Re^4: The Perl 6 Coding Contest 2012

[moritz]

in reply to Re^3: The Perl 6 Coding Contest 2012
in thread The Perl 6 Coding Contest 2012

0 _      _ 3
   \    /   
1 _ \  / _ 4
   \ \/ /   
2 __\/\/__ 2
    /\/\    
3 _/ /\ \_ 0
    /  \    
4 _/    \_ 1

That's not an option. Crossing have to be pairwise, I.e if 0 crosses over to 1, 1 must also cross over to 0. So you have to wire it as

0 _____  _____ 3
       \/    
1 ___  /\  ___ 4
     \/  \/  
2 _  /\  /\  _ 2
   \/  \/  \/
3 _/\  /\  /\_ 0
     \/  \/  
4 ___/\__/\___ 1

Think of it as physical wires, and all you can do is to exchange two adjacent wires.

I'll point masak to this thread so he can object if I wrote something wrong.

[BrowserUk]

Crossing have to be pairwise,

Sorry, but that contradicts masak's second and third examples (I think!).

[moritz]

I don't see the contradiction.

Second example:

Input: 1234567890

Output:

0 _  _________________ 1
   \/
1 _/\  _______________ 2
     \/
2 ___/\  _____________ 3
       \/
3 _____/\  ___________ 4
         \/
4 _______/\  _________ 5
           \/
5 _________/\  _______ 6
             \/
6 ___________/\  _____ 7
               \/
7 _____________/\  ___ 8
                 \/
8 _______________/\  _ 9
                   \/
9 _________________/\_ 0

To make it clearer, I've added spaces between the layers:

0 _   __ __ __ __ __ __ __ ___ 1
   \/ 
1 _/\    __ __ __ __ __ __ ___ 2
      \/ 
2 ___ /\    __ __ __ __ __ ___ 3
         \/ 
3 ___ __ /\    __ __ __ __ ___ 4
            \/ 
4 ___ __ __ /\    __ __ __ ___ 5
               \/ 
5 ___ __ __ __ /\    __ __ ___ 6
                  \/ 
6 ___ __ __ __ __ /\    __ ___ 7
                     \/ 
7 ___ __ __ __ __ __ /\    ___ 8
                        \/ 
8 ___ __ __ __ __ __ __ /\   _ 9
                           \/
9 ___ __ __ __ __ __ __ __ /\_ 0

[BrowserUk]

Hm. I do not see any stated or implied restrictions on the input:

Write a program that, given a permutation of the digits 0..9, arranges crossings on a grid that places the wires in the order designated by the permutation.

I guess we'll need masak to clarify things.

[BrowserUk]

FWIW: The penny finally dropped. You are right.