Writing A Function Using Helper Functions

Question

I\'m trying to write a function in Scheme that takes two strings as input and returns a list of all optimal pairs of strings. In order to do this, I know that I need to make use

Answer 1

I think you have almost everything you need except for a function that can sort a list using a predicate function.

If your Scheme interpreter does not provide a sorting function, you can use one found at Wikibooks . You'll have to adapt it to take a predicate function instead of using <= as the default predicate function.

Your predicate function can be:

(define (compare-by-alignment lhs rhs)
   (<= (alignment-score-tail lhs) (alignment-score-tail rhs)))

You can call merge-sort using your list and predicate function as:

(merge-sort lst compare-by-alignment)