From b69c6dab84dbceb45cdb28c6f09370ec6bbf1498 Mon Sep 17 00:00:00 2001
From: Mark <53903062+andemark@users.noreply.github.com>
Date: Fri, 7 Apr 2023 04:40:45 +0000
Subject: ch-2.raku do-over

---
 challenge-211/mark-anderson/raku/ch-2.raku | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

(limited to 'challenge-211')

diff --git a/challenge-211/mark-anderson/raku/ch-2.raku b/challenge-211/mark-anderson/raku/ch-2.raku
index 255ada41f4..8af4568b57 100644
--- a/challenge-211/mark-anderson/raku/ch-2.raku
+++ b/challenge-211/mark-anderson/raku/ch-2.raku
@@ -1,6 +1,11 @@
 #!/usr/bin/env raku
 use Test;
 
+# This is a do-over after reading other's solutions.
+# Jorg Sommrey and W. Luis Mochan explained that if one subset's average
+# equals the average of the whole list then the other subset will have
+# the same average. 
+
 ok  split-same-avg(1,2,3,4,5,6,7,8); # [1 8] [2 3 4 5 6 7]
 nok split-same-avg(1,3);
 ok  split-same-avg(3,3,5,5,5,2,2,1); # [2 3 3 5] [1 2 5 5]
@@ -8,14 +13,11 @@ nok split-same-avg(5,5,5,2,2,1);
 
 sub split-same-avg(*@nums)
 {
-    for (^@nums).combinations(1..@nums.elems div 2) -> @a is copy
-    {
-        my @b = (^@nums (-) @a).keys;
+    my $avg = @nums.sum / @nums.elems;
 
-        @a = @nums[@a];
-        @b = @nums[@b];
-
-        return True if @a.sum / @a.elems == @b.sum / @b.elems
+    for (^@nums).combinations(1..@nums.elems div 2) -> @a
+    {
+        return True if @nums[@a].sum / @nums[@a].elems == $avg
     }
 
     return False
-- 
cgit