aru/aoc-2021 - Change LEPYG5TCESV3A6ROIRNPP4J3ETGDKMURPT2W3LJRK7T3PV5UJHGAC

Day 06 in Common Lisp optimalization

There's no need to rotate the array itself when you can just rotate an offset into the array.

Created by aru on December 7, 2021

LEPYG5TCESV3A6ROIRNPP4J3ETGDKMURPT2W3LJRK7T3PV5UJHGAC

Dependencies

[2] BJFOTQAD5BJHNZ3NP7LUEMHIUKSHI7C7WF3KQN2ALT3NY2QJKLJAC

In channels

main

Change contents

Replacement in 06/solution.lisp at line 30 [2.68]

B:BD[2.828] → [2.828:1086]

    (dotimes (n days)
      (let ((zeroes (aref working 0)))
        (loop for x from 1 to 8
              do (setf (aref working (1- x)) (aref working x)))
        (setf (aref working 8) zeroes)
        (setf (aref working 6) (+ zeroes (aref working 6)))))

[2.828]

[2.1086]

    (dotimes (offset (1+ days))
      (setf (aref working (mod (+ offset 6) 9)) (+ (aref working (mod (+ offset 8) 9))
                                                   (aref working (mod (+ offset 6) 9)))))