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 (1.15.1) (judge verdict: Accepted)

pub fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

pub fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

pub fn read_vec2<T: std::str::FromStr>(n: usize) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}

pub fn read_col<T: std::str::FromStr>(n: usize) -> Vec<T> {
    (0..n).map(|_| read()).collect()
}

fn f(u: usize, p: usize, c: u64, edges: &Vec<Vec<(usize, u64)>>, depth: &mut Vec<u64>) {
    depth[u as usize] = c;
    for v in &edges[u] {
        if v.0 == p {
            continue;
        }
        f(v.0, u, c + v.1, edges, depth);
    }
}

fn main() {
    let hw: Vec<usize> = read_vec();
    let h = hw[0];
    let w = hw[1];
    let n: usize = read();
    let avec: Vec<usize> = read_vec();

    let mut mat: Vec<Vec<usize>> = vec![vec![0; w]; h];
    let mut color = 0;
    let mut cnt = avec[color];
    let mut b = true;
    for i in 0..h {
        for j1 in 0..w {
            let j;
            if b {
                j = j1;
            } else {
                j = w - 1 - j1;
            }
            if cnt == 0 {
                color += 1;
                cnt = avec[color];
            }
            mat[i][j] = color + 1;
            cnt -= 1;
        }
        b = !b;
    }

    for i in 0..h {
        for j in 0..w {
            print!("{}", mat[i][j]);
            if j < w - 1 {
                print!(" ");
            } else {
                println!("");
            }
        }
    }
}