Initial data commit

Task/Sorting-algorithms-Insertion-sort/Common-Lisp/sorting-algorithms-insertion-sort-1.lisp

@@ -0,0 +1,13 @@
+(defun span (predicate list)
+  (let ((tail (member-if-not predicate list)))
+    (values (ldiff list tail) tail)))
+
+(defun less-than (x)
+  (lambda (y) (< y x)))
+
+(defun insert (list elt)
+  (multiple-value-bind (left right) (span (less-than elt) list)
+    (append left (list elt) right)))
+
+(defun insertion-sort (list)
+  (reduce #'insert list :initial-value nil))

Task/Sorting-algorithms-Insertion-sort/Common-Lisp/sorting-algorithms-insertion-sort-2.lisp

@@ -0,0 +1,18 @@
+(defun insertion-sort (sequence &optional (predicate #'<))
+  (if (cdr sequence)
+      (insert (car sequence)                 ;; insert the current item into
+              (insertion-sort (cdr sequence) ;; the already-sorted
+                              predicate)     ;; remainder of the list
+              predicate)
+      sequence)) ; a list of one element is already sorted
+
+(defun insert (item sequence predicate)
+  (cond ((null sequence) (list item))
+        ((funcall (complement predicate)      ;; if the first element of the list
+                              (car sequence)  ;; isn't better than the item,
+                              item)           ;; cons the item onto
+         (cons item sequence))                ;; the front of the list
+        (t (cons (car sequence) ;; otherwise cons the first element onto the front of
+                 (insert item   ;; the list of the item sorted with the rest of the list
+                         (cdr sequence)
+                         predicate)))))