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+#!/usr/bin/perl
+#
+# Challenge 1: "Create a script that accepts two strings, let us call it,
+# "stones" and "jewels". It should print the count of "alphabet" from the
+# string "stones" found in the string "jewels". For example, if your stones
+# is "chancellor" and "jewels" is "chocolate", then the script should print
+# "8". To keep it simple, only A-Z,a-z characters are acceptable. Also
+# make the comparison case sensitive."
+# 
+# My notes: Not very clearly defined, but to get 8 in the example, I infer
+# that it means "form a set from the first string (thus ignoring repeated
+# letters) and then count up how many occurrences of each letter in that set
+# in the second word".  That's trivial, let's do it.
+# 
+
+use v5.10;	# to get "say"
+use strict;
+use warnings;
+
+die "Usage: ch-1.pl WORD1 WORD2\n" unless @ARGV == 2;
+
+my $word1 = shift;
+my $word2 = shift;
+
+# form a set of the letters in $word1 (case sensitive)
+my %set = map { $_ => 1 } split(//, $word1);
+
+# form a bag of the letters in $word2
+my %bag;
+map { $bag{$_}++ } split( //, $word2 );
+
+# now, count up sum of bag elements for everything in set
+my $t = 0;
+foreach my $letter (keys %set)
+{
+	$t += $bag{$letter} if defined $bag{$letter};
+}
+say $t;