From: Ben Harris <bjh21@bjh21.me.uk>
Date: Fri, 31 May 2024 08:13:15 +0000 (+0100)
Subject: 20b done
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~bjharris/git?a=commitdiff_plain;h=2902a81d6c0152fec9f739280478bd480a1ed618;p=aoc-2022.git

20b done

The problem was that my input included repeated numbers, so I needed to
keep track of which instance of a repeated number I was moving.  I
achieved this by applying the mixing operation to a list of indices into
the original array, looking up shift amounts in the original array and
translating back to the original values at the end.
---

diff --git a/20/20a.bqn b/20/20a.bqn
index e1f13e7..bd045bf 100644
--- a/20/20a.bqn
+++ b/20/20a.bqn
@@ -1,8 +1,9 @@
 Prep←•ParseFloat¨
 
 Main←{ 𝕊 orig:
-  Twiddle←{ (1⊸⌽)⌾((1+(¯1+≠𝕩)|𝕨)⊸↑) (𝕩⊐𝕨)⌽𝕩 }
-  cur ← orig Twiddle´ ⌽orig
+  Twiddle←{ (1⊸⌽)⌾((1+(¯1+≠𝕩)|(𝕨⊑orig))⊸↑) (𝕩⊐𝕨)⌽𝕩 }
+  perm ← (↕≠orig) Twiddle´ ⌽↕≠orig
+  cur ← perm⊏orig
   +´((≠cur)|(cur⊐0)+⟨1000,2000,3000⟩)⊏cur
 }
 
diff --git a/20/20b.bqn b/20/20b.bqn
index bdf00f4..29a126d 100644
--- a/20/20b.bqn
+++ b/20/20b.bqn
@@ -1,10 +1,11 @@
 Prep←•ParseFloat¨
 
 Main←{ 𝕊 orig:
-  Twiddle←{ (1⊸⌽)⌾((1+(¯1+≠𝕩)|𝕨)⊸↑) (𝕩⊐𝕨)⌽𝕩 }
+  Twiddle←{ (1⊸⌽)⌾((1+(¯1+≠𝕩)|(𝕨⊑orig))⊸↑) (𝕩⊐𝕨)⌽𝕩 }
   Mix←Twiddle´⟜⌽
   orig ×↩ 811589153
-  cur ← orig Mix˜⍟10 orig
+  perm ← (↕≠orig) Mix˜⍟10 ↕≠orig
+  cur ← perm⊏orig
   +´((≠cur)|(cur⊐0)+⟨1000,2000,3000⟩)⊏cur
 }