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)

def main():
    from itertools import cycle

    H, W = map(int, input().split())
    N = int(input())
    *a, = map(int, input().split())

    g = [[-1] * (W + 2) for _ in range(H + 2)]
    for r in range(H + 1):
        g[r][0] = g[r][W + 1] = 0
    for c in range(W + 1):
        g[0][c] = g[H + 1][c] = 0

    def next_pos():
        dir_ = cycle([(1, 0), (0, 1), (-1, 0), (0, -1)])
        r, c = 1, 1
        cnt = 0

        dr, dc = next(dir_)
        while cnt < H * W:
            g[r][c] = cnt
            cnt += 1
            yield r - 1, c - 1
            if ~g[r + dr][c + dc]:
                dr, dc = next(dir_)
            r += dr
            c += dc

    gen_np = next_pos()

    ans = [[-1] * W for _ in range(H)]
    for i, x in enumerate(a, start=1):
        for _ in range(x):
            r, c = next(gen_np)
            ans[r][c] = i

    for row in ans:
        print(*row)


if __name__ == '__main__':
    main()