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)

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdlib>
#include <vector>
#include <queue>
#include <set>
#include <map>
using namespace std;
int hw[101][101],h,w,tl,a[101],n,x;
void fg(int r,int c){
    int r1=r,c1=c;
    //cout<<'~'<<a[x]<<endl;
    while(a[x]--){
        //cout<<r1<<' '<<c1<<':'<<hw[r1][c1]<<endl;
        if(hw[r1][c1]!=0){r1++;c1=c;}
        hw[r1][c1]=x+1;
        c1++;if(c1>=min(w,100)||hw[r1][c1]!=0){c1--;r1++;}
        if(r1>=min(h,100)){r1=r+1;c1--;}
    }
}
int main(){
   	while(cin>>h>>w>>n){
        memset(hw,0,sizeof(hw));tl=h*w;x=0;
        for(int i=0;i<n;i++)cin>>a[i];
        for(int i=0;i<tl&&x<n;i++){

            if(hw[i/w][i%w]==0){
                //cout<<i/w<<' '<<i%w<<' '<<hw[i/h][i%h]<<' '<<x<<' '<<a[x]<<endl;
                fg(i/w,i%w);x++;
            }
        }
        for(int i=0;i<h;i++){
            cout<<hw[i][0];
            for(int j=1;j<w;j++){cout<<' '<<hw[i][j];}
            cout<<endl;
        }
   	}
    return 0;
}