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<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<cstdlib>
#include <cmath>
#include<stdio.h>
#include<queue>
#include<stack>
#include<set>
#define MAX 1000000000000000000LL
long long inf=1000000007;
using namespace std;
int main(){
    int h,w,n;
    cin>>h>>w>>n;
    int a[105];
    int color[105][105]={};
    
    for(int i=1; i<=n; i++){
        cin>>a[i];
    }
    
    int k=1;
    
    for(int i=1; i<=h; i++){
        for(int j=1; j<=w; j++){
            if(a[k]==0)k++;
            color[i][j]=k;
            a[k]--;
        }
    }
    
    for(int i=1; i<=h; i++){
        if(i%2==1){
            for(int j=1;j<w; j++){
                cout<<color[i][j]<<" ";
            }
            cout<<color[i][w];
        }
        else {
            for(int j=w;j>1; j--){
                cout<<color[i][j]<<" ";
            }
            cout<<color[i][1];
        }
        cout<<endl;
    }
    return 0;
}