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: Wrong Answer)

#include<algorithm>
#include<functional>
#include<iostream>
#include<vector>
using namespace std;

int main(){
    int h, w, n, x=0;
    cin >> h >> w >> n;
    vector<int> A(n);
    vector<int> C(h*w);
    for(int i=0 ; i<n ; i++){
        cin >> A[i];
    }
    for(int j=0 ; j<n ; j++){
        for(int k=x ; k<x+A[j]; k++){
            C[k]=j+1;
        }
        x+=A[j];
    }
    for(int l=0 ; l<=h*(w-1) ; l+=2*w){
        sort(C.begin()+l, C.begin()+l+w, greater<int>());
    }
    for(int m=0 ; m<h*w ; m++){
        cout << C[m];
        if((m+1)%w==0){
            cout << endl;
        }else{
            cout << " ";
        }
    }
    return 0;
}