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 <math.h>
#include <string>
#include <algorithm>
using namespace std;
int kaijo(int n){
	int ans = 1;
	if (n != 0){
		for (int i = 0; i < n; i++){
			ans *= (n - i);
		}
	}
	else{
		ans = 1;
	}
	return ans;
}

int main(){
	int a[10000];
	string s="";
	int cnt = 1;
	int cnt2 = 0;
	int b;
	int c = 1;
	int q;
	int m = 0;
	int flag = 0;
	int h,w;
	cin >> h;
	cin >> w;
	int n;
	cin >> n;
	for (int i = 0; i < n; i++){
		cin >> a[i];
	}
	//for (int i1 = 0; i1 < w; i1++){
	q = a[0];
	while (1){
		
		if (c>n){
			break;
		}
		
		q = q-m;
		//cout << q <<"あ"<< endl;
		b = cnt2 / 2;
		if (b * 2 == cnt2){
			for (int i2 = 0; i2 < q; i2++){
				if (cnt == w) {
					cout << c << endl;
					flag = 1;
					cnt = 1;
					m = i2 + 1;
					cnt2++;
					break;
				}
				else{
					cout << c<<" ";
					cnt++;
				}
			}
		}
		else{
			for (int i2 = 0; i2 < q; i2++){
				if (cnt == w) {
					//cout << c << endl;
					s = to_string(c)+" " + s;
					s.pop_back();
					cout << s << endl;
					flag = 1;
					cnt = 1;
					m = i2 + 1;
					cnt2++;
					s = "";
					break;
				}
				else{
					//cout << c;
					s = to_string(c)+" " + s;
					cnt++;
				}
			}
		}
		if (flag == 0){
			c++;
			m = 0;
			q = a[c - 1];
			//cnt = 1;
		}
		flag = 0;
		
		
	}
	//cout << c << endl;
	//}
	return 0;
}