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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>

int compare_int(const void *a,const void *b){
  return *(long*)a-*(long*)b;
}

int main(void){
  int H,W,N;
  scanf("%d%d%d",&H,&W,&N);

  int a[N];
  int data[H*W];
  int ans[H][W];
  for(int i = 0;i < N;i++) scanf("%d",&a[i]);

  int counter = 0;
  for(int i = 0;i < N;i++){
    int num = a[i];
    while(num > 0){
      data[counter+num-1] = i+1;
      num--;
    }
    counter += a[i];
  }

  counter = 0;
  for(int i = 0;i < H;i++){
    if(i%2 == 0){
      for(int j = 0;j < W;j++){
        ans[i][j] = data[counter];
        counter++;
      }
    }else{
      for(int j = W-1;j >= 0;j--){
        ans[i][j] = data[counter];
        counter++;
      }
    }
  }

  for(int i = 0;i < H;i++){
    for(int j = 0;j < W;j++){
      printf("%d",ans[i][j]);
      if(j == W-1) printf(" ");
    }
    printf("\n");
  }


  return 0;
}