Roll the carpet












13












$begingroup$


This question is inspired by Kevin Cruijssen's question.



Now that the carpet is laid out, we want to roll it. Your task is to write a program that takes a string and returns a spiral made from this string (representing a rolled carpet viewed from the side).



The procedure for one step of rolling the carpet is the following. There is an example to illustrate what I mean. Notice that the example starts with a partially rolled carpet for better understanding:



ac
rpet



  • separate the "head" from the "tail" of the carpet: the head is what has been rolled so far, the tail is what remains to be rolled.


Head: ac   Tail:
rp et



  • Rotate the head 90°, clockwise.


Rotated head: ra   Tail (unchanged):
pc et



  • if the width of the new head (here 2) is less or equal than the length of the tail (here 2)


    • then, put it on top of the tail

    • else, the carpet (as it was at the begining of the step) was rolled




New carpet: ra
pc
et


Repeat the procedure as many times as needed.





Two examples showing all steps of the carpet rolling:



carpet

c
arpet

ac
rpet

ra
pc
et


0123456789

0
123456789

10
23456789

21
30
456789

432
501
6789




Some precisions:




  • You don't need to show all intermediate steps, only the rolled carpet (e.g. if you find a non-iterative way to compute the result, it's perfect). Also, you don't need to print any leading whitespace, in the examples above, I only show them to align stuff.

  • Input is a String, a list/array of char

  • Output is printed to stdout or to a file.

  • Input is nice: the length is at least 1 char, and at most a constant sufficiently small so that it doesn't cause problems, but you can't use that constant in your program; the content of the string is only nice characters ([a-zA-Z0-9]), encoding at your preference.

  • This is code-golf, so shortest answer in bytes wins. Don't let code-golf languages discourage you from posting answers with non-codegolfing languages. Try to come up with an as short as possible answer for 'any' programming language.


  • Default Loopholes are forbidden.

  • If possible, please add a link with a test for your code.

  • Also, add an explanation for your answer if you think it is needed.










share|improve this question











$endgroup$








  • 3




    $begingroup$
    Closely related
    $endgroup$
    – Giuseppe
    17 hours ago






  • 2




    $begingroup$
    Also this one: codegolf.stackexchange.com/questions/125966/…, but none include the termination check.
    $endgroup$
    – Bromind
    17 hours ago








  • 3




    $begingroup$
    Suggested test case: ProgrammingPuzzlesAndCodeGolf - the final tail length greater than 1 tripped me up.
    $endgroup$
    – Sok
    17 hours ago












  • $begingroup$
    Where is the head on the second carpet example, where nothing is rolled up?
    $endgroup$
    – Embodiment of Ignorance
    15 hours ago






  • 1




    $begingroup$
    I think you've swapped the words "head" and "tail" here: "if the width of the new head [...] is greater or equal than the length of the tail [...]".
    $endgroup$
    – Erik the Outgolfer
    9 hours ago
















13












$begingroup$


This question is inspired by Kevin Cruijssen's question.



Now that the carpet is laid out, we want to roll it. Your task is to write a program that takes a string and returns a spiral made from this string (representing a rolled carpet viewed from the side).



The procedure for one step of rolling the carpet is the following. There is an example to illustrate what I mean. Notice that the example starts with a partially rolled carpet for better understanding:



ac
rpet



  • separate the "head" from the "tail" of the carpet: the head is what has been rolled so far, the tail is what remains to be rolled.


Head: ac   Tail:
rp et



  • Rotate the head 90°, clockwise.


Rotated head: ra   Tail (unchanged):
pc et



  • if the width of the new head (here 2) is less or equal than the length of the tail (here 2)


    • then, put it on top of the tail

    • else, the carpet (as it was at the begining of the step) was rolled




New carpet: ra
pc
et


Repeat the procedure as many times as needed.





Two examples showing all steps of the carpet rolling:



carpet

c
arpet

ac
rpet

ra
pc
et


0123456789

0
123456789

10
23456789

21
30
456789

432
501
6789




Some precisions:




  • You don't need to show all intermediate steps, only the rolled carpet (e.g. if you find a non-iterative way to compute the result, it's perfect). Also, you don't need to print any leading whitespace, in the examples above, I only show them to align stuff.

  • Input is a String, a list/array of char

  • Output is printed to stdout or to a file.

  • Input is nice: the length is at least 1 char, and at most a constant sufficiently small so that it doesn't cause problems, but you can't use that constant in your program; the content of the string is only nice characters ([a-zA-Z0-9]), encoding at your preference.

