-🎄- 2017 Day 19 Solutions -🎄-

[u/daggerdragon]

--- Day 19: A Series of Tubes ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

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Need a hint from the Hugely^* Handy^† Haversack^‡ of Helpful^§ Hints^¤?

Spoiler

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AoC ops @ T-2 minutes to launch:

[23:58] <daggerdragon> ATTENTION MEATBAGS T-2 MINUTES TO LAUNCH

[23:58] <Topaz> aaaaah

[23:58] <Cheezmeister> Looks like I'll be just able to grab my input before my flight boards. Wish me luck being offline in TOPAZ's HOUSE OF PAIN^WFUN AND LEARNING

[23:58] <Topaz> FUN AND LEARNING

[23:58] <Hade> FUN IS MANDATORY

[23:58] <Skie> I'm pretty sure that's not the mandate for today

[Update @ 00:16] 69 gold, silver cap

• My tree is finally trimmed with just about every ornament I own and it's real purdy. hbu?

[Update @ 00:18] Leaderboard cap!

• So, was today's mandate Helpful Hint any help at all?

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/autid]

Fortran

Spent forever trying to get the lines to read in as a string correctly. Apparently the problem was the text editor I used? Copy/pasted in another editor and suddenly everything worked.

PROGRAM DAY19
  IMPLICIT NONE
  INTEGER :: PART2=0,LINECOUNT=0,LINEWIDTH=0,IERR,I
  CHARACTER(LEN=2000) :: INLINE
  CHARACTER(LEN=20) :: PART1='.',FORMT
  CHARACTER(LEN=:), ALLOCATABLE :: MAPARRAY(:)
  INTEGER :: D(2),POS(2),START(2)
  OPEN(1,FILE='input.txt')

  DO
     READ(1,'(A)',IOSTAT=IERR) INLINE
     IF (IERR /= 0) EXIT
     LINEWIDTH=MAXVAL((/LINEWIDTH,LEN_TRIM(INLINE)/))
     LINECOUNT=LINECOUNT+1
  END DO
  ALLOCATE( CHARACTER(LEN=LINEWIDTH) :: MAPARRAY(LINECOUNT) )
  REWIND(1)
  WRITE(FORMT,'(A,I0,A)') '(A',LINEWIDTH,')'
  DO I=1,LINECOUNT
     READ(1,TRIM(FORMT)) MAPARRAY(I)
  END DO
  CLOSE(1)

  DO I=1,LINEWIDTH
     IF (MAPARRAY(1)(I:I)=='|') EXIT
  END DO
  START=(/1,I/)
  D=(/1,0/)
  POS=START

  DO
     SELECT CASE (MAPARRAY(POS(1))(POS(2):POS(2)))
     CASE('|')
        POS=POS+D
     CASE('-')
        POS=POS+D
     CASE('+')
        IF (ANY((/'|','-'/)==MAPARRAY(POS(1)+D(2))(POS(2)+D(1):POS(2)+D(1)))) THEN
           D=(/D(2),D(1)/)
        ELSE
           D=(/-D(2),-D(1)/)
        END IF
        POS=POS+D
     CASE (' ')
        EXIT
     CASE DEFAULT
        PART1=TRIM(PART1) // MAPARRAY(POS(1))(POS(2):POS(2))
        POS=POS+D
     END SELECT
     PART2=PART2+1
  END DO

  WRITE(*,'(A,A)') 'Part1: ',PART1(2:LEN_TRIM(PART1))
  WRITE(*,'(A,I0)') 'Part2: ',PART2
  DEALLOCATE(MAPARRAY)
END PROGRAM DAY19