From 6ae44d09faa0ae353c0818705503cad42127d102 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sun, 3 Mar 2024 15:03:41 +0100
Subject: Even more samples

wtf
---
 samples/rosetta/hamming_numbers.bruijn | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 samples/rosetta/hamming_numbers.bruijn

(limited to 'samples/rosetta/hamming_numbers.bruijn')

diff --git a/samples/rosetta/hamming_numbers.bruijn b/samples/rosetta/hamming_numbers.bruijn
new file mode 100644
index 0000000..426223d
--- /dev/null
+++ b/samples/rosetta/hamming_numbers.bruijn
@@ -0,0 +1,28 @@
+:import std/Combinator .
+:import std/Number .
+:import std/List .
+
+merge y [[[∅?1 0 (1 [[2 [[go]]]])]]]
+	go 3 <? 1 (3 : (6 2 4)) (1 : (6 5 0))
+
+# classic version while avoiding duplicate generation
+hammings-classic (+1) : (foldr u empty ((+2) : ((+3) : {}(+5))))
+	u [[y [merge 1 ((mul 2) <$> ((+1) : 0))]]]
+
+:test ((hammings-classic !! (+42)) =? (+162)) ([[1]])
+
+# enumeration by a chain of folded merges (faster)
+hammings-folded ([(0 ∘ a) ∘ (0 ∘ b)] (foldr merge1 empty)) $ c
+	merge1 [[1 [[1 : (merge 0 2)]]]]
+	a iterate (map (mul (+5)))
+	b iterate (map (mul (+3)))
+	c iterate (mul (+2)) (+1)
+
+:test ((hammings-folded !! (+42)) =? (+162)) ([[1]])
+
+# --- output ---
+
+main [first-twenty : (n1691 : {}n1000000)]
+	first-twenty take (+20) hammings-folded
+	n1691 hammings-folded !! (+1690)
+	n1000000 hammings-folded !! (+999999)
-- 
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