  • This is code-golf, so shortest answer in bytes wins. Don't let code-golf languages discourage you from posting answers with non-codegolfing languages. Try to come up with an as short as possible answer for 'any' programming language.


  • Default Loopholes are forbidden.

  • If possible, please add a link with a test for your code.

  • Also, add an explanation for your answer if you think it is needed.










share|improve this question











$endgroup$








  • 3




    $begingroup$
    Closely related
    $endgroup$
    – Giuseppe
    17 hours ago






  • 2




    $begingroup$
    Also this one: codegolf.stackexchange.com/questions/125966/…, but none include the termination check.
    $endgroup$
    – Bromind
    17 hours ago








  • 3




    $begingroup$
    Suggested test case: ProgrammingPuzzlesAndCodeGolf - the final tail length greater than 1 tripped me up.
    $endgroup$
    – Sok
    17 hours ago












  • $begingroup$
    Where is the head on the second carpet example, where nothing is rolled up?
    $endgroup$
    – Embodiment of Ignorance
    15 hours ago






  • 1




    $begingroup$
    I think you've swapped the words "head" and "tail" here: "if the width of the new head [...] is greater or equal than the length of the tail [...]".
    $endgroup$
    – Erik the Outgolfer
    9 hours ago














13












13








13


4



$begingroup$


This question is inspired by Kevin Cruijssen's question.



Now that the carpet is laid out, we want to roll it. Your task is to write a program that takes a string and returns a spiral made from this string (representing a rolled carpet viewed from the side).



The procedure for one step of rolling the carpet is the following. There is an example to illustrate what I mean. Notice that the example starts with a partially rolled carpet for better understanding:



ac
rpet



  • separate the "head" from the "tail" of the carpet: the head is what has been rolled so far, the tail is what remains to be rolled.


Head: ac   Tail:
rp et



  • Rotate the head 90°, clockwise.


Rotated head: ra   Tail (unchanged):
pc et



  • if the width of the new head (here 2) is less or equal than the length of the tail (here 2)


    • then, put it on top of the tail

    • else, the carpet (as it was at the begining of the step) was rolled




New carpet: ra
pc
et


Repeat the procedure as many times as needed.





Two examples showing all steps of the carpet rolling:



carpet

c
arpet

ac
rpet

ra
pc
et


0123456789

0
123456789

10
23456789

21
30
456789

432
501
6789




Some precisions:




  • You don't need to show all intermediate steps, only the rolled carpet (e.g. if you find a non-iterative way to compute the result, it's perfect). Also, you don't need to print any leading whitespace, in the examples above, I only show them to align stuff.

  • Input is a String, a list/array of char

  • Output is printed to stdout or to a file.

  • Input is nice: the length is at least 1 char, and at most a constant sufficiently small so that it doesn't cause problems, but you can't use that constant in your program; the content of the string is only nice characters ([a-zA-Z0-9]), encoding at your preference.

  • This is code-golf, so shortest answer in bytes wins. Don't let code-golf languages discourage you from posting answers with non-codegolfing languages. Try to come up with an as short as possible answer for 'any' programming language.


  • Default Loopholes are forbidden.

  • If possible, please add a link with a test for your code.

  • Also, add an explanation for your answer if you think it is needed.










share|improve this question











$endgroup$




This question is inspired by Kevin Cruijssen's question.



Now that the carpet is laid out, we want to roll it. Your task is to write a program that takes a string and returns a spiral made from this string (representing a rolled carpet viewed from the side).



The procedure for one step of rolling the carpet is the following. There is an example to illustrate what I mean. Notice that the example starts with a partially rolled carpet for better understanding:



ac
rpet



  • separate the "head" from the "tail" of the carpet: the head is what has been rolled so far, the tail is what remains to be rolled.


Head: ac   Tail:
rp et



  • Rotate the head 90°, clockwise.


Rotated head: ra   Tail (unchanged):
pc et



  • if the width of the new head (here 2) is less or equal than the length of the tail (here 2)


    • then, put it on top of the tail

    • else, the carpet (as it was at the begining of the step) was rolled




New carpet: ra
pc
et


Repeat the procedure as many times as needed.





Two examples showing all steps of the carpet rolling:



carpet

c
arpet

ac
rpet

ra
pc
et


0123456789

0
123456789

10
23456789

21
30
456789

432
501
6789




Some precisions:




  • You don't need to show all intermediate steps, only the rolled carpet (e.g. if you find a non-iterative way to compute the result, it's perfect). Also, you don't need to print any leading whitespace, in the examples above, I only show them to align stuff.

