Solution to task 1

1 files changed, 31 insertions, 0 deletions

diff --git a/challenge-081/jo-37/perl/ch-1.pl b/challenge-081/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..61941ab415
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+++ b/challenge-081/jo-37/perl/ch-1.pl
@@ -0,0 +1,31 @@
+#!/usr/bin/perl
+
+use Test2::V0;
+
+# Find common base strings in two given strings.
+sub cbs {
+
+	# Combine both strings by joining them with a newline.
+	# The strings must not contain newlines.
+	local $_ = shift . "\n" . shift;
+
+	# Collect all common base strings.
+	# Note: "dot" does not match a newline here.
+	my @base;
+	m{
+		^ (.+?) \1*+ \n \1++ \z	# capture base string for both
+		(?{push @base, $1})		# collect captured base string
+		(*FAIL)					# force backtracking
+	}x;
+
+	@base;
+}
+
+is [cbs("abcdabcd", "abcdabcdabcdabcd")], ["abcd", "abcdabcd"],
+	"first example";
+
+is [cbs("aaa", "aa")], ["a"], "second example";
+
+is [cbs("abcabc", "abcdabcdabcd")], [], "no common base strings";
+
+done_testing;