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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Arrays;
import java.util.Scanner;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

/**
 * 解説通りに作成したソースコード
 */
public class Main {

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int h = scanner.nextInt(), w = scanner.nextInt();
			int n = scanner.nextInt();
			int[] a = IntStream.range(0, n).map(i -> scanner.nextInt()).toArray();
			int[][] result = new int[h][w];
			int color = 1, currentX = 0, currentY = 0;
			for (int ai : a) {
				while (currentY + ai >= w) {
					// 改行が発生する
					fill(result, currentX, currentY, w, color);
					currentX++;
					ai -= (w - currentY);
					currentY = 0;
				}
				fill(result, currentX, currentY, currentY + ai, color);
				currentY += ai;
				color++;
			}
			IntStream.range(0, h).forEach(i -> println(result[i], i));
		}
	}

	/**
	 * 結果配列にx座標のy座標開始〜y座標終了-1までに色を塗る
	 * 
	 * @param result 結果配列
	 * @param x      x座標
	 * @param yStart y座標開始
	 * @param yEnd   y座標終了
	 * @param color  色
	 */
	private static void fill(int[][] result, int x, int yStart, int yEnd, int color) {
		for (int i = yStart; i < yEnd; i++) {
			result[x][i] = color;
		}
	}

	/**
	 * 数列を出力する
	 * 
	 * @param a      出力する数列
	 * @param lineNo 行数
	 */
	private static void println(int[] a, int lineNo) {
		if (0 == (lineNo & 1)) {
			// lineNoが偶数の場合，左から右へ出力する
			System.out.println(Arrays.stream(a).mapToObj(String::valueOf).collect(Collectors.joining(" ")));
		} else {
			// 右から左へ出力する
			System.out.println(IntStream.range(0, a.length).mapToObj(i -> String.valueOf(a[a.length - 1 - i]))
					.collect(Collectors.joining(" ")));
		}
	}
}