Day 12 part 2?

2023/Makefile

@@ -1,8 +1,8 @@
 FC:=gfortran
-FFLAGS:=-Wall -Wno-maybe-uninitialized
+FFLAGS:=-Wall -Wno-maybe-uninitialized -O2
 BIN:=./bin
 SRC:=./src
-BINS:=./bin/day01.bin ./bin/day01b.bin ./bin/day02.bin ./bin/day03.bin ./bin/day04.bin ./bin/day05.bin ./bin/day05b.bin ./bin/day06.bin ./bin/day07.bin ./bin/day07b.bin ./bin/day08.bin ./bin/day08b.bin ./bin/day09.bin ./bin/day10.bin ./bin/day11.bin
+BINS:=./bin/day01.bin ./bin/day01b.bin ./bin/day02.bin ./bin/day03.bin ./bin/day04.bin ./bin/day05.bin ./bin/day05b.bin ./bin/day06.bin ./bin/day07.bin ./bin/day07b.bin ./bin/day08.bin ./bin/day08b.bin ./bin/day09.bin ./bin/day10.bin ./bin/day11.bin ./bin/day12.bin
 
 all: aoc19
 

2023/data/day12ex1.txt

@@ -0,0 +1,7 @@
+???.### 1,1,3
+.??..??...?##. 1,1,3
+?#?#?#?#?#?#?#? 1,3,1,6
+????.#...#... 4,1,1
+????.######..#####. 1,6,5
+?###???????? 3,2,1
+

