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.io.*;
import static java.lang.Long.max;
import static java.lang.Long.min;
import static java.lang.Math.abs;
import static java.lang.Math.pow;
import static java.util.Collections.sort;
public class Main {
    static long mod=998244353;
    static HashMap<Long,Integer> M=new HashMap();
    static FastReader in=new FastReader();
    static List<Integer >G[];
    public static void main(String [] args) {
      
       int x=in.nextInt(),z=in.nextInt();
       int n=in.nextInt();
       int a[]=new int[n+1];
       for(int i=1;i<=n;i++){a[i]=in.nextInt();}
        
       int l=n,ll=1;
       for(int i=1;i<=n;i++)if(a[i]==0)l=i;
       int c[][]=new int[x+1][z+1];
       
       for(int i=1;i<=n;i++)
           if(a[i]==0){l=i;}
       boolean B=!false,BB=false;
       for(int i=0,u=1,o=1;i<=n;i++){
           
       while(a[i]-->0){
       c[u][o]= i;
       if((o==1||o==z)&&(BB||z==1)){B=!B;u++;BB=false;}
       else if(B){o++;ll=0;BB=true;}
       else{o--;ll=0;BB=true;}
       
       }
      
       }
       for(int i=1;i<=x;i++){
           StringBuilder Sd=new StringBuilder();
           for(int u=1;u<=z;u++){
           Sd.append((c[i][u]==0?l:c[i][u])+" ");
           }
           System.out.println(Sd);
       }
    }
    
   
   
    static long gcd(long g,long x){
        if(x<1)return g;
        else return gcd(x,g%x);
    
    }
}
class node implements Comparable<node>{
int f, e;
node(int tt,int ll){
f=tt;e=ll;
}
    @Override
    public int compareTo(node o) {
    return f-o.f;    
    }
}
class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                     InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
}
 
class Sorting{
 
 public static int[] bucketSort(int[] array, int bucketCount) {
 
 if (bucketCount <= 0) throw new IllegalArgumentException("Invalid bucket count");
 
 if (array.length <= 1) return array; //trivially sorted
 
 
 
 int high = array[0];
 
 int low = array[0];
 
 for (int i = 1; i < array.length; i++) { //find the range of input elements
 
 if (array[i] > high) high = array[i];
 
 if (array[i] < low) low = array[i];
 
 }
 
 double interval = ((double)(high - low + 1))/bucketCount; //range of one bucket
 
 
 ArrayList<Integer> buckets[] = new ArrayList[bucketCount];
 
 for (int i = 0; i < bucketCount; i++) { //initialize buckets
 
 buckets[i] = new ArrayList();
 
 }
 
 
 
 for (int i = 0; i < array.length; i++) { //partition the input array
 
 buckets[(int)((array[i] - low)/interval)].add(array[i]);
 
 }
 
 
 int pointer = 0;
 
 for (int i = 0; i < buckets.length; i++) {
 
 Collections.sort(buckets[i]); //mergeSort
 
 for (int j = 0; j < buckets[i].size(); j++) { //merge the buckets
 
 array[pointer] = buckets[i].get(j);
 
 pointer++;
 
 }
 
}
 
return array;
 
}
 
}