challenge 151 raku solutions

2 files changed, 23 insertions, 1 deletions

diff --git a/challenge-147/feng-chang/raku/ch-1.raku b/challenge-147/feng-chang/raku/ch-1.raku
index d3dab98fae..41da33cad4 100755
--- a/challenge-147/feng-chang/raku/ch-1.raku
+++ b/challenge-147/feng-chang/raku/ch-1.raku
@@ -5,7 +5,7 @@ unit sub MAIN(UInt:D \num = 20);
 my @lefty-primes = 2, 3, 5, 7;
 my ($start, $end) = 0, 3;
 
-my UInt $sz  = @lefty-primes.elems;
+my UInt $sz = @lefty-primes.elems;
 
 while $sz < num {
     for 1..9 -> \d {
diff --git a/challenge-147/feng-chang/raku/ch-2a.raku b/challenge-147/feng-chang/raku/ch-2a.raku
new file mode 100755
index 0000000000..bf937bd660
--- /dev/null
+++ b/challenge-147/feng-chang/raku/ch-2a.raku
@@ -0,0 +1,22 @@
+#!/bin/env raku
+
+# reference https://gfldex.wordpress.com/2022/01/15/manual-hypering/
+
+sub needle(int \b) {
+    sub is-pentagon(\n is raw) { (1 + sqrt(1 + 24 * n)) %% 6 }
+    sub P(\n is raw) { n * (3 * n - 1) div 2 }
+
+    loop (my int $s = 1; $s < b; ++$s) {
+        my \bp = P(b);
+        my \sp = P($s);
+        if is-pentagon(bp + sp) && is-pentagon(bp - sp) {
+            return |(b, $s);
+        }
+    }
+}
+
+sub infix:<notnilor>(\maybenil, \alternative) {
+    maybenil =:= Nil ?? alternative !! maybenil
+}
+
+say (^∞).hyper(:batch(8), :degree(16)).map({ $_ with .&needle }).head;