Hi Ladislav, 15-Jul-2000 you wrote:
>Hi,
>don't know, what is the problem, but here is a merge-sort working
>for me looong time:
[...]
Thanks! In the meantime, I got it working by simply having the temporary
variables as parameters to the function. Mean, but it works.
As a curiosity, I also got the version of merge-sort working which uses less
memory. I'll attach it here, just in case anybody finds it interesting. It's
less artistic, but I guess that's just the price you have to pay for using
less memory.
Kind regards,
--
Ole Friis <[EMAIL PROTECTED]>
Amiga is a trademark of Amiga Inc.
; Merge sorting, uses only memory proportional to the length of list,
; instead of memory proportional to (length of list)*log(length of list)
sort-list: function [list cfunc] [sort-list2 low2] [
sort-list2: func [list list2 cfunc low high middle] [
if (high - low) > 1 [
; Sort recursively
middle: to-integer (low + high) / 2
sort-list2 list2 list :cfunc low middle 0
sort-list2 list2 list :cfunc middle high 0
; Merge list2[low..middle) and list2[middle..high) into list[low..high]
list: skip list (low - 1)
low2: middle
while [(low < middle) and (low2 < high)] [
either cfunc (pick list2 low) (pick list2 low2) [
change list pick list2 low
low: low + 1
] [
change list pick list2 low2
low2: low2 + 1
]
list: next list
]
; Append the missing items
for low low (middle - 1) 1 [
change list pick list2 low
list: next list
]
for low2 low2 (high - 1) 1 [
change list pick list2 low2
list: next list
]
]
]
sort-list2 list (copy list) :cfunc 1 (length? list) + 1 0
]
