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>
int a[10000];
int b[100][100]={0};
int cnt;
int i;
void solve(int h,int w,int n){
    int j,k;
    if(i == n)return;
    if(cnt == a[i-1]){
      i++;
      cnt=0;
      return;
    }
    for(k=0;k<h;k++){
        for(j=0;j<w;j++){
          if(cnt == 0 && b[k][j] == 0){
            b[k][j] = i;
          }else{
            if(b[k][j] == 0 && (b[k-1][j] == i || b[k+1][j] == i || b[k][j+1] == i || b[k][j-1] == i)){
              b[k][j] = i;
            }else{
                goto end;
            }
          }
          cnt++;
          solve(h,w,n);
          end:
            continue;
        }
    }
    return;
}

int main(void){
    int h,w,n;
    scanf("%d %d",&h,&w);
    scanf("%d",&n);
    int k,j;
    for(k=0;k<n;k++){
        scanf("%d",&a[k]);
    }
    if(h == 1 && w == 1){
      printf("1");
      return 0;
    }
    i=1;
    cnt=0;
    solve(h,w,n);
    for(k=0;k<h;k++){
        for(j=0;j<w;j++){
            printf("%d ",b[k][j]);
        }
        printf("\n");
    }
    return 0;
}