View difference between Paste ID: z8LxJTq4 and tmJQ0p8j

 (defun flatten (x &optional y)
   (declare (optimize (speed 3) (safety 0)))
   (cond
     ((null x)
      (cond
        ((null y) nil)
        ((listp (car y))
         (flatten (car y) (cdr y)))
        (t (cons (car y) (flatten (cdr y))))))
     ((listp (car x))
      (flatten (car x) (if y (list (cdr x) y) (cdr x))))
     (t (cons (car x) (flatten (cdr x) y)))))
 
 (defun flatten-1 (l)
   (declare (optimize (speed 3) (safety 0)))
   (cond
     ((null l) nil)
     ((atom l) (list l))
     (t (loop for a in l appending (flatten-1 a)))))
 
 (defun flatten-2 (l)
   (declare (optimize (speed 3) (safety 0)))
   (when l
     (if (atom l)
 	(list l)
 	(mapcan #'flatten-2 l))))
 
 (defun flatten-3 (x)
   (declare (optimize (speed 3) (safety 0)))
   (do ((a x))
       ((null a))
-    (if (listp (car a))
+    (if (consp (car a))
-	(do ((b (car a) (cdr b))
+        (do ((b (car a) (cdr b))
-	     (c a)
+             (c a)
-	     (d (cdr a)))
+             (d (cdr a)))
-	    ((null b)
+            ((null b)
-	     (and (setf (cdr c) d) nil))
+             (and (setf (cdr c) d) nil))
-	  (setf (car c) (car b)
+          (setf (car c) (car b)
-		(cdr c) (cdr b)
+                (cdr c) (cdr b)
-		c (or (cdr c) c)))
+                c (or (cdr c) c)))
-	(setf a (cdr a)))) x)
+        (setf a (cdr a)))) x)
-
+
-;; 353
+(defun flatten-4 (l)
-;; 2056
+
-;; 1230
+
-;; 63
+
     ((atom l) (list l))
-(let ((test (get-internal-real-time)))
+    (t (loop for a in l nconcing (flatten-4 a)))))
-  (dotimes (i 1e6)
+
-    (flatten '(1 2 (3 4) (5 (6 (7 8) 9 a (10))) b (10.5 (1.6) (1.7)) 11)))
+(defun flatten-5 (x &aux (res (list nil)))
-  (print (- (get-internal-real-time) test))
+
-  (setf test (get-internal-real-time))
+  (do ((x x) (y nil) (r res))
-  (dotimes (i 1e6)
+      (nil)
-    (flatten-2 '(1 2 (3 4) (5 (6 (7 8) 9 a (10))) b (10.5 (1.6) (1.7)) 11)))
+    (cond
-  (print (- (get-internal-real-time) test))
+      ((null x)
-  (setf test (get-internal-real-time))
+       (cond
-  (dotimes (i 1e6)
+         ((null y) (return-from flatten-5 (cdr res)))
-    (flatten-1 '(1 2 (3 4) (5 (6 (7 8) 9 a (10))) b (10.5 (1.6) (1.7)) 11)))
+         ((listp (car y))
-  (print (- (get-internal-real-time) test))
+          (setq x (car y) y (cdr y)))
-  (setf test (get-internal-real-time))
+         (t (rplacd r (list (car y)))
-  (dotimes (i 1e6)
+            (setq r (cdr r)
-    (flatten-3 '(1 2 (3 4) (5 (6 (7 8) 9 a (10))) b (10.5 (1.6) (1.7)) 11)))
+                  x (cdr y)
-  (print (- (get-internal-real-time) test)))
+                  y nil))))
       ((listp (car x))
        (setq y (if y (list (cdr x) y) (cdr x))
              x (car x)))
       (t (rplacd r (list (car x)))
          (setq r (cdr r)
                x (cdr x))))))
 
 (defun test-flatten (data)
   (declare (optimize (speed 3) (safety 0)))
   (let ((test (get-internal-real-time)))
     (dotimes (i 1e6) (flatten data))
     (print (- (get-internal-real-time) test))
     (setf test (get-internal-real-time))
     (dotimes (i 1e6) (flatten-1 data))
     (print (- (get-internal-real-time) test))
     (setf test (get-internal-real-time))
     (dotimes (i 1e6) (flatten-2 data))
     (print (- (get-internal-real-time) test))
     (setf test (get-internal-real-time))
     (dotimes (i 1e6)
       (flatten-3 (copy-tree data)))
     (print (- (get-internal-real-time) test))
     (setf test (get-internal-real-time))
     (dotimes (i 1e6) (flatten-4 data))
     (print (- (get-internal-real-time) test))
     (setf test (get-internal-real-time))
     (dotimes (i 1e6) (flatten-5 data))
     (print (- (get-internal-real-time) test))
     (print "--------------------- finished")))
 
 (let* ((data '(1 2 (3 4) (5 (6 (7 8) 9 a (10))) b (10.5 (1.6) (1.7)) 11))
        (data-1 (do ((i 10 (1- i)) (x))
 		   ((zerop i) (return x))
 		 (setf x (append x data))))
        (data-2 (do ((i 10 (1- i)) (x))
 		   ((zerop i) (return x))
 		 (setf x (append x data-1)))))
   (format t "data: ~s~&data-1: ~s~& data-2: ~s~&"
 	  data data-1 data-2)
   (test-flatten data)
   (test-flatten data-1)
   (test-flatten data-2))
 
 ;; 890
 ;; 2806
 ;; 4735
 ;; 686
 ;; 811
 ;; 414
 ;; --------------------- finished
 ;; 3729
 ;; 12915
 ;; 21658
 ;; 6584
 ;; 7269
 ;; 3391
 ;; --------------------- finished
 ;; 50071
 ;; 133508
 ;; 215169
 ;; 73918
 ;; 70899
 ;; 33164
 ;; --------------------- finished