  • Input is a String, a list/array of char

  • Output is printed to stdout or to a file.

  • Input is nice: the length is at least 1 char, and at most a constant sufficiently small so that it doesn't cause problems, but you can't use that constant in your program; the content of the string is only nice characters ([a-zA-Z0-9]), encoding at your preference.

  • This is code-golf, so shortest answer in bytes wins. Don't let code-golf languages discourage you from posting answers with non-codegolfing languages. Try to come up with an as short as possible answer for 'any' programming language.


  • Default Loopholes are forbidden.

  • If possible, please add a link with a test for your code.

  • Also, add an explanation for your answer if you think it is needed.







code-golf string






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 9 hours ago







Bromind

















asked 17 hours ago









BromindBromind

1866




1866








  • 3




    $begingroup$
    Closely related
    $endgroup$
    – Giuseppe
    17 hours ago






  • 2




    $begingroup$
    Also this one: codegolf.stackexchange.com/questions/125966/…, but none include the termination check.
    $endgroup$
    – Bromind
    17 hours ago








  • 3




    $begingroup$
    Suggested test case: ProgrammingPuzzlesAndCodeGolf - the final tail length greater than 1 tripped me up.
    $endgroup$
    – Sok
    17 hours ago












  • $begingroup$
    Where is the head on the second carpet example, where nothing is rolled up?
    $endgroup$
    – Embodiment of Ignorance
    15 hours ago






  • 1




    $begingroup$
    I think you've swapped the words "head" and "tail" here: "if the width of the new head [...] is greater or equal than the length of the tail [...]".
    $endgroup$
    – Erik the Outgolfer
    9 hours ago














  • 3




    $begingroup$
    Closely related
    $endgroup$
    – Giuseppe
    17 hours ago






  • 2




    $begingroup$
    Also this one: codegolf.stackexchange.com/questions/125966/…, but none include the termination check.
    $endgroup$
    – Bromind
    17 hours ago








  • 3




    $begingroup$
    Suggested test case: ProgrammingPuzzlesAndCodeGolf - the final tail length greater than 1 tripped me up.
    $endgroup$
    – Sok
    17 hours ago












  • $begingroup$
    Where is the head on the second carpet example, where nothing is rolled up?
    $endgroup$
    – Embodiment of Ignorance
    15 hours ago






  • 1




    $begingroup$
    I think you've swapped the words "head" and "tail" here: "if the width of the new head [...] is greater or equal than the length of the tail [...]".
    $endgroup$
    – Erik the Outgolfer
    9 hours ago








3




3




$begingroup$
Closely related
$endgroup$
– Giuseppe
17 hours ago




$begingroup$
Closely related
$endgroup$
– Giuseppe
17 hours ago




2




2




$begingroup$
Also this one: codegolf.stackexchange.com/questions/125966/…, but none include the termination check.
$endgroup$
– Bromind
17 hours ago






$begingroup$
Also this one: codegolf.stackexchange.com/questions/125966/…, but none include the termination check.
$endgroup$
– Bromind
17 hours ago






3




3




$begingroup$
Suggested test case: ProgrammingPuzzlesAndCodeGolf - the final tail length greater than 1 tripped me up.
$endgroup$
– Sok
17 hours ago






$begingroup$
Suggested test case: ProgrammingPuzzlesAndCodeGolf - the final tail length greater than 1 tripped me up.
$endgroup$
– Sok
17 hours ago














$begingroup$
Where is the head on the second carpet example, where nothing is rolled up?
$endgroup$
– Embodiment of Ignorance
15 hours ago




$begingroup$
Where is the head on the second carpet example, where nothing is rolled up?
$endgroup$
– Embodiment of Ignorance
15 hours ago




1




1




$begingroup$
I think you've swapped the words "head" and "tail" here: "if the width of the new head [...] is greater or equal than the length of the tail [...]".
$endgroup$
– Erik the Outgolfer
9 hours ago




$begingroup$
I think you've swapped the words "head" and "tail" here: "if the width of the new head [...] is greater or equal than the length of the tail [...]".
$endgroup$
– Erik the Outgolfer
9 hours ago










4 Answers
4






active

oldest

votes


















2












$begingroup$

Pyth, 37 bytes



.U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQt


Try it online here, or verify all the test cases at once here.



