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"
#define int long long
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=(a);i<(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define itr(i,x) for(auto i=(x).begin();i!=(x).end();++i)
#define All(x) (x).begin(),(x).end()
using namespace std;
typedef pair<int,int> P;
const int mod=1000000007;
int gcd(int x,int y){return y?gcd(y,x%y):x;}
int lcm(int x,int y){return x*y/gcd(x,y);}

signed main(){
	int H,W,n;
	cin>>H>>W>>n;
	vector<int> a(n);
	vector<vector<int>> s(H,vector<int>(W));
	rep(i,n) cin>>a[i];
	int i=0;
	bool flag=true;
	rep(j,H*W){
		if(a[i]==0) i++;
		if(flag) s[j/W][j%W]=i+1;
		else s[j/W][W-1-j%W]=i+1;
		if(j%W==W-1) flag = (!flag);
		a[i]--;
	}
	rep(i,H) rep(j,W) cout<<s[i][j]<<" \n"[j==W-1];
}