[FP/HW1] Finished second exercise, but it has bugs

1 files changed, 26 insertions, 4 deletions

diff --git a/Year 2/Functional Programming/hw1.rkt b/Year 2/Functional Programming/hw1.rkt
index 056df23..3f78abd 100644
--- a/Year 2/Functional Programming/hw1.rkt
+++ b/Year 2/Functional Programming/hw1.rkt
@@ -19,17 +19,39 @@
 ;;; Задача 2
 
 (define (swap-last2-digits n)
-  (+ (* (quotient n 100) 100) (* (remainder n 10) 10) (quotient (remainder n 100) 10)))
+  (+ (* (quotient n 100) 100)
+     (* (remainder n 10) 10)
+     (quotient (remainder n 100) 10)))
 
 (define (rotate-left n)
-  (if (< n 9)
+  (if (<= n 9)
     n
-    (swap-last2-digits (+ (* (rotate-left (quotient n 10)) 10) (remainder n 10)))))
+    (swap-last2-digits (+ (* (rotate-left (quotient n 10)) 10)
+                          (remainder n 10)))))
 
 (define (pow10 n)
   (if (= n 0)
     1
     (* 10 (pow10 (sub1 n)))))
 
+(define (numlen n)
+  (if (= n 0)
+    0
+    (add1 (numlen (quotient n 10)))))
+
 (define (rotate-left-preserved n d)
-  (rotate-left (remainder n (pow10 d))))
+  (define pbl (pow10 (- (numlen n) d)))
+  (+ (* (quotient n pbl) pbl)
+     (if (< (remainder n pbl) pbl)
+       (* (rotate-left (remainder n pbl)) 10)
+       (rotate-left (remainder n pbl)))))
+
+(define (max-rot n)
+  (define nrlen (sub1 (numlen n)))
+  (define (helper i current biggest)
+    (if (>= i nrlen)
+      biggest
+      (helper (add1 i)
+              (rotate-left-preserved current (add1 i))
+              (if (> current biggest) current biggest))))
+  (helper 0 (rotate-left n) 0))