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 JavaScript (node.js v5.12) (judge verdict: Accepted)

"use strict";
    
const main = arg => {
    arg = arg.trim().split("\n");
    const H = parseInt(arg[0].split(" ")[0]);
    const W = parseInt(arg[0].split(" ")[1]);
    
    const N = parseInt(arg[1]);
    const A = arg[2].split(" ").map(n=>parseInt(n));
    
    let temp = [];
    
    if(H * W === 1) {
        console.log(1);
        return;
    }
    
    for(let i=1; i<=N; i++) {
        for(let j=0; j<A[i-1]; j++) {
            temp.push(i);
        }
    }

    let answer = [];
    let list = [];
    let currentH = 0;

    for(let i=0; i<temp.length; i++) {
        list.push(temp[i]);
        
        if(i !== 0 && (parseInt(i) + 1) % W === 0) {
            if(currentH % 2 !== 0) list.reverse()

            answer.push(list.join(" "));
            list = [];
            currentH++;
        }
    }
    
    console.log(answer.join("\n"));
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));