My yearly advent-of-code solutions
treybastian.com
1module day2_utils
2 implicit none
3contains
4 subroutine is_safe(list, res)
5 implicit none
6 integer, allocatable, intent(in) :: list(:)
7 logical, intent(out):: res
8 integer :: i, diff
9 logical is_decrement
10
11 res = .true.
12 is_decrement = .false.
13 do i = 1, size(list) - 1
14 if(i == 1 .and. list(i) > list(i+1)) then
15 is_decrement = .true.
16 end if
17 diff = abs(list(i) - list(i+1))
18 if(is_decrement) then
19 if (list(i) < list(i+1) .or. diff > 3 .or. diff < 1) then
20 res = .false.
21 exit
22 end if
23 else
24 if (list(i) > list(i+1) .or. diff > 3 .or. diff < 1) then
25 res = .false.
26 exit
27 end if
28 end if
29 end do
30 end subroutine is_safe
31 subroutine safe_with_dampener(list, res)
32 implicit none
33 integer, allocatable, intent(in) :: list(:)
34 integer, allocatable :: work(:)
35 logical, intent(out):: res
36 integer :: i, x, idx
37 res = .true.
38 call is_safe(list, res)
39 if(.not. res) then
40 allocate(work(size(list)-1))
41 do i = 1, size(list)
42 idx = 1
43 do x = 1, size(list)
44 if (x /= i) then
45 work(idx) = list(x)
46 idx = idx + 1
47 end if
48 end do
49 res = .true.
50 call is_safe(work, res)
51 if(res) then
52 exit
53 end if
54 end do
55 end if
56 end subroutine safe_with_dampener
57end module day2_utils
58
59program day_02_part_2
60 use day2_utils
61 implicit none
62 logical :: is_decrement, safe
63 integer :: io, i, x, spaces, res
64 integer, dimension(:), allocatable :: list
65 character(len=100) :: line
66
67 open(newunit=io, file='./day_02_input.txt', status='old', action='read')
68
69 res = 0
70 do i = 1, 1000
71 read(io, '(a)') line ! reading the line
72 spaces = 1 ! reset space count
73 do x = 1, len(trim(line))
74 ! counting spaces to see how big of an array we need to allocate
75 if(iachar(line(x:x))== 32 ) then
76 spaces = spaces+1
77 end if
78 end do
79
80 allocate(list(spaces))
81 read(line, *) list !reading the ints into an array
82 safe = .true. !set fail to false by default
83 call safe_with_dampener(list, safe) ! check if the array has a fail idx
84 if (safe) then
85 res = res + 1
86 endif
87 deallocate(list)
88 end do
89 print*, res
90end program day_02_part_2