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#!/usr/bin/perl
# https://perlweeklychallenge.org/blog/perl-weekly-challenge-012/
# Challenge #2
# Write a script that finds the common directory path, given a collection of paths and directory separator.
# For example, if the following paths are supplied.
# /a/b/c/d
# /a/b/cd
# /a/b/cc
# /a/b/c/d/e
# and the path separator is /. Your script should return /a/b as common directory path.
use strict;
use warnings;
use constant SEPARATOR => '/';
my $usage = "Usage: $0 <absolute-path-with-".SEPARATOR."-as-separator>\n";
die $usage unless @ARGV > 0;
foreach (@ARGV) {
die "'$_' is not an absolute path\n".$usage if(substr($_,0,1) ne SEPARATOR);
}
my @chosen = split SEPARATOR, shift @ARGV;
shift @chosen; #first element is empty
#Last common directory
my $lcd = @chosen;
#Compare each given absolute path with the first one
PATH: foreach my $path (@ARGV) {
my @dirs = split SEPARATOR, $path;
shift @dirs; #first element is empty
my $matches = 0;
my $upto = ($lcd <= @dirs) ? $lcd : @dirs;
--$upto; #last directory index to compare
#Compare directories between this path and the chosen one
for my $index (0 .. $upto){
last if ($dirs[$index] ne $chosen[$index]);
$matches++;
}
$lcd = $matches if ($matches < $lcd);
last PATH if ($lcd == 0); #avoid checking others
}
splice(@chosen,$lcd);
print 'Common directory path: /'.join(SEPARATOR, @chosen );
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