.U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQtQ   Implicit: Q=eval(input())
Trailing Q inferred
]hQ First character of Q, wrapped in an array
tQ All but the first character of Q
, 2-element array of the two previous results
This yields array with rolled carpet (as array of strings) followed by the tail
.W While condition function is truthy, execute inner function, with initial value of the above:
gleHJlhH Condition function, input H
JlhH Number of layers in the current rolled carpet, store in J
leH Lenth of the tail
g J Is the above greater than or equal to J?
,+_MChZ<eZJ>eZJ Inner function, input Z
_MChZ Rotate the current rolled carpet (transpose, then reverse each row)
+ <eZJ Append the first J characters of the tail as a new row
, Pair the above with...
>eZJ ... all but the first J characters of the tail - this is the new tail
.U+j;bZ Join the carpet roll on newlines and append the tail, implicit print





share|improve this answer











$endgroup$





















    2












    $begingroup$


    J, 73 bytes



    [:(}:@[,{:@[,])&>/[:((|:@|.@[,#@[{.]);#@[}.])&>/^:(<:&#&>/)^:_,:@,:@{.;}.


    Try it online!



    I plan to golf this further after work tonight.






    share|improve this answer









    $endgroup$





















      1












      $begingroup$


      R, 146 132 bytes





      function(s){m=F[F]
      while({m=rbind(t(m)[,F:0],s[1:F])
      s=s[-1:-F]
      length(s)>sum(F<-dim(m))})0
      write(m[F:1,],1,F[1],,"")
      cat(s,sep="")}


      Try it online!



      Implements the carpet-rolling procedure. Takes input as a list of characters and prints to stdout.



      Saved 14 bytes by finding a way to use a do-while loop and initializing using F.



      function(s){
      m=F[F] # logical(0); create an empty array (this gets automatically promoted to character(0) later
      while( # do-while loop
      {m=rbind(t(m)[,F:0],s[1:F]) # rotate m counterclockwise and add the first F characters of s to the bottom
      s=s[-1:-F] # remove those characters
      length(s)>sum(F<-dim(m))})0 # while the number of characters remaining is greater than the sum of m's dimensions
      write(m[F:1,],1,F[1],,"") # write the rolled portion write writes down the columns, we reverse each column
      cat(s,sep="") # and write the remaining characters
      }





      share|improve this answer











      $endgroup$





















        1












        $begingroup$


        Jelly, 30 bytes



        Seems overly long...



        ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ


        Try it online!



        How?



        ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ - Main Link: list of characters
        Ḣ - pop and yield head
        W - wrap in a list
        , - pair with (the remaining list after Ḣ)
        ¿ - while...
        $ - ...condition: last two links as a monad:
        Ẉ - length of each
        Ƒ - is invariant under:
        Ṣ - sort
        / - ...do: reduce by:
        ð ð - the enclosed dyadic chain -- i.e. f(head, tail):
        Z - transpose
        U - reverse each (giving a rotated head)
        ɗ - last three links as a dyad:
        ¥ - last two links as a dyad:
        L - length (i.e. number of rows in current roll)
        @ - with swapped arguments:
        s - split (the tail) into chunks of that length
        © - (copy to register for later)
        Ḣ - pop and yield head (Note register "copy" is altered too)
        W - wrap in a list
        ; - concatenate (the rotated head with the first chunk of the tail)
        ¤ - nilad followed by link(s) as a nilad:
        ® - recall from register (other chunks of tail, or an empty list)
        Ẏ - tighten (the chunks to a flat list)
        , - pair (the concatenate result with the tightened chunks)
        Ɗ - last three links as a monad:
        Ḣ - pop and yield head
        Y - join with newline characters
        ; - concatenate (the remaining tail)
        - when running as a full program implicitly prints





        share|improve this answer









        $endgroup$














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          4 Answers
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          4 Answers
          4






          active

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          active

          oldest

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          2












          $begingroup$

          Pyth, 37 bytes



          .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQt


          Try it online here, or verify all the test cases at once here.



