https://theweeklychallenge.org/blog/perl-weekly-challenge-328/

2 files changed, 65 insertions, 0 deletions

diff --git a/challenge-328/kjetillll/perl/ch-1.pl b/challenge-328/kjetillll/perl/ch-1.pl
new file mode 100644
index 0000000000..a5b617eee5
--- /dev/null
+++ b/challenge-328/kjetillll/perl/ch-1.pl
@@ -0,0 +1,49 @@
+sub f {
+    local $_ = pop;
+    1 while s{
+               (.?)
+               \?
+               (.?)
+             }
+             {
+               $1
+               .
+               ( grep /[^$1$2 ]/, 'a' .. 'z' )[0]
+               .
+               $2
+             }ex;
+    $_;
+}
+
+
+print f("a?z")     eq "abz"      ? "ok" : "err", "\n";
+print f("pe?k")    eq "peak"     ? "ok" : "err", "\n";
+print f("gra?te")  eq "grabte"   ? "ok" : "err", "\n";
+print f("a?????b") eq "ababacb"  ? "ok" : "err", "\n";
+print f("?a?")     eq "bab"      ? "ok" : "err", "\n";
+print f("?")       eq "a"        ? "ok" : "err", "\n";
+
+__END__
+
+For speedup, should it be needed, on very long inputs with many '?' chars
+and/or very many inputs, initialize once an @array or a %hash and replace
+this construct:
+
+( grep /[^$1$2 ]/, 'a' .. 'z' )[0]
+
+with either this:
+
+$array[ ord($1||'a') ][ ord($2||'a') ]
+
+or this:
+
+$array[ ord($1||'a') * 128 + ord($2||'a') ]
+
+or this if you prefer hashes and accept a little slower lookup than arrays:
+
+$hash{ $1 || 'a', $2 || 'a' }
+
+where the array/hash contains a possible pre-calculated letter for all
+26*26=676 possible combinations of the two a-z chars before and after the '?'
+and default to 'a' if the '?' are at the beginning or end of the string.
+
diff --git a/challenge-328/kjetillll/perl/ch-2.pl b/challenge-328/kjetillll/perl/ch-2.pl
new file mode 100644
index 0000000000..fb88fd4616
--- /dev/null
+++ b/challenge-328/kjetillll/perl/ch-2.pl
@@ -0,0 +1,16 @@
+use v5.10;
+
+sub f {
+    state $regex_list = join '|', map { uc.lc, lc.uc } 'a' .. 'z'; #Aa|aA|Bb|bB ... Zz|zZ
+    my $str = shift;
+    1 while $str =~ s/$regex_list//g;
+    $str
+}
+
+
+print f( "WeEeekly" ) eq "Weekly" ? "ok\n" : "err\n";
+print f( "abBAdD" )   eq ""       ? "ok\n" : "err\n";
+print f( "abc" )      eq "abc"    ? "ok\n" : "err\n";
+
+#'state' instead of 'my' inits $regex_list only once even though f() is called multiple times.
+#It also makes $regex_list invisible outside of sub f. Needs at least 'v5.10' for 'state' to be available.