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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.lang.*;
import java.io.*;
class Pair<E,F>{
    E first;
    F second;
    public Pair(E first, F second){
        this.first=first;
        this.second=second;
    }
    public E getFirst(){return first;}
    public F getSecond(){return second;}
    public String toString(){
        return "<"+first.toString()+","+second.toString()+">";
    }
    public int hashCode(){
        return first.hashCode()*30011+second.hashCode()+2;
    }
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Pair another = (Pair) obj;
        return this.getFirst().equals(another.getFirst())&&this.getSecond().equals(another.getSecond());
    }
}
public class Main {
    public static Pair<Integer,Integer> numToCood(int H, int W, int n){
        int h = n/(2*W);
        int w = n%(2*W);
        if(w<W) return new Pair<>(2*h,w);
        else return new Pair<>(2*h+1,2*W-w-1);
    }
    public static void printArray(int[] array){
        int W = array.length;
        for(int w=0;w<W;w++){
        	System.out.print(array[w]);
        	if(w==W-1)System.out.println();
        	else System.out.print(" ");
        }
    }
    public static void printArray(int[][] array){
        int H = array.length;
        for(int h=0;h<H;h++) printArray(array[h]);
    }
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int H = sc.nextInt();
        int W = sc.nextInt();
        int N = sc.nextInt();
        int[] a = new int[N];
        for(int n=0;n<N;n++) a[n]=sc.nextInt();
        int[][] grid = new int[H][W];
        int color=1;
        int painted=0;
        for(int i=0;i<H*W;i++){
        	if(painted<a[color-1]){
        	    Pair<Integer,Integer> cood = numToCood(H,W,i);
        	    grid[cood.getFirst()][cood.getSecond()] = color;
        	    painted++;
        	}else{
        	    color++;
        	    painted=0;
        	    i--;
        	}
        }
        printArray(grid);
    }
}