SPOJ Problem Set (classical) 7191. Hexagonal Board Problem code: HEXBOARD

Square boards (as the chessboard) are really common among games and luckily, they are easy
to draw with the help of a ruler. However, there exist other games that requiere hexagonal
boards, that are much harder to draw by hand.
The Institute for Client Permanent Comfort (ICPC) of a famous board game factory has decided
to provide their customers with an automated program to build hexagonal boards for several
games. The size of an hexagonal board is determined by a single integer N that indicates how
many cells there are in each of the 6 sides of the board. For example, a board of size N = 2
should look as follows when drawn by the program.
      _
 _/ \_
/ \_/ \
\_/ \_/
/ \_/ \
\_/ \_/
  \_/
Your task is to help ICPC in making the program.

Input

The input contains several test cases. Each test case is described in a single line that contains
an integer N representing the size of the board (1 ≤ N ≤ 20). The last line of the input
contains a single −1 and should not be processed as a test case.

Output

For each test case output the hexagonal board of the required size, and a line with exactly
three asterisks. You have to follow the sample input and output, as well as the example given
above. Use only regular spaces, underscores (“ ”), slashes (“/”) and backslashes (“\”). There
must be no trailing spaces at the end of printed lines, neither empty lines.

Example

Input:
1
3
-1

Output:
 _
/ \
\_/
***
     _
   _/ \_
 _/ \_/ \_
/ \_/ \_/ \
\_/ \_/ \_/
/ \_/ \_/ \
\_/ \_/ \_/
/ \_/ \_/ \
\_/ \_/ \_/
  \_/ \_/
    \_/
***

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Added by:	Pablo Ariel Heiber
Date:	2010-08-19
Time limit:	1s
Source limit:	50000B
Languages:	All except: PERL 6
Resource:	FCEyN UBA ICPC Selection 2008