          .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQtQ   Implicit: Q=eval(input())
          Trailing Q inferred
          ]hQ First character of Q, wrapped in an array
          tQ All but the first character of Q
          , 2-element array of the two previous results
          This yields array with rolled carpet (as array of strings) followed by the tail
          .W While condition function is truthy, execute inner function, with initial value of the above:
          gleHJlhH Condition function, input H
          JlhH Number of layers in the current rolled carpet, store in J
          leH Lenth of the tail
          g J Is the above greater than or equal to J?
          ,+_MChZ<eZJ>eZJ Inner function, input Z
          _MChZ Rotate the current rolled carpet (transpose, then reverse each row)
          + <eZJ Append the first J characters of the tail as a new row
          , Pair the above with...
          >eZJ ... all but the first J characters of the tail - this is the new tail
          .U+j;bZ Join the carpet roll on newlines and append the tail, implicit print





          share|improve this answer











          $endgroup$


















            2












            $begingroup$

            Pyth, 37 bytes



            .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQt


            Try it online here, or verify all the test cases at once here.



            .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQtQ   Implicit: Q=eval(input())
            Trailing Q inferred
            ]hQ First character of Q, wrapped in an array
            tQ All but the first character of Q
            , 2-element array of the two previous results
            This yields array with rolled carpet (as array of strings) followed by the tail
            .W While condition function is truthy, execute inner function, with initial value of the above:
            gleHJlhH Condition function, input H
            JlhH Number of layers in the current rolled carpet, store in J
            leH Lenth of the tail
            g J Is the above greater than or equal to J?
            ,+_MChZ<eZJ>eZJ Inner function, input Z
            _MChZ Rotate the current rolled carpet (transpose, then reverse each row)
            + <eZJ Append the first J characters of the tail as a new row
            , Pair the above with...
            >eZJ ... all but the first J characters of the tail - this is the new tail
            .U+j;bZ Join the carpet roll on newlines and append the tail, implicit print





            share|improve this answer











            $endgroup$
















              2












              2








              2





              $begingroup$

              Pyth, 37 bytes



              .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQt


              Try it online here, or verify all the test cases at once here.



              .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQtQ   Implicit: Q=eval(input())
              Trailing Q inferred
              ]hQ First character of Q, wrapped in an array
              tQ All but the first character of Q
              , 2-element array of the two previous results
              This yields array with rolled carpet (as array of strings) followed by the tail
              .W While condition function is truthy, execute inner function, with initial value of the above:
              gleHJlhH Condition function, input H
              JlhH Number of layers in the current rolled carpet, store in J
              leH Lenth of the tail
              g J Is the above greater than or equal to J?
              ,+_MChZ<eZJ>eZJ Inner function, input Z
              _MChZ Rotate the current rolled carpet (transpose, then reverse each row)
              + <eZJ Append the first J characters of the tail as a new row
              , Pair the above with...
              >eZJ ... all but the first J characters of the tail - this is the new tail
              .U+j;bZ Join the carpet roll on newlines and append the tail, implicit print





              share|improve this answer











              $endgroup$



              Pyth, 37 bytes



              .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQt


              Try it online here, or verify all the test cases at once here.



              .U+j;bZ.WgleHJlhH,+_MChZ<eZJ>eZJ,]hQtQ   Implicit: Q=eval(input())
              Trailing Q inferred
              ]hQ First character of Q, wrapped in an array
              tQ All but the first character of Q
              , 2-element array of the two previous results
              This yields array with rolled carpet (as array of strings) followed by the tail
              .W While condition function is truthy, execute inner function, with initial value of the above:
              gleHJlhH Condition function, input H
              JlhH Number of layers in the current rolled carpet, store in J
              leH Lenth of the tail
              g J Is the above greater than or equal to J?
              ,+_MChZ<eZJ>eZJ Inner function, input Z
              _MChZ Rotate the current rolled carpet (transpose, then reverse each row)
              + <eZJ Append the first J characters of the tail as a new row
              , Pair the above with...
              >eZJ ... all but the first J characters of the tail - this is the new tail
              .U+j;bZ Join the carpet roll on newlines and append the tail, implicit print






              share|improve this answer














              share|improve this answer



              share|improve this answer








              edited 16 hours ago

























              answered 17 hours ago









              SokSok

              4,177925




              4,177925























                  2












                  $begingroup$


                  J, 73 bytes



                  [:(}:@[,{:@[,])&>/[:((|:@|.@[,#@[{.]);#@[}.])&>/^:(<:&#&>/)^:_,:@,:@{.;}.


                  Try it online!



                  I plan to golf this further after work tonight.






                  share|improve this answer









                  $endgroup$


















                    2












                    $begingroup$


                    J, 73 bytes



                    [:(}:@[,{:@[,])&>/[:((|:@|.@[,#@[{.]);#@[}.])&>/^:(<:&#&>/)^:_,:@,:@{.;}.


