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: Runtime Error)

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <unordered_set>
#include <stack>
#include <queue>
#include <math.h>
#include <string>
#include <numeric>
#include <algorithm>
#include <utility>

using namespace std;
typedef long long ll;
typedef unsigned long long ull;


// 68 11 55 - rank 3
// 69 12 19

int gcd(int a, int b) {
    while (b != 0) {
        auto na = a % b;
        a = b;
        b = na;
    }
    return a;
}


void oneCase() {
    int h, w, n;
    cin >> h >> w >> n;
    vector<int> a(n);
    for (auto& e : a) {
        cin >> e;
    }
    int color = 0;
    int id = 0;
    vector<vector<int>> b(h, vector<int>(w, 0));
    for (int r = 0; r < h; ++r) {
        for (int c = 0; c < w; ++c) {
            auto column = c;
            if (r % 2 == 1) {
                column = n - c - 1;
            }
            if (color == a[id]) {
                ++id;
                color = 0;
            }
            b[r][column] = id;
            ++color;
        }
    }

    for (auto& row : b) {
        for (auto el : row) {
            cout << el + 1<< " ";
        }
        cout << "\n";
    }
}


int main() {
    int t = 1;
//    cin >> t;
    while (t--) {
       oneCase();
    }

    return 0;
}

ll fact(ll n, ll mod) {
    ll res = 1;
    while (n > 0) {
        res = (res * n) % mod;
        --n;
    }
    return res;
}