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<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<algorithm>
#define N 200000
using namespace std;
typedef long long ll;
int h,w,n;
int c[N];
int col[200][200];
int main(){
	//freopen ("2.in","r",stdin);
	//freopen ("2.out","w",stdout);
	scanf ("%d%d%d",&h,&w,&n);
	int la=1,x;
	for (int i=1;i<=n;++i){
		scanf ("%d",&x);
		while (x--) c[la++]=i;
	}
	int cnt=1,i=0,j=1;
	while(cnt<=h*w){  
        while(i<h&&!col[i+1][j]) col[++i][j]=c[cnt++];
        while(j>1&&!col[i][j-1]) col[i][--j]=c[cnt++];
        while(i>1&&!col[i-1][j]) col[--i][j]=c[cnt++];
        while(j<w&&!col[i][j+1]) col[i][++j]=c[cnt++];
    }  
	for (int i=1;i<=h;++i){
		for (int j=1;j<=w;++j) cout<<col[i][j]<<" ";
		cout<<endl;
	}
	return 0;
}