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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	sc.Scan()
	iv, _ := strconv.Atoi(sc.Text())
	return iv
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	h, w, n := scanInt(), scanInt(), scanInt()
	a := make([]int, n)
	for i := range a {
		a[i] = scanInt()
	}

	ans := make([][]int, h)
	for i := range ans {
		ans[i] = make([]int, w)
	}

	x, y, d := -1, 0, 1
	for i, v := range a {
		for j := 0; j < v; j++ {
			if d == 1 {
				x++
				if x == w {
					x--
					y++
					d = -1
				}
			} else {
				x--
				if x == -1 {
					x++
					y++
					d = 1
				}
			}
			ans[y][x] = i + 1
		}
	}

	var wr = bufio.NewWriter(os.Stdout)
	for i := range ans {
		for j := range ans[i] {
			wr.WriteString(strconv.Itoa(ans[i][j]))
			if j < len(ans[i])-1 {
				wr.WriteString(" ")
			} else {
				wr.WriteString("\n")
			}
		}
	}
	wr.Flush()
}