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.Arrays;
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
    int H, W;
    int N;
    Color[] cs;
    int[][] ans;

    public static void main(String[] args) {
        Main m = new Main();
        m.read();
        m.solve();
    }

    private void read() {
        Scanner sc = new Scanner(System.in);
        H = sc.nextInt();
        W = sc.nextInt();
        N = sc.nextInt();
        cs = new Color[N];
        for (int i = 0; i < N; i++) {
            cs[i] = new Color(i+1, sc.nextInt());
        }
        ans = new int[H][W];
    }

    private void solve() {
        PriorityQueue<Color> queue =
                new PriorityQueue<>((c1, c2) -> Integer.compare(c2.num, c1.num));
        for (Color c: cs)
            queue.add(c);
        boolean flip = false;
        Color c = queue.poll();
        for (int i = 0; i < H; i++) {
            if (flip) {
                for (int j = W - 1; j >= 0; j--) {
                    if (c.num == 0)
                        c = queue.poll();
                    ans[i][j] = c.color;
                    c.num--;
                }
                flip = false;
            }
            else {
                for (int j = 0; j < W; j++) {
                    if (c.num == 0)
                        c = queue.poll();
                    ans[i][j] = c.color;
                    c.num--;
                }
                flip = true;
            }
        }

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < H; i++) {
            for (int j = 0; j < W-1; j++) {
                sb.append(ans[i][j]);
                sb.append(" ");
            }
            sb.append(ans[i][W-1]);
            sb.append("\n");
        }
        System.out.println(sb.toString());
    }

    private class Color {
        int color;
        int num;
        Color(int c, int n) {
            color = c;
            num = n;
        }
    }
}