#!/usr/bin/env perl
# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
#=============================================================================
# ch-2.pl
#=============================================================================
# Copyright (c) 2020, Bob Lied
#=============================================================================
# Perl Weekly Challenge 078 Task #2 > Left Rotation
#=============================================================================
# You are given an array @A containing positive numbers and @B containing one
# or more indices from @A.
# Write a script to left-rotate @A so that the number at the first index of @B
# becomes the first element in the array. Similary, left rotate @A again so
# that the number at the second index of @B becomes the first element in the
# array.
# Example 1:
# Input: @A = (10 20 30 40 50)
#        @B = (3 4)
# a) We left rotate the 3rd index element (40) in the @A to make it 0th index
# member in the array.
#   [40 50 10 20 30]
#
# b) We left rotate the 4th index element (50) in the @A to make it 0th index
# member in the array.
#   [50 10 20 30 40]
#
# Output:
#   [40 50 10 20 30]
#   [50 10 20 30 40] 

use strict;
use warnings;
use v5.30;

use feature qw/ signatures /;
no warnings qw/ experimental::signatures /;

use Getopt::Long;

sub Usage { qq(Usage: $0 "(a b c d e)" "(x y)" ) };

my $Verbose = 0;
GetOptions('verbose' => \$Verbose);

my $A = shift;  # In list form, "10,20,30"
my $B = shift;  # In list form, "3,4";

die Usage() unless $A && $B;

$A =~ s/[(),]/ /g;
my @A = split(" ", $A);

$B =~ s/[(),]/ /g;
my @B = split(" ", $B);

if ( $Verbose )
{
    say "\@A = (@A)\n\@B = (@B)";
}

my $lastA = $#A;

for my $pivot ( @B )
{
    my @rot = ( @A[ $pivot .. $lastA], @A[0..$pivot-1] );
    say "[ @rot ]";
}