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>
using namespace std;
int main()
{
    std::ios::sync_with_stdio(false);	
	int h,w;
    cin>>h>>w;
    int n_colour;
    cin>>n_colour;
    vector<int> colour(n_colour);
    for(int i = 0 ; i < n_colour ; i++)
    {
        cin>>colour[i];
    }	
    int c = 0;
    queue<int> ans;
    stack<int> ans2;
    for(int i = 0 ; i < h ; i++)
    {
        for(int j = 0 ; j < w ; j++)
        {
            if(colour[c]==0)
            {
                c++;    
            }
            if(i%2==0)
            {
                ans.push(c+1);
            }
            else
            {
                ans2.push(c+1);
            }
            colour[c]--;
        }
        
        while(ans.size()>0)
        {
            cout<<ans.front()<<" ";
            ans.pop();
        }
        while(ans2.size()>0)
        {
            cout<<ans2.top()<<" ";
            ans2.pop();
        }
        
        cout<<" \n";
    }
    
    return 0;
}