                    Try it online!



                    I plan to golf this further after work tonight.






                    share|improve this answer









                    $endgroup$
















                      2












                      2








                      2





                      $begingroup$


                      J, 73 bytes



                      [:(}:@[,{:@[,])&>/[:((|:@|.@[,#@[{.]);#@[}.])&>/^:(<:&#&>/)^:_,:@,:@{.;}.


                      Try it online!



                      I plan to golf this further after work tonight.






                      share|improve this answer









                      $endgroup$




                      J, 73 bytes



                      [:(}:@[,{:@[,])&>/[:((|:@|.@[,#@[{.]);#@[}.])&>/^:(<:&#&>/)^:_,:@,:@{.;}.


                      Try it online!



                      I plan to golf this further after work tonight.







                      share|improve this answer












                      share|improve this answer



                      share|improve this answer










                      answered 13 hours ago









                      JonahJonah

                      2,5611017




                      2,5611017























                          1












                          $begingroup$


                          R, 146 132 bytes





                          function(s){m=F[F]
                          while({m=rbind(t(m)[,F:0],s[1:F])
                          s=s[-1:-F]
                          length(s)>sum(F<-dim(m))})0
                          write(m[F:1,],1,F[1],,"")
                          cat(s,sep="")}


                          Try it online!



                          Implements the carpet-rolling procedure. Takes input as a list of characters and prints to stdout.



                          Saved 14 bytes by finding a way to use a do-while loop and initializing using F.



                          function(s){
                          m=F[F] # logical(0); create an empty array (this gets automatically promoted to character(0) later
                          while( # do-while loop
                          {m=rbind(t(m)[,F:0],s[1:F]) # rotate m counterclockwise and add the first F characters of s to the bottom
                          s=s[-1:-F] # remove those characters
                          length(s)>sum(F<-dim(m))})0 # while the number of characters remaining is greater than the sum of m's dimensions
                          write(m[F:1,],1,F[1],,"") # write the rolled portion write writes down the columns, we reverse each column
                          cat(s,sep="") # and write the remaining characters
                          }





                          share|improve this answer











                          $endgroup$


















                            1












                            $begingroup$


                            R, 146 132 bytes





                            function(s){m=F[F]
                            while({m=rbind(t(m)[,F:0],s[1:F])
                            s=s[-1:-F]
                            length(s)>sum(F<-dim(m))})0
                            write(m[F:1,],1,F[1],,"")
                            cat(s,sep="")}


                            Try it online!



                            Implements the carpet-rolling procedure. Takes input as a list of characters and prints to stdout.



                            Saved 14 bytes by finding a way to use a do-while loop and initializing using F.



                            function(s){
                            m=F[F] # logical(0); create an empty array (this gets automatically promoted to character(0) later
                            while( # do-while loop
                            {m=rbind(t(m)[,F:0],s[1:F]) # rotate m counterclockwise and add the first F characters of s to the bottom
                            s=s[-1:-F] # remove those characters
                            length(s)>sum(F<-dim(m))})0 # while the number of characters remaining is greater than the sum of m's dimensions
                            write(m[F:1,],1,F[1],,"") # write the rolled portion write writes down the columns, we reverse each column
                            cat(s,sep="") # and write the remaining characters
                            }





                            share|improve this answer











                            $endgroup$
















                              1












                              1








                              1





                              $begingroup$


                              R, 146 132 bytes





                              function(s){m=F[F]
                              while({m=rbind(t(m)[,F:0],s[1:F])
                              s=s[-1:-F]
                              length(s)>sum(F<-dim(m))})0
                              write(m[F:1,],1,F[1],,"")
                              cat(s,sep="")}


                              Try it online!



                              Implements the carpet-rolling procedure. Takes input as a list of characters and prints to stdout.



                              Saved 14 bytes by finding a way to use a do-while loop and initializing using F.



                              function(s){
                              m=F[F] # logical(0); create an empty array (this gets automatically promoted to character(0) later
                              while( # do-while loop
                              {m=rbind(t(m)[,F:0],s[1:F]) # rotate m counterclockwise and add the first F characters of s to the bottom
                              s=s[-1:-F] # remove those characters
                              length(s)>sum(F<-dim(m))})0 # while the number of characters remaining is greater than the sum of m's dimensions
                              write(m[F:1,],1,F[1],,"") # write the rolled portion write writes down the columns, we reverse each column
                              cat(s,sep="") # and write the remaining characters
                              }





                              share|improve this answer











                              $endgroup$




                              R, 146 132 bytes





                              function(s){m=F[F]
                              while({m=rbind(t(m)[,F:0],s[1:F])
                              s=s[-1:-F]
                              length(s)>sum(F<-dim(m))})0
                              write(m[F:1,],1,F[1],,"")
                              cat(s,sep="")}


                              Try it online!



