[FP/HW2] Exercise 2 solution is very rough and half-working

1 files changed, 24 insertions, 17 deletions

diff --git a/Year 2/Functional Programming/hw2.rkt b/Year 2/Functional Programming/hw2.rkt
index a2db476..c0f4223 100644
--- a/Year 2/Functional Programming/hw2.rkt
+++ b/Year 2/Functional Programming/hw2.rkt
@@ -28,25 +28,32 @@
         [else (range-covers? range (cdr ranges))]))
 
 (define (woodcutters xs)
+  (define (calc-check xs fallen count)
+    (if (null? xs)
+      count
+      (calc xs fallen count)))
   (define (calc xs fallen count)
+    
     (define leftRange (cons (- (car (car xs)) (cdr (car xs))) (car (car xs))))
     (define rightRange (cons (cdr (car xs)) (+ (car (car xs)) (cdr (car xs)))))
-    (define currentRange (cond [(not (range-covers? leftRange fallen)) leftRange]
-                               [(not (range-covers? rightRange fallen)) rightRange]
-                               [else '()]))
-    (if (= (length xs) 0)
-      count
-      (max (calc (cdr xs)
-                 (list* currentRange fallen)
-                 (if (null? currentRange) count (add1 count))))))
-  (calc xs '() 0))
+
+    (define withLeft (if (range-covers? leftRange fallen)
+                         0
+                         (calc-check (cdr xs) (list* leftRange fallen) (add1 count))))
+    (define withRight (if (range-covers? rightRange fallen)
+                          0
+                          (calc-check (cdr xs) (list* rightRange fallen) (add1 count))))
+    (define noRange (calc-check (cdr xs) fallen count))
+
+    (max withLeft withRight noRange))
+  (calc-check xs '() 0))
 
 (woodcutters '((1 . 2) (2 . 1) (5 . 10) (10 . 9) (19 . 1))) ; → 3
-;(woodcutters '((1 . 2) (2 . 1) (5 . 10) (10 . 9) (20 . 1))) ; → 4
-;(woodcutters '((10 . 4) (15 . 1) (19 . 3) (20 . 1))) ; → 4
-;(woodcutters '((1 . 7) (3 . 11) (6 . 12) (7 . 6) (8 . 5) (9 . 11)
-;(15 . 3) (16 . 10) (22 . 2) (23 . 3) (25 . 7) (27 . 3) (34 . 5)
-;(35 . 10) (37 . 3) (39 . 4) (40 . 5) (41 . 1) (44 . 1) (47 . 7)
-;(48 . 11) (50 . 6) (52 . 5) (57 . 2) (58 . 7) (60 . 4) (62 . 1)
-;(67 . 3) (68 . 12) (69 . 8) (70 . 1) (71 . 5) (72 . 5)
-;(73 . 6) (74 . 4) ) ) ; → 10
+(woodcutters '((1 . 2) (2 . 1) (5 . 10) (10 . 9) (20 . 1))) ; → 4
+(woodcutters '((10 . 4) (15 . 1) (19 . 3) (20 . 1))) ; → 4
+; (woodcutters '((1 . 7) (3 . 11) (6 . 12) (7 . 6) (8 . 5) (9 . 11)
+; (15 . 3) (16 . 10) (22 . 2) (23 . 3) (25 . 7) (27 . 3) (34 . 5)
+; (35 . 10) (37 . 3) (39 . 4) (40 . 5) (41 . 1) (44 . 1) (47 . 7)
+; (48 . 11) (50 . 6) (52 . 5) (57 . 2) (58 . 7) (60 . 4) (62 . 1)
+; (67 . 3) (68 . 12) (69 . 8) (70 . 1) (71 . 5) (72 . 5)
+; (73 . 6) (74 . 4) ) ) ; → 10