Data commit

Task/Hofstadter-Figure-Figure-sequences/Racket/hofstadter-figure-figure-sequences-1.rkt

@@ -0,0 +1,14 @@
+#lang racket/base
+
+(define r-cache (make-hash '((1 . 1) (2 . 3) (3 . 7))))
+(define s-cache (make-hash '((1 . 2) (2 . 4) (3 . 5) (4 . 6))))
+
+(define (extend-r-s!)
+  (define r-count (hash-count r-cache))
+  (define s-count (hash-count s-cache))
+  (define last-r (ffr r-count))
+  (define new-r (+ (ffr r-count) (ffs r-count)))
+  (hash-set! r-cache (add1 r-count) new-r)
+  (define offset (- s-count last-r))
+  (for ([val (in-range (add1 last-r) new-r)])
+    (hash-set! s-cache (+ val offset) val)))

Task/Hofstadter-Figure-Figure-sequences/Racket/hofstadter-figure-figure-sequences-2.rkt

@@ -0,0 +1,5 @@
+(define (ffr n)
+  (hash-ref r-cache n (lambda () (extend-r-s!) (ffr n))))
+
+(define (ffs n)
+  (hash-ref s-cache n (lambda () (extend-r-s!) (ffs n))))

Task/Hofstadter-Figure-Figure-sequences/Racket/hofstadter-figure-figure-sequences-3.rkt

@@ -0,0 +1,13 @@
+(displayln (map ffr (list 1 2 3 4 5 6 7 8 9 10)))
+(displayln (map ffs (list 1 2 3 4 5 6 7 8 9 10)))
+
+(displayln "Checking for first 1000 integers:")
+(displayln (if (equal? (sort (append (for/list ([i (in-range 1 41)])
+                                       (ffr i))
+                                     (for/list ([i (in-range 1 961)])
+                                       (ffs i)))
+                             <)
+                       (for/list ([i (in-range 1 1001)])
+                         i))
+               "Test passed"
+               "Test failed"))