                              Implements the carpet-rolling procedure. Takes input as a list of characters and prints to stdout.



                              Saved 14 bytes by finding a way to use a do-while loop and initializing using F.



                              function(s){
                              m=F[F] # logical(0); create an empty array (this gets automatically promoted to character(0) later
                              while( # do-while loop
                              {m=rbind(t(m)[,F:0],s[1:F]) # rotate m counterclockwise and add the first F characters of s to the bottom
                              s=s[-1:-F] # remove those characters
                              length(s)>sum(F<-dim(m))})0 # while the number of characters remaining is greater than the sum of m's dimensions
                              write(m[F:1,],1,F[1],,"") # write the rolled portion write writes down the columns, we reverse each column
                              cat(s,sep="") # and write the remaining characters
                              }






                              share|improve this answer














                              share|improve this answer



                              share|improve this answer








                              edited 16 hours ago

























                              answered 17 hours ago









                              GiuseppeGiuseppe

                              17.6k31152




                              17.6k31152























                                  1












                                  $begingroup$


                                  Jelly, 30 bytes



                                  Seems overly long...



                                  ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ


                                  Try it online!



                                  How?



                                  ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ - Main Link: list of characters
                                  Ḣ - pop and yield head
                                  W - wrap in a list
                                  , - pair with (the remaining list after Ḣ)
                                  ¿ - while...
                                  $ - ...condition: last two links as a monad:
                                  Ẉ - length of each
                                  Ƒ - is invariant under:
                                  Ṣ - sort
                                  / - ...do: reduce by:
                                  ð ð - the enclosed dyadic chain -- i.e. f(head, tail):
                                  Z - transpose
                                  U - reverse each (giving a rotated head)
                                  ɗ - last three links as a dyad:
                                  ¥ - last two links as a dyad:
                                  L - length (i.e. number of rows in current roll)
                                  @ - with swapped arguments:
                                  s - split (the tail) into chunks of that length
                                  © - (copy to register for later)
                                  Ḣ - pop and yield head (Note register "copy" is altered too)
                                  W - wrap in a list
                                  ; - concatenate (the rotated head with the first chunk of the tail)
                                  ¤ - nilad followed by link(s) as a nilad:
                                  ® - recall from register (other chunks of tail, or an empty list)
                                  Ẏ - tighten (the chunks to a flat list)
                                  , - pair (the concatenate result with the tightened chunks)
                                  Ɗ - last three links as a monad:
                                  Ḣ - pop and yield head
                                  Y - join with newline characters
                                  ; - concatenate (the remaining tail)
                                  - when running as a full program implicitly prints





                                  share|improve this answer









                                  $endgroup$


















                                    1












                                    $begingroup$


                                    Jelly, 30 bytes



                                    Seems overly long...



                                    ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ


                                    Try it online!



                                    How?



                                    ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ - Main Link: list of characters
                                    Ḣ - pop and yield head
                                    W - wrap in a list
                                    , - pair with (the remaining list after Ḣ)
                                    ¿ - while...
                                    $ - ...condition: last two links as a monad:
                                    Ẉ - length of each
                                    Ƒ - is invariant under:
                                    Ṣ - sort
                                    / - ...do: reduce by:
                                    ð ð - the enclosed dyadic chain -- i.e. f(head, tail):
                                    Z - transpose
                                    U - reverse each (giving a rotated head)
                                    ɗ - last three links as a dyad:
                                    ¥ - last two links as a dyad:
                                    L - length (i.e. number of rows in current roll)
                                    @ - with swapped arguments:
                                    s - split (the tail) into chunks of that length
                                    © - (copy to register for later)
                                    Ḣ - pop and yield head (Note register "copy" is altered too)
                                    W - wrap in a list
                                    ; - concatenate (the rotated head with the first chunk of the tail)
                                    ¤ - nilad followed by link(s) as a nilad:
                                    ® - recall from register (other chunks of tail, or an empty list)
                                    Ẏ - tighten (the chunks to a flat list)
                                    , - pair (the concatenate result with the tightened chunks)
                                    Ɗ - last three links as a monad:
                                    Ḣ - pop and yield head
                                    Y - join with newline characters
                                    ; - concatenate (the remaining tail)
                                    - when running as a full program implicitly prints





                                    share|improve this answer









                                    $endgroup$
















                                      1












                                      1








                                      1





                                      $begingroup$


                                      Jelly, 30 bytes



                                      Seems overly long...



