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#!/usr/bin/env perl
###########################################################################
# script name: ch-1.pl #
# #
# https://github.com/user-person #
# #
# https://perlweeklychallenge.org/blog/perl-weekly-challenge-054/ #
# #
# kth Permutation Sequence #
# Write a script to accept two integers n (>=1) and k (>=1). #
# It should print the kth permutation of n integers. #
# For more information, please follow the wiki page. #
# https://en.wikipedia.org/wiki/Permutation#k-permutations_of_n #
# For example, n=3 and k=4, #
# the possible permutation sequences are listed below: #
# #
# 123 #
# 132 #
# 213 #
# 231 #
# 312 #
# 321 #
# The script should print the 4th permutation sequence 231. #
# #
###########################################################################
use strict;
use warnings;
use diagnostics;
use FindBin;
use List::Permutor;
sub msgExit {
print $FindBin::Script . " requires 2 arguments. The first argument to determine the sequence ( 1 >= ),
The second argument to determine which entry to print. Both arguments should be >= 1 .\n";
exit(1);
}
msgExit if scalar @ARGV != 2;
my $n = $ARGV[0];
my $k = $ARGV[1];
if ( $n =~ m{\A\d+\Z} and $k =~ m{\A\d+\Z} ) {
if ($n < 1 or $k < 1) {
msgExit;
}
} else {
msgExit;
}
my @sequence = 1 .. $n-1;
my $perm = new List::Permutor @sequence;
my $kth = 1;
my $failure++;
LOOP:
while (my @set = $perm->next) {
if ( $kth++ == $k) {
print @set, "\n";
$failure--;
last LOOP;
}
}
print "There is no '$k'-th number in the '$n sequence'.\n" if $failure;
endHandler() if $reporting || $logging; # TO CLEAN UP, AND CLOSE LOG ENTRIES
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