2023/src/day12.f90

@@ -0,0 +1,225 @@
+program day12
+    implicit none
+    integer, parameter :: max_chars = 300
+    integer, parameter :: max_rows = 2000
+    integer, parameter :: b_kind = selected_int_kind(15)
+    character(200) :: fname
+    character(max_chars) :: fline
+    character(max_chars) :: springs, spt
+    integer :: tn_spr, n_springs
+    integer :: n_arguments
+    integer :: n_repeats
+    integer :: istat
+    integer :: strlen
+    integer, allocatable :: tspec(:), specifiers(:)
+    integer :: tn_spec, n_specifiers
+    integer :: i, i2, i3
+    integer :: s_pos
+    integer :: num_wc
+    integer(kind=b_kind) :: val, total_valid
+
+    n_arguments = command_argument_count()
+    if (n_arguments .eq. 2) then
+        call get_command_argument(1, fname)
+        print *, "File: ", trim(fname)
+        call get_command_argument(2, fline)
+        read(fline, *) n_repeats
+        print *, "Number of repeats: ", n_repeats
+    else
+        print *, "Wrong number of arguments: ", n_arguments
+        stop
+    end if
+    open(10, file=fname)
+    total_valid = 0
+    do i=1,max_rows
+        read(10, "(a)", iostat=istat) fline
+        strlen = len_trim(fline)
+        if ((strlen .eq. 0) .or. (is_iostat_end(istat))) then
+            exit
+        end if
+        s_pos = scan(fline, " ")
+        tn_spr = s_pos - 1
+        spt = fline(1:tn_spr)
+        tn_spec = 1
+        do i2 = s_pos+1, strlen
+            if (fline(i2:i2) .eq. ',') then
+                tn_spec = tn_spec + 1
+            end if
+        end do
+        n_specifiers = tn_spec * (1 + n_repeats)
+        allocate(tspec(1:tn_spec))
+        allocate(specifiers(1:n_specifiers))
+        read(fline((s_pos + 1):strlen), *) tspec
+        do i2=0,n_repeats
+            do i3=1,tn_spec
+                specifiers(i2 * tn_spec + i3) = tspec(i3)
+            end do
+        end do
+        springs = spt
+        if (n_repeats .ge. 1) then
+            do i2=1,n_repeats
+                springs = trim(springs) // '?' // trim(spt)
+            end do
+        end if
+        n_springs = (n_repeats + 1) * tn_spr + n_repeats
+
+        print *, "Row: ", i
+        print *, "Original: ", trim(spt)
+        print *, "Original specifiers: "
+        print "(20i2)", tspec
+        print *, "Expanded: ", trim(springs)
+        print *, "Expanded specifiers: "
+        print "(20i2)", specifiers
+        num_wc = numstr(trim(springs), '?')
+        print *, "Length: ", n_springs
+        print *, "Number of wildcards: ", num_wc
+        val = nvalid(springs, n_springs, specifiers, n_specifiers, .true.)
+        print *, "Valid: ", val
+        print *
+        total_valid = total_valid + val
+        deallocate(tspec)
+        deallocate(specifiers)
+    end do
+    close(10)
+    print *
+    print *, "Total valid: ", total_valid
+
+    contains
+        function consistent(springs, n_spr, specs, n_specs)
+            implicit none
+            character(*), intent(in) ::springs
+            integer, intent(in) :: specs(:)
+            integer, intent(in) :: n_spr, n_specs
+            logical :: consistent
+            integer :: c1, c2, c3, i, speccur, clen
+
+            consistent = .true.
+            c1 = 1
+            speccur = 0
+            do i = 1, n_spr
+                if (c1 .gt. n_spr) then
+                    consistent = speccur .eq. n_specs
+                    ! We've run out of springs
+                    return
+                end if
+                c2 = scan(springs(c1:n_spr), '#')
+                if (c2 .eq. 0) then
+                    consistent = speccur .eq. n_specs
+                    ! Also run out of springs
+                    return
+                end if
+                c2 = c1 + c2 - 1
+                c3 = verify(springs(c2:n_spr), '#')
+                if (c3 .eq. 0) then
+                    ! Ends at end of string
+                    c3 = n_spr
+                else
+                    c3 = c2 + c3 - 2
+                end if
+                speccur = speccur + 1
+                if (speccur .gt. n_specs) then
+                    consistent = .false.
+                    return
+                end if
+                clen = c3 - c2 + 1
+                if (clen .ne. specs(speccur)) then
+                    consistent = .false.
+                    return
+                end if
+                c1 = c3 + 1
+            end do
+            print *, '???'
+        end function consistent
+
+        function numstr(springs, str)
+            implicit none
+            character(*), intent(in) :: springs, str
+            integer :: numstr
+            integer :: sprlen, i
+            sprlen = len_trim(springs)
+            numstr = 0
+            do i=1,sprlen
+                if (scan(springs(i:i), str) .ne. 0) then
+                    numstr = numstr + 1
+                end if
+            end do
+        end function numstr
+
+        function viable(springs, n_spr, specs, n_specs)
+            implicit none
+            character(*), intent(in) ::springs
+            integer, intent(in) :: specs(:)
+            integer, intent(in) :: n_spr, n_specs
+            logical :: viable
+            character(len=1) :: ch
+            integer :: i, i2, spi, spc, nrq, remt
+            logical :: ch1v, ch2v
+            spi = 0
+            spc = 0
+            viable = .true.
+            ch2v = .false.
+            do i=1,n_spr
+                ch1v = ch2v
+                ch = springs(i:i)
+                if (ch .eq. '?') then
+                    nrq = numstr(springs(i:n_spr), '?#')
+                    remt = 0
+                    do i2=spi,n_specs
+                        remt = remt + specs(i2)
+                    end do
+                    remt = remt - spc
+                    viable = (nrq .ge. remt)
+                    return
+                end if
+                ch2v = scan(ch, '#') .ne. 0
+                if (ch2v) then
+                    if (ch1v) then
+                        spc = spc + 1
+                        if (spc .gt. specs(spi)) then
+                            viable = .false.
+                            return
+                        end if
+                    else
+                        spc = 1
+                        spi = spi + 1
+                        if (spi .gt. n_specs) then
+                            viable = .false.
+                            return
+                        end if
+                    end if
+                end if
+            end do
+        end function viable
+
+        recursive function nvalid(springs, n_spr, specs, n_specs, r_branch) result(nv)
+            implicit none
+            character(len=max_chars), intent(in) ::springs
+            integer, intent(in) :: specs(:)
+            integer, intent(in) :: n_spr, n_specs
+            logical, intent(in) :: r_branch
+            integer :: nv
+            integer :: s_pos
+            character(len=max_chars) :: test_spr
+            nv = 0
+            s_pos = scan(springs, '?')
+            if (r_branch) then
+                print *, "Right branch depth: ", s_pos
+            end if
+            if (s_pos .eq. 0) then
+                if (consistent(springs, n_spr, specs, n_specs)) then
+                    nv = nv + 1
+                end if
+                return
+            end if
+            test_spr = springs
+            test_spr(s_pos:s_pos) = '#'
+            if (viable(test_spr, n_spr, specs, n_specs)) then
+                nv = nv + nvalid(test_spr, n_spr, specs, n_specs, .false.)
+            end if
+            test_spr(s_pos:s_pos) = '.'
+            if (viable(test_spr, n_spr, specs, n_specs)) then
+                nv = nv + nvalid(test_spr, n_spr, specs, n_specs, r_branch)
+            end if
+        end function nvalid
+end program day12
+