Solution to task 1

1 files changed, 64 insertions, 0 deletions

diff --git a/challenge-180/jo-37/perl/ch-1.pl b/challenge-180/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..7187cfbfbb
--- /dev/null
+++ b/challenge-180/jo-37/perl/ch-1.pl
@@ -0,0 +1,64 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use experimental 'signatures';
+
+our ($tests, $examples);
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [STR]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+STR
+    string to be examined
+
+EOS
+
+
+### Input and Output
+
+say first_uniq(shift);
+
+
+### Implementation
+
+sub first_uniq ($str) {
+    # Count each character's occurrences.
+    my %cnt;
+    $cnt{$_}++ for split //, $str;
+    # Return the index of the first unique character.
+    $cnt{substr $str, $_, 1} == 1 && return $_ for 0 .. length($str) - 1;
+    # If there is no unique character in the string:
+    -1;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is first_uniq('Perl Weekly Challenge'), 0, 'example 1';
+        is first_uniq('Long Live Perl'), 1, 'example 2';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        is first_uniq('aa'), -1, 'no unique character';
+        is first_uniq(''), -1, 'empty string';
+        is first_uniq('aa0'), 2, 'find zero';
+	}
+
+    done_testing;
+    exit;
+}