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 Rust (1.42.0) (judge verdict: Accepted)

fn main() {
    proconio::input! {
        h: usize,
        w: usize,
        n: usize,
        a_s: [usize; n],
    }
    let len_num_s = a_s
        .iter()
        .enumerate()
        .map(|(i, a)| (*a, i + 1))
        .collect::<Vec<(usize, usize)>>();
    let mut deque = std::collections::VecDeque::new();
    for (len, num) in len_num_s {
        for _ in 0..len {
            deque.push_back(num);
        }
    }
    let mut v = vec![vec![0; w]; h];
    for i in (0..h).step_by(2) {
        for j in 0..w {
            v[i][j] = deque.pop_front().unwrap();
        }
        if i + 1 != h {
            for j in (0..w).rev() {
                v[i + 1][j] = deque.pop_front().unwrap();
            }
        }
    }
    let ans = v
        .iter()
        .map(|item| {
            item.iter()
                .map(|i| i.to_string())
                .collect::<Vec<_>>()
                .join(" ")
        })
        .collect::<Vec<_>>()
        .join("\n");
    println!("{}", ans);
}