My yearly advent-of-code solutions
treybastian.com
1program day_04
2 implicit none
3 character(len=140) :: lines(140)
4 character(len=1) :: c
5 integer :: io, row, col, score, z
6 logical :: left_m, right_m
7
8 left_m = .false.
9 right_m = .false.
10 score = 0
11 open(newunit=io, file='./day_04_input.txt', status='old', action='read')
12 read(io, '(a)') lines
13 do row = 2, size(lines) - 1
14 do col = 2, len(lines(row)) - 1
15 if (lines(row)(col:col) == 'A') then
16 c = lines(row-1)(col-1:col-1)
17 if (c == 'S' .or. c == 'M') then
18 left_m = c == 'M'
19 c = lines(row-1)(col+1:col+1)
20 if (c == 'S' .or. c == 'M') then
21 right_m = c == 'M'
22 c = lines(row+1)(col-1:col-1)
23 if (right_m .and. c == 'S' .or. (.not. right_m .and. c == 'M')) then
24 c = lines(row+1)(col+1:col+1)
25 if (left_m .and. c == 'S' .or. (.not. left_m .and. c =='M')) then
26 score = score + 1
27 end if
28 end if
29 end if
30 end if
31 end if
32 left_m = .false.
33 right_m = .false.
34 c = ''
35 end do
36 end do
37 print*, score
38
39end program day_04