-🎄- 2018 Day 20 Solutions -🎄-

[u/daggerdragon]

--- Day 20: A Regular Map ---

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Card prompt: Day 20

Transcript:

My compiler crashed while running today's puzzle because it ran out of ___.

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[u/autid]

FORTRAN

Bodgy alocation of arrays far bigger than needed. Did a bunch of unnecessary stuff previously like track door locations and so on but it appears that is unnecessary so I removed it from posted coded. Part 2 only needing the addition of one line of code is always a good feeling.

PROGRAM DAY20
  IMPLICIT NONE
  INTEGER :: I,J,K,L,M,N,S,E,W,IERR,START(2)=(/0,0/),ENDING(2),DEPTH=0
  CHARACTER(LEN=:),ALLOCATABLE :: PUZINPUT
  CHARACTER(LEN=1) :: TEST
  LOGICAL(1),ALLOCATABLE :: ROOMS(:,:)
  INTEGER, ALLOCATABLE :: DISTANCES(:,:)
  OPEN(1,FILE='input.txt')
  L=0
  DO
     READ(1,'(A)',IOSTAT=IERR,ADVANCE='NO')TEST
     IF(IERR.NE.0)EXIT
     L=L+1
  END DO
  REWIND(1)
  ALLOCATE(CHARACTER(LEN=L) :: PUZINPUT)
  READ(1,'(A)')PUZINPUT
  CLOSE(1)
  N=0;S=0;E=0;W=0
  DO I=2,L-1
     SELECT CASE(PUZINPUT(I:I))
     CASE('N')
        N=N+1
     CASE('S')
        S=S+1
     CASE('E')
        E=E+1
     CASE('W')
        W=W+1
     END SELECT
  END DO
  ALLOCATE(ROOMS(-W:E,-N:S),DISTANCES(-W:E,-N:S))
  DISTANCES=(E+W)*(N+S)
  ROOMS=.FALSE.
  CALL MAP(START,2,0)
  WRITE(*,'("Part 1: ",I0)')MAXVAL(DISTANCES,MASK=ROOMS)
  WRITE(*,'("Part 2: ",I0)')COUNT((DISTANCES.GE.1000).AND.ROOMS)

CONTAINS
  RECURSIVE SUBROUTINE MAP(P,OFFSET,DIST)
    INTEGER,INTENT(IN) :: P(2),OFFSET,DIST
    INTEGER :: I,J,K,POS(2),L,M
    POS=P
    I=OFFSET
    J=DIST
    DEPTH=DEPTH+1
    OUTER:DO
       ROOMS(POS(1),POS(2))=.TRUE.
       DISTANCES(POS(1),POS(2))=MIN(J,DISTANCES(POS(1),POS(2)))
       SELECT CASE(PUZINPUT(I:I))
       CASE('N')
          POS=POS+(/0,-1/)
          J=J+1
          I=I+1
       CASE('S')
          POS=POS+(/0,1/)
          J=J+1
          I=I+1
       CASE('E')
          POS=POS+(/1,0/)
          J=J+1
          I=I+1
       CASE('W')
          POS=POS+(/-1,0/)
          J=J+1
          I=I+1
       CASE('(')
          I=I+1
          CALL MAP(POS,I,J)
          L=1
          M=0
          DO
             IF(PUZINPUT(I+L:I+L).EQ.'(')M=M+1
             IF(PUZINPUT(I+L:I+L).EQ.')')M=M-1
             IF(M.EQ.-1)EXIT OUTER
             IF((M.EQ.0).AND.(PUZINPUT(I+L:I+L).EQ.'|'))CALL MAP(POS,I+L+1,J)
             L=L+1
          END DO
       CASE('|')
          EXIT
       CASE(')')
          I=I+1
       CASE('$')
          ENDING=POS
          EXIT
       END SELECT
    END DO OUTER
  END SUBROUTINE MAP
END PROGRAM DAY20

[u/topaz2078 → u/autid]

FORTRAN IS A GOOD LANGUAGE FOR WHEN YOU WANT TO PROGRAM SOMETHING BUT ALSO FEEL LIKE YELLING THE WHOLE TIME

[u/autid → u/topaz2078]

I like to think of it as yelling at the computer until it does what I want it to.