Fix the recursive optimized power calculation

[TD_LISP.git] / exercices / lists.lsp

diff --git a/exercices/lists.lsp b/exercices/lists.lsp
index e97d74796833b3869973bd155c33bb1b69a650d4..35590dada335ff070e4a9546859cdafbe8777b1c 100755 (executable)
--- a/exercices/lists.lsp
+++ b/exercices/lists.lsp
@@ -118,11 +118,11 @@
 
 (define (aplatir L) 
   (cond
-    ((null? L) nil)
-    ((atom? L) (list L)) ;FIXME: the "casting" is not working properly
+    ((null? L) '())
+    ((atom? L) (list L))
     ((append (aplatir (first L)) (aplatir (rest L))))))
 (println "aplatir/flat")
-;(println (aplatir T))
+(println (aplatir T))
 (println (flat T))
 
 ;(trace nil)
@@ -169,7 +169,7 @@
     ((append 
        ;the pivot is the first element of the list
        (qsort (list< (first L) (rest L))) 
-       (cons (first L) '()) 
+       (list (first L))
        (qsort (list>= (first L) (rest L)))))))
 (println "qsort")
 (println (qsort C))
@@ -202,5 +202,24 @@
     ((and (inclu L1 L2) (inclu L2 L1) true))))
 (println "filtre")
 (println (filtre L1 L2 ?))
+(println (filtre L M ?))
+
+;algorithm written on the board
+(define (filtrerec L1 L2 C)
+  ;FIXME: use the function argument C
+  (cond
+    ((null? L1)
+      (cond
+        ((null? L2) true)
+        ((= '? (first L2)) (filtrerec L1 (rest L2)))
+        (nil)))
+    ((null? L2) (filtrerec L2 L1))
+    ((= '? (first L1)) (filtrerec (rest L1) L2))
+    ((= '? (first L2)) (filtrerec L1 (rest L2)))
+    ((= (first L1) (first L2)) (filtrerec (rest L1) (rest L2)) )
+    (nil)))
+(println "filtrerec")
+(println (filtrerec L1 L2 ?))
+(println (filtrerec L M ?))
 
 (exit)