From b8d4ba46cfd21a36c9939ea950666141888a258b Mon Sep 17 00:00:00 2001
From: 冯昶 <fengchang@novel-supertv.com>
Date: Sun, 16 Jun 2019 00:53:13 +0800
Subject: challenge 012 #2

---
 challenge-012/feng-chang/perl5/ch-2.pl   | 27 +++++++++++++++++++++++++++
 challenge-012/feng-chang/perl5/paths.txt |  4 ++++
 challenge-012/feng-chang/perl6/ch-2.p6   | 17 +++++++++++++++++
 challenge-012/feng-chang/perl6/paths.txt |  4 ++++
 4 files changed, 52 insertions(+)
 create mode 100755 challenge-012/feng-chang/perl5/ch-2.pl
 create mode 100644 challenge-012/feng-chang/perl5/paths.txt
 create mode 100755 challenge-012/feng-chang/perl6/ch-2.p6
 create mode 100644 challenge-012/feng-chang/perl6/paths.txt

diff --git a/challenge-012/feng-chang/perl5/ch-2.pl b/challenge-012/feng-chang/perl5/ch-2.pl
new file mode 100755
index 0000000000..c3c26e5f79
--- /dev/null
+++ b/challenge-012/feng-chang/perl5/ch-2.pl
@@ -0,0 +1,27 @@
+#!/bin/env perl
+
+use Modern::Perl;
+use List::Util qw(reduce);
+
+sub common_prefix {
+    my ($a, $b) = @_;
+    my @a = split //, $a;
+    my @b = split //, $b;
+
+    my $r = '';
+    my $i = 0;
+    while ($a[$i] && $b[$i] && $a[$i] eq $b[$i]) {
+        $r .= $a[$i++];
+    }
+
+    return $r;
+}
+
+chomp(my @paths = <>);
+my $common_path = reduce { common_prefix($a, $b) } @paths;
+
+my @c = split //, $common_path;
+pop @c while $c[-1] ne '/';
+pop @c if @c > 1;
+
+say 'common directory path: ', join('', @c);
diff --git a/challenge-012/feng-chang/perl5/paths.txt b/challenge-012/feng-chang/perl5/paths.txt
new file mode 100644
index 0000000000..1427e2dbc8
--- /dev/null
+++ b/challenge-012/feng-chang/perl5/paths.txt
@@ -0,0 +1,4 @@
+/a/b/c/d
+/a/b/cd
+/a/b/cc
+/a/b/c/d/e
diff --git a/challenge-012/feng-chang/perl6/ch-2.p6 b/challenge-012/feng-chang/perl6/ch-2.p6
new file mode 100755
index 0000000000..1ea095468d
--- /dev/null
+++ b/challenge-012/feng-chang/perl6/ch-2.p6
@@ -0,0 +1,17 @@
+#!/bin/env perl6
+
+sub common_prefix(Str $a, Str $b) {
+    my @a = $a.comb;
+    my @b = $b.comb;
+
+    for 0..∞ -> $i {
+        last unless @a[$i].defined && @b[$i].defined && @a[$i] eq @b[$i];
+        LAST { return @a[0 .. $i - 1].join }
+    }
+}
+
+my @c = ([[&common_prefix]] 'paths.txt'.IO.lines).comb;
+@c.pop while @c[* - 1] ne '/';
+@c.pop if @c.elems > 1;
+
+say 'common directory path: ', @c.join;
diff --git a/challenge-012/feng-chang/perl6/paths.txt b/challenge-012/feng-chang/perl6/paths.txt
new file mode 100644
index 0000000000..1427e2dbc8
--- /dev/null
+++ b/challenge-012/feng-chang/perl6/paths.txt
@@ -0,0 +1,4 @@
+/a/b/c/d
+/a/b/cd
+/a/b/cc
+/a/b/c/d/e
-- 
cgit