day 9: fix bug that didn't change the answer

9.rkt

@@ -21,7 +21,7 @@
 ;; continuously sort the part of the vector below the iterator, and call contains-sum?
 (define (part1 vec)
   (for*/first ([i (in-range 25 (vector-length vec))] [x (in-value (vector-ref vec i))]
-               #:unless (contains-sum? vec 0 i x))
+               #:unless (contains-sum? (vector-copy vec (- i 25) i) 0 25 x))
     (cons i x)))
 
 (define (part2 vec pt1-ans)