From 3a026e10f65e58ef4385d27f22c2b0a797737b5b Mon Sep 17 00:00:00 2001
From: frasiyav <notarealemail@notarealemailprovider.com>
Date: Sat, 24 Oct 2020 10:10:20 -0600
Subject: Added N Queens and Knight's Tour

---
 examples/fifty.bqn | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(limited to 'examples')

diff --git a/examples/fifty.bqn b/examples/fifty.bqn
index 2a9cf317..c3c76a76 100644
--- a/examples/fifty.bqn
+++ b/examples/fifty.bqn
@@ -146,6 +146,31 @@ IndexFromCombination‿CombinationFromIndex ← {
 SymmetricArray ← ⍉⊸≡ ∧ 1⊸⍉⊸≡
 ! SymmetricArray +⌜´ 3⥊<2‿3‿7‿11
 
+# 25
+NQueens ← {
+  Arr ← {>(⊑⊸⊏⟜𝕩∾1⊸⊑)¨/¬(↕𝕨)∊⎉1𝕩⥊∘+⎉1‿2(-⟜↕¯1⊑≢𝕩)×⌜¯1‿0‿1}
+  𝕩 Arr⍟(𝕩-1) ≍˘↕𝕩
+}
+QueenCheck ← {
+  ! 1=≠≢𝕩
+  ! (↕≠𝕩)≡∧𝕩
+  ! ((2⥊≠𝕩)⥊1)≡(=⌜˜↕≠𝕩)≥(|-⌜˜𝕩)=|-⌜˜↕≠𝕩  
+}
+QueenCheck˘ NQueens 8
+
+#26
+KnightsTour ← {
+  Kmoves ← {
+    t ← (⥊↕𝕩‿𝕩)+⌜<˘8‿2⥊2‿1‿2‿¯1‿1‿2‿1‿¯2‿¯1‿2‿¯1‿¯2‿¯2‿1‿¯2‿¯1
+    (∧´⎉1(>t)∊↕𝕩) /¨○<˘ 𝕩{+⟜(𝕨⊸×)´⌽𝕩}¨t
+  }
+  m ← >↑˜¨⟜(⌈´≠¨) Kmoves 𝕩
+  b ← (𝕩×𝕩)⥊1
+  F ← {b↩0⌾((¯1⊑𝕩)⊸⊑)b ⋄ 𝕩∾(⊑⍋+´˘(j⊏m)⊏b)⊑j←⊏⟜b⊸/(¯1⊑𝕩)⊏m}
+  𝕩‿𝕩⥊⍋F⍟(¯1+𝕩⋆2) 1⥊0
+}
+! (KnightsTour 6) ≡ 6‿6⥊0‿9‿20‿35‿6‿11‿21‿32‿7‿10‿19‿26‿8‿1‿34‿25‿12‿5‿33‿22‿31‿16‿27‿18‿2‿15‿24‿29‿4‿13‿23‿30‿3‿14‿17‿28
+
 # 34
 _pow ← {𝔽´𝔽˜⍟(/2|⌊∘÷⟜2⍟(↕·⌈2⋆⁼⊢)𝕩)𝕨}
 ! 847288609443 ≡ 3 ×_pow 25
-- 
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