SOLVED: Help with an algorithm...

[Paul Dupuis]

On 8/5/2019 11:53 AM, Paul Dupuis via use-livecode wrote:
> Today is not my coding day. I have a problem I should be able to 
> design a solution for an am struggling. Clearly I am missing "something"
>
> I have 2 lists (LISTNEW and LISTOLD) of the following format:
>
> ParentA
> <space>Child 1
> <space>Child 2
> <space>etc.
> ParentB
> <space>Child 1
> <space>etc.
> etc.
>
> The parents are in alphabetical sorted order, the children may not be 
> in sorted order
>
> I need to hunt through LISTOLD comparing the LISTOLD Parents to the 
> LISTNEW Parents
>   FOR any LISTOLD Parent present in LISTNEW, check the Children of the 
> matching Parents and add any Child for the LISTOLD Parent that is not 
> already under its matching LISTNEW Parent
>   FOR any LISTOLD Parent NOT in LISTNEW, I can ignore the Parent and 
> its Children
>
> I can not seem to write an approach to solve this today. Does any body 
> have some code so solve this they may be willing to share?
>

Thank you everyone who responded. Apparently, I really just needed a 
nudge, which Craig's first response provided. All replies helped though. 
Routine is now coded, tested, and working correctly.