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)

function Main(input) {
  input = input.split("\n");
  var h = parseInt(input[0].split(" ")[0]);
  var w = parseInt(input[0].split(" ")[1]);
  var n = parseInt(input[1]);
  tmp = input[2].split(" ");
  a=new Array(n).fill(0);
  for(i=0;i<n;i++){
    a[i]=parseInt(tmp[i]);
  }
  var ans ="";
  c = new Array(h).fill(0);
  for(i=0;i<h;i++){
    csub = new Array(w).fill(0);
    c[i]=csub;
  }
  d = new Array();
  for(i=0;i<n;i++){
    for(j=0;j<a[i];j++){
      d.push(i+1);
    }
  }
  for(i=0;i<h;i++){
    if(i%2!=1){
      for(j=0;j<w;j++){
        c[i][j]=d[i*w+j];
      }
    }else{
      for(j=0;j<w;j++){
        c[i][j]=d[(i+1)*w-j];
      }
    }
  }
  for(i=0;i<h;i++){
    if(i%2!=1){
      for(j=0;j<w;j++){
        if(j%w!=w-1){
        ans+=d[i*w+j]+" ";
        }else{
        ans+=d[i*w+j]+"\n";
        }
      }
    }else{
      for(j=0;j<w;j++){
        if(j%w!=w-1){
        ans+=d[(i+1)*w-j-1]+" ";
        }else{
          ans+=d[(i+1)*w-j-1]+"\n";
        }
      }
    }
  }
  ans=ans.substr(0,ans.length-1);
  console.log('%s', ans);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));