Data commit

Task/Sierpinski-triangle/ACL2/sierpinski-triangle.acl2

@@ -0,0 +1,39 @@
+(defun pascal-row (prev)
+   (if (endp (rest prev))
+       (list 1)
+       (cons (+ (first prev) (second prev))
+             (pascal-row (rest prev)))))
+
+(defun pascal-triangle-r (rows prev)
+   (if (zp rows)
+       nil
+       (let ((curr (cons 1 (pascal-row prev))))
+          (cons curr (pascal-triangle-r (1- rows) curr)))))
+
+(defun pascal-triangle (rows)
+   (cons (list 1)
+         (pascal-triangle-r rows (list 1))))
+
+(defun print-odds-row (row)
+   (if (endp row)
+       (cw "~%")
+       (prog2$ (cw (if (oddp (first row)) "[]" "  "))
+               (print-odds-row (rest row)))))
+
+(defun print-spaces (n)
+   (if (zp n)
+       nil
+       (prog2$ (cw " ")
+               (print-spaces (1- n)))))
+
+(defun print-odds (triangle height)
+   (if (endp triangle)
+       nil
+       (progn$ (print-spaces height)
+               (print-odds-row (first triangle))
+               (print-odds (rest triangle) (1- height)))))
+
+(defun print-sierpenski (levels)
+   (let ((height (1- (expt 2 levels))))
+      (print-odds (pascal-triangle height)
+                  height)))