                                      ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ


                                      Try it online!



                                      How?



                                      ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ - Main Link: list of characters
                                      Ḣ - pop and yield head
                                      W - wrap in a list
                                      , - pair with (the remaining list after Ḣ)
                                      ¿ - while...
                                      $ - ...condition: last two links as a monad:
                                      Ẉ - length of each
                                      Ƒ - is invariant under:
                                      Ṣ - sort
                                      / - ...do: reduce by:
                                      ð ð - the enclosed dyadic chain -- i.e. f(head, tail):
                                      Z - transpose
                                      U - reverse each (giving a rotated head)
                                      ɗ - last three links as a dyad:
                                      ¥ - last two links as a dyad:
                                      L - length (i.e. number of rows in current roll)
                                      @ - with swapped arguments:
                                      s - split (the tail) into chunks of that length
                                      © - (copy to register for later)
                                      Ḣ - pop and yield head (Note register "copy" is altered too)
                                      W - wrap in a list
                                      ; - concatenate (the rotated head with the first chunk of the tail)
                                      ¤ - nilad followed by link(s) as a nilad:
                                      ® - recall from register (other chunks of tail, or an empty list)
                                      Ẏ - tighten (the chunks to a flat list)
                                      , - pair (the concatenate result with the tightened chunks)
                                      Ɗ - last three links as a monad:
                                      Ḣ - pop and yield head
                                      Y - join with newline characters
                                      ; - concatenate (the remaining tail)
                                      - when running as a full program implicitly prints





                                      share|improve this answer









                                      $endgroup$




                                      Jelly, 30 bytes



                                      Seems overly long...



                                      ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ


                                      Try it online!



                                      How?



                                      ḢW,ðZU;Ls@¥©ḢWɗ,®Ẏ¤ð/ẈṢƑ$¿ḢY;Ɗ - Main Link: list of characters
                                      Ḣ - pop and yield head
                                      W - wrap in a list
                                      , - pair with (the remaining list after Ḣ)
                                      ¿ - while...
                                      $ - ...condition: last two links as a monad:
                                      Ẉ - length of each
                                      Ƒ - is invariant under:
                                      Ṣ - sort
                                      / - ...do: reduce by:
                                      ð ð - the enclosed dyadic chain -- i.e. f(head, tail):
                                      Z - transpose
                                      U - reverse each (giving a rotated head)
                                      ɗ - last three links as a dyad:
                                      ¥ - last two links as a dyad:
                                      L - length (i.e. number of rows in current roll)
                                      @ - with swapped arguments:
                                      s - split (the tail) into chunks of that length
                                      © - (copy to register for later)
                                      Ḣ - pop and yield head (Note register "copy" is altered too)
                                      W - wrap in a list
                                      ; - concatenate (the rotated head with the first chunk of the tail)
                                      ¤ - nilad followed by link(s) as a nilad:
                                      ® - recall from register (other chunks of tail, or an empty list)
                                      Ẏ - tighten (the chunks to a flat list)
                                      , - pair (the concatenate result with the tightened chunks)
                                      Ɗ - last three links as a monad:
                                      Ḣ - pop and yield head
                                      Y - join with newline characters
                                      ; - concatenate (the remaining tail)
                                      - when running as a full program implicitly prints






                                      share|improve this answer












                                      share|improve this answer



                                      share|improve this answer










                                      answered 12 hours ago









                                      Jonathan AllanJonathan Allan

                                      53.7k535173




                                      53.7k535173






























                                          draft saved

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                                          If this is an answer to a challenge…




                                          • …Be sure to follow the challenge specification. However, please refrain from exploiting obvious loopholes. Answers abusing any of the standard loopholes are considered invalid. If you think a specification is unclear or underspecified, comment on the question instead.


                                          • …Try to optimize your score. For instance, answers to code-golf challenges should attempt to be as short as possible. You can always include a readable version of the code in addition to the competitive one.
                                            Explanations of your answer make it more interesting to read and are very much encouraged.


                                          • …Include a short header which indicates the language(s) of your code and its score, as defined by the challenge.



                                          More generally…




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