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++ (GCC 9.2.1) (judge verdict: Accepted)

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <algorithm>
#include <climits>
#include <cmath>
#include <cstring>
#include <deque>
#include <forward_list>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;
typedef long long ll;
typedef pair<int, int> P;

const ll MOD = 1E+09 + 7;
const ll INF = 1E18;
const int MAX_H = 100;
const int MAX_N = MAX_H * MAX_H;

int H, W, N;

int A[MAX_N + 1];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> H >> W >> N;

    for (int i = 1; i <= N; i++) {
        cin >> A[i];
    }

    int c = 1;
    for (int i = 0; i < H; i++) {
        vector<int> v;
        int col = 0;
        while (true) {
            if (col + A[c] > W) {
                for (int j = 0; j < W - col; j++) {
                    v.push_back(c);
                }
                A[c] -= W - col;
                break;
            }
            col += A[c];
            for (int j = 0; j < A[c]; j++) {
                v.push_back(c);
            }
            c++;
        }
        if (i & 1) {
            for (auto ite = v.rbegin(); ite != v.rend(); ite++) {
                cout << *ite << " ";
            }
        } else {
            for (auto ite = v.begin(); ite != v.end(); ite++) {
                cout << *ite << " ";
            }
        }
        cout << "\n";
    }

    return 0;
}