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 <algorithm>
#include <string>
#include <vector>
#include <cmath>
#include <set>
#include <map>
#include <queue>
using namespace std;
#define rep(i,n) for(int i = 0;i<n;i++)
const long long MOD = 1000000007LL;
const string alpha = "abcdefghijklmnopqrstuvwxyz";
int main(){
    int h,w;
    cin >> h >> w;
    int n;
    cin >> n;
    int a[n];
    rep(i,n){
        cin >> a[i];
    }
    int ans[h][w];
    int cnt = 0;
    int jj = 0;
    int flag = 1;
    rep(i,h){
        while(jj>=0&&jj<w){
            if(a[cnt]==0) cnt++;
            ans[i][jj]=cnt+1;
            //cout << i << " " << jj << endl;
            a[cnt]--;
            jj+=flag;
        }
        flag*=(-1);
        if(jj==-1) jj=0;
        else jj = w-1;
    }
    rep(i,h){
        rep(j,w){
            cout << ans[i][j] << " ";
        }
        cout << endl;
    }
    cout << endl;
}