initial ch-2.raku

1 files changed, 21 insertions, 0 deletions

diff --git a/challenge-100/mark-anderson/raku/ch-2.raku b/challenge-100/mark-anderson/raku/ch-2.raku
new file mode 100644
index 0000000000..b1464b8466
--- /dev/null
+++ b/challenge-100/mark-anderson/raku/ch-2.raku
@@ -0,0 +1,21 @@
+#!/usr/bin/env raku
+
+use Test;
+plan 4;
+
+is min-triangle-sum([[1], [2,4], [6,4,9], [5,1,7,2]]),  8;
+is min-triangle-sum([[3], [3,1], [5,2,3], [4,3,1,3]]),  7;
+is min-triangle-sum([[2], [3,4], [6,5,7], [4,1,8,3]]), 11;  
+is min-triangle-sum([[7], [3,6], [6,4,9], [5,1,7,2]]), 15;
+
+sub min-triangle-sum(@triangle) 
+{
+    my @a = (flat roundrobin @triangle[1]<>, @triangle[0]<>).rotor(2 => -1);
+    my $head = @a.shift.sum;
+    my $tail = @a.pop.sum;
+    my @mid = map -> $a, $b { $a.sum min $b.sum }, @a;
+    shift @triangle; 
+    @triangle[0] = [$head, |@mid, $tail];
+    min-triangle-sum(@triangle) if @triangle > 1;
+    @triangle[0].min;
+}