		for (int r = 0; r < mat.length; r++) {
			for (int c = 0; c < mat[0].length; c++) {
				System.out.print(mat[r][c] + " ");
			}
			System.out.println();
		}
	}
}