--- /dev/null
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my @l = split /[,\s]/, <>;
+
+my $pos = 0;
+my $skip = 0;
+# my @nodes = (0 .. 4);
+my @nodes = (0 .. 255);
+my $n = @nodes;
+
+for my $i (@l) {
+ my $end = $pos + $i;
+ my @to_rev;
+ say "pos=$pos skip $skip i=$i ", join(',', @nodes);
+ if ($end > $n) {
+ push @to_rev, splice @nodes, $pos;
+ push @to_rev, splice @nodes, 0, $end - $n;
+ @to_rev = reverse @to_rev;
+ say "to_rev = ", join(',', @to_rev);
+ unshift @nodes, splice @to_rev, @to_rev-($end-$n);
+ push @nodes, @to_rev;
+ } else {
+ push @to_rev, splice @nodes, $pos, $i;
+ splice @nodes, $pos, 0, reverse @to_rev;
+ }
+ $pos += $i + $skip++;;
+ $pos -= $n while $pos >= $n;
+}
+
+say join(',',@nodes);
+
+say $nodes[0] * $nodes[1];