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():
    h, w = map(int, input().split())
    n = int(input())
    a = list(map(int, input().split()))

    grid = [[0 for j in range(w)] for i in range(h)]
    i, j, idx = 0, 0, 0
    while idx < n:
        while 0 < a[idx]:
            grid[i][j] = idx + 1
            a[idx] -= 1

            if i % 2 == 0:
                j += 1
                if j == w:
                    j = w - 1
                    i += 1
            else:
                j -= 1
                if j == -1:
                    j = 0
                    i += 1
        idx += 1

    for i in range(h):
        print(" ".join([str(j) for j in grid[i]]))


if __name__ == '__main__':
    main()