day07: make a bit more idiomatic (i think)

day07.scm

@@ -7,31 +7,25 @@
 (define numbers (map string->number (string-split (read-line) ",")))
 
 ; PART 1
-(define sorted (sort numbers <))
+(let* ((sorted (sort numbers <))
-(define median (list-ref sorted (floor/ (length numbers) 2)))
+       (median (list-ref sorted (floor/ (length numbers) 2)))
-
+       (part1
-(define (part1)
+        (foldl (lambda (x y) (+ x (abs (- y median))))
-  (foldl
+               0
-   (lambda (x y) (+ x (abs (- y median))))
+               numbers)))
-   0
+  (format #t "part 1: ~A~%" part1))
-   numbers))
-
 
 ; PART 2
 (define (triangular n) (/ (* n (+ n 1)) 2))
 
 (define (part2- avg)
-  (foldl
+  (foldl (lambda (x y) (+ x (triangular (abs (- y avg)))))
-   (lambda (x y) (+ x (triangular (abs (- y avg)))))
+         0
-   0
+         numbers))
-   numbers))
 
-(define avgCeil (ceiling/ (foldl + 0 numbers) (length numbers)))
+(let* ((len (length numbers))
-(define avgFloor (floor/ (foldl + 0 numbers) (length numbers)))
+       (sum (foldl + 0 numbers))
-
+       (avg-ceil (ceiling/ sum len))
-(define (part2)
+       (avg-floor (floor/ sum len))
-  (min (part2- avgCeil) (part2- avgFloor)))
+       (part2 (min (part2- avg-ceil) (part2- avg-floor))))
-
+  (format #t "part 2: ~A~%" part2))
-
-(format #t "part 1: ~A~%" (part1))
-(format #t "part 2: ~A~%" (part2))