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#!/usr/bin/env perl
use strict;
use warnings;
use feature qw'say state signatures';
no warnings qw'experimental::signatures';
# TASK #2 › Rob The House
# Submitted by: Mohammad S Anwar
#
# You are planning to rob a row of houses, always starting with the first and moving in the same direction. However, you can’t rob two adjacent houses.
#
# Write a script to find the highest possible gain that can be achieved.
# Example 1:
#
# Input: @valuables = (2, 4, 5);
# Output: 7
#
# If we rob house (index=0) we get 2 and then the only house we can rob is house (index=2) where we have 5.
# So the total valuables in this case is (2 + 5) = 7.
#
#
# Example 2:
#
# Input: @valuables = (4, 2, 3, 6, 5, 3);
# Output: 13
#
# The best choice would be to first rob house (index=0) then rob house (index=3) then finally house (index=5).
# This would give us 4 + 6 + 3 =13.
use List::Util qw(all reduce sum0);
run() unless caller();
sub run() {
my @valuables = @ARGV;
die "Invalid input\n" unless all { m/^-?\d+$/ } @valuables;
say rob_house(@valuables);
}
sub rob_house (@valuables) {
my @tours = plan_tours($#valuables);
my $best_tour = reduce sub {
my @tour = @$b;
my $tour_value = sum0 map { $valuables[$_] } @tour;
if ( $tour_value > $a->{value}
|| $tour_value == $a->{value} && @tour < @{ $a->{tour} } )
{
return {
value => $tour_value,
tour => [@tour],
};
}
return $a;
}, { value => 0, tour => [] }, @tours;
return $best_tour->{value};
}
sub plan_tours ( $max, $cur = 0 ) {
return [] if $cur > $max;
my @paths = (
( map { [ $cur, @$_ ] } plan_tours( $max, $cur + 2 ) ),
plan_tours( $max, $cur + 1 )
);
return @paths;
}
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