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 <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int h,w;
int n,m;
vector <int> a;
int cou=0,dir=0;

int main(){
	cin>>h>>w>>n;
	for(int i=0;i<n;i++){
		cin>>m;
		for(int j=0;j<m;j++){
			if(cou<w-1){
				a.push_back(i+1);
				cou++;
			}else{
				a.push_back(i+1);
				if(dir==0){
					for(int k=0;k<w;k++){
						if(k<w-1){
							cout<<a[k]<<" ";
						}else{
							cout<<a[k]<<endl;
						}
					}
					dir=1;
				}else{
					for(int k=0;k<w;k++){
						if(k<w-1){
							cout<<a[w-k-1]<< " ";
						}else{
							cout<<a[w-k-1]<< endl;
						}
					}
					dir=0;
				}
				cou=0;
				a.erase(a.begin(),a.begin()+w);
			}
		}
	}
	return 0;
}