diff options
Diffstat (limited to '2024')
| -rw-r--r-- | 2024/day_09.f90 | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/2024/day_09.f90 b/2024/day_09.f90 new file mode 100644 index 0000000..3cf8579 --- /dev/null +++ b/2024/day_09.f90 @@ -0,0 +1,142 @@ +module day_09_utils + implicit none +contains + subroutine swap_to_first_positive_integer_from_end(arr, idx) + implicit none + integer, allocatable, intent(inout) :: arr(:) + integer, intent(in) :: idx + integer, allocatable :: temp(:) + integer :: i, res + do i = 0, size(arr) - 1 + if(arr(size(arr) - i) > -1) then + arr(idx) = arr(size(arr) - i) + allocate(temp(size(arr) - (i +1))) + temp = arr(1:size(arr) - (i+1)) + call move_alloc(temp, arr) + return + end if + end do + end subroutine swap_to_first_positive_integer_from_end + subroutine append_to_integer_array_times(arr, val, times) + implicit none + integer, allocatable, intent(inout) :: arr(:) + integer, intent(in) :: val, times + integer, allocatable :: temp(:) + if(.not. allocated(arr)) then + ERROR STOP 'Array not allocated' + end if + allocate(temp(size(arr) + times)) + temp(1:size(arr)) = arr + temp(size(arr) + 1:size(temp)) = val + call move_alloc(temp, arr) + end subroutine append_to_integer_array_times +end module day_09_utils +program day_09 + use iso_fortran_env, only: int64 + use day_09_utils + implicit none + integer :: io, ios, i, j, block_n, ct, block_start, block_end, space_start, space_end + integer(kind=int64) :: res + character(len=1) :: c + integer, allocatable :: system(:), work(:) + logical :: is_space, space_block_start + + open(newunit=io, file='./day_09_input.txt', status='old', action='read', access='stream') + is_space = .false. + block_n = 0 + do + read(io, iostat=ios) c + if (ios /= 0) exit + read(c, *, iostat=ios) i + if(ios /= 0) exit + if (i == 0) then + is_space = .false. + cycle + end if + if (.not. allocated(system)) then + allocate(system(i)) + system(1:i) = block_n + is_space = .true. + block_n = block_n + 1 + else + if (is_space) then + call append_to_integer_array_times(system, -1, i) + is_space = .false. + else + call append_to_integer_array_times(system, block_n, i) + block_n = block_n + 1 + is_space = .true. + end if + end if + end do + allocate(work(size(system))) + work = system + ct = count(work > -1) + outer: do + do i = 1, size(work) + if (i == ct) exit outer ! we are done + if(work(i) < 0) then + call swap_to_first_positive_integer_from_end(work, i) + exit + end if + end do + end do outer + res = 0 + do i = 1, size(work) + if(work(i) > -1) then + res = res + ((i-1) * work(i)) + else + end if + end do + print *, res + ! start_part_2 + res = 0 + deallocate(work) + allocate(work(size(system))) + work = system + block_n = -1 + block_start = -1 + block_end = -1 + do i = 0, size(work) -1 + if(block_n == -1 .and. work(size(work) - i) > -1) then + ! we are starting a block + block_end = size(work) - i + block_n = work(size(work) - i) + else if (block_n /= -1 .and. block_n /= work(size(work)-i)) then + ! we are ending the block + block_start = size(work) - i + ! lets try to move the block + space_block_start = .true. + do j = 1, size(work) + if (j >= block_start) exit + if(space_block_start .and. work(j) == -1) then + space_start = j + space_block_start = .false. + else if (.not. space_block_start .and. work(j) /= -1) then + space_end = j + space_block_start = .true. + if(space_end - space_start >= block_end - block_start) then + work(space_start:(space_start + (block_end - (block_start +1) ))) = work((block_start +1):block_end) + work(block_start+1:block_end) = -1 + block_n = -1 + block_start = -1 + block_end = -1 + + exit + end if + end if + end do + block_n = work(size(work) - i) + block_end = size(work) - i + block_start = -1 + end if + end do + do i = 1, size(work) + if(work(i) > -1) then + res = res + ((i-1) * work(i)) + end if + end do + print *, res +end program day_09 + + |