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: Wrong Answer)

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
#define max0(a,b,c) max(max(a,b),c)
#define min0(a,b,c) min(min(a,b),c)
#define ft first
#define sc second
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define all(v) (v).begin(),(v).end()
#define mod 1000000007
using namespace std;
using Graph = vector<vector<int>>;
typedef long long lint;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ldouble;
typedef vector<int> vec;
typedef vector<ll> lvec;
typedef vector<ull> ulvec;
typedef vector<double> dvec;
typedef vector<pair<int,int>> pvec;
typedef vector<pair<ll,ll>> plvec;
typedef vector<tuple<ll,ll,ll>> tvec;
typedef vector<string> svec;

const int MAX_N=10000;

int H,W;
int N;
int a[MAX_N+1];
int b[101][101];

void solve(){
    int x=0,y=0,k=0;
    sort(a,a+N);
    bool flag=true;
    while(true){
        b[y][x]=k+1;
        a[k]--;
        if(a[k]==0) k++;
        if(flag){    
            if(x==W-1){
                y++;
                flag=false;
            }else{
                x++;
            }
        }else{
            if(x==0){
                y++;
                flag=true;
            }else{
                x--;
            }
        }
        if(a[N-1]==0) break;
    }
    rep(i,H){
        rep(j,W) cout<<b[i][j]<<' ';
        cout<<endl;
    }
}

int main(){
    cin>>H>>W;
    cin>>N;
    rep(i,N) cin>>a[i];
    solve();
}