Data update

Task/Sorting-algorithms-Pancake-sort/Raku/sorting-algorithms-pancake-sort-1.raku

@@ -1,10 +1,10 @@
-sub pancake_sort ( @a is copy ) {
+sub pancake_sort(@a is copy) {
     my $endpoint = @a.end;
     while $endpoint > 0 and not [<] @a {
         my $max_i = [0..$endpoint].max: { @a[$_] };
         my $max   = @a[$max_i];
         if @a[$endpoint] == $max {
-            $endpoint-- while @a[$endpoint] == $max;
+            $endpoint-- while $endpoint >= 0 and @a[$endpoint] == $max;
             next;
         }
         # @a[$endpoint] is not $max, so it needs flipping;
@@ -15,6 +15,10 @@ sub pancake_sort ( @a is copy ) {
     }
     return @a;
 }
-my @data = 6, 7, 2, 1, 8, 9, 5, 3, 4;
-say 'input  = ' ~ @data;
-say 'output = ' ~ @data.&pancake_sort;
+
+for <6 7 2 1 8 9 5 3 4>,
+    <4 5 7 1 46 78 2 2 1 9 10>,
+    <0 -9 -8 2 -7 8 6 -2 -8 3> -> @data {
+   say 'input  = ' ~ @data;
+   say 'output = ' ~ @data.&pancake_sort
+}

Task/Sorting-algorithms-Pancake-sort/Raku/sorting-algorithms-pancake-sort-2.raku

@@ -0,0 +1,23 @@
+# 20240908 Updated Raku programming solution
+
+sub pancake-sort(@data is copy) { # imperative
+   for @data.elems - 1 ... 1 {
+      @data[0 .. @data[0..$_].maxpairs[*-1].key] .= reverse;
+      @data[0 .. $_] .= reverse;
+   }
+   return @data
+}
+
+sub pancake_sort(@data is copy) { # recursive
+   return @data if @data.elems <= 1;
+   @data[0 .. @data.maxpairs[*-1].key] .= reverse;
+   return pancake_sort(@data[1..*-1]).append: @data[0]
+}
+
+for <6 7 2 1 8 9 5 3 4>,
+    <4 5 7 1 46 78 2 2 1 9 10>,
+    <0 -9 -8 2 -7 8 6 -2 -8 3> -> @data {
+   say 'input  = ' ~ @data;
+   say 'output = ' ~ pancake-sort(@data);
+   say 'output = ' ~ pancake_sort(@data) ~ "\n"
+}