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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
#define  rep(i,n) for(li i=0;i<(n);i++)
#define  red(i,n) for(li i=(n)-1;i>=0;i--)
#define  all(a)   begin(a),end(a)
#define  pb(a)    push_back(a) 
using namespace std;
using li = long long;
using vi = vector<li>;
using vs = vector<string>;


int main()
{
    int h,w,n,x=0,a;
    cin>>h>>w>>n;
    int ans[h*w];
    rep(i,n) {
        cin>>a;
        rep(j,a) ans[x+j]=i+1;
        x+=a;
    }
    rep(i,h){
        if(i%2==0) rep(j,w) cout<<ans[i*w+j]<<" ";
        else rep(j,w) cout<<ans[i*w+w-1-j]<<" ";
        cout<<endl;
    }
    return 0;
}