From 84bac718cf36291b7bc8004b8e3c0f60fc9ec39d Mon Sep 17 00:00:00 2001
From: nsfisis <nsfisis@gmail.com>
Date: Wed, 11 Sep 2024 03:28:16 +0900
Subject: 13-Mod-3 (incomplete)

---
 problems/13-Mod-3/a.rb | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 problems/13-Mod-3/a.rb

(limited to 'problems/13-Mod-3/a.rb')

diff --git a/problems/13-Mod-3/a.rb b/problems/13-Mod-3/a.rb
new file mode 100644
index 0000000..b0e909b
--- /dev/null
+++ b/problems/13-Mod-3/a.rb
@@ -0,0 +1,56 @@
+def f1(n)
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n == 3 ? 0 : n
+end
+
+def f2(n)
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      0
+  n == 3 ? 0 : n
+end
+
+def f3(n)
+  n = ((n >> 0) & 0b1111) +
+      ((n >> 4) & 0b1111) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      0
+  n == 3 ? 0 : n
+end
+
+256.times do |n|
+  expected = n % 3
+  actual = f3(n)
+
+  if actual != expected
+    puts "#{actual} != #{expected} (#{n}; #{"%08b" % n})"
+  end
+end
-- 
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