Merge pull request #9207 from andemark/challenge-246

ch-2.raku touch-up

1 files changed, 6 insertions, 20 deletions

diff --git a/challenge-246/mark-anderson/raku/ch-2.raku b/challenge-246/mark-anderson/raku/ch-2.raku
index b411ffd00a..52ef177f92 100644
--- a/challenge-246/mark-anderson/raku/ch-2.raku
+++ b/challenge-246/mark-anderson/raku/ch-2.raku
@@ -7,27 +7,13 @@ ok  linear-recurrence-of-second-order([4,1,2,-3,8]);
 
 sub linear-recurrence-of-second-order(@a)
 {
-    my @eqn = @a.rotor(3 => -2).head(2);
-    my $p = p(@eqn).narrow;
-    my $q = q(@eqn.pop, $p).narrow;
+    my @eqn = @a.rotor(3 => -2);
 
-    return False unless all($p, $q) ~~ Int;
+    my $p = (.[2] / .[0] given .[0] >>*>> .[1;1] >>-<< .[1] >>*>> .[0;1]).narrow given @eqn;
 
-    @a eqv (@a[0], @a[1], -> $a, $b { $a*$p + $b*$q }...*).head(5).Array 
-}
-  
-sub p(@a)
-{
-    given @a 
-    {
-        .[2] / .[0] given .[0] >>*>> .[1;1] >>-<< .[1] >>*>> .[0;1]
-    }
-}
+    my $q = ((.[2] - .[0]*$p) / .[1]).narrow given @eqn.tail;
 
-sub q(@a, $p)
-{
-    given @a
-    {
-        (.[2] - .[0]*$p) / .[1]
-    }
+    return False unless all($p, $q) ~~ Int;
+
+    @a eqv (@a[0], @a[1], { $^a*$p + $^b*$q }...*).head(5).Array 
 }