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 Python (3.4.3) (judge verdict: Accepted)

from itertools import cycle, chain, repeat

# 入力
H, W = map(int, input().split())
N = int(input())
a = list(map(int, input().split()))

# (1, 1), (1, 2), ..., (1, W), (2, W), (2, W - 1), ..., (2, 2), (2, 1),
# (3, 1), (3, 2), ... の順で色1(1マス目), 色1(2マス目), ..., 色1(a_1マス目),
# 色2(1マス目), ..., 色2(a_2マス目), 色3(1マス目), ... と塗る
c = {
    (i, j): k
    for k, i, j in zip(
        chain(
            *(
                repeat(k, m)
                for k, m in enumerate(a, 1)
            )
        ),
        chain(
            *(
                repeat(r, W)
                for r in range(H)
            )
        ),
        cycle(
            chain(
                range(W),
                reversed(range(W)),
            )
        )
    )
}
ans = '\n'.join(
    ' '.join(
        str(c[(i, j)])
        for j in range(W)
    )
    for i in range(H)
)

# 出力
print(ans)