#!/usr/bin/perl

$filename = "18.txt";

open(FILE, $filename);
@data = <FILE>;
close(FILE);

$sum = 0;
$sumb = 0;

foreach $line (@data) {
        $line =~ s/[^0-9\+\*\(\)]*//sgi; # Condition the input
        $sum = $sum + domath($line); #part1
        $sumb = $sumb + domathb($line); #part2
}

print "P1: ".$sum."\n";
print "P2: ".$sumb."\n";



sub domath() {

        my $inp = $_[0];
        my $s = "";
        my $p = "";
        my $matha = "";
        my $mathb = "";
        my $newinp;

while ($inp =~ m/\(([^()]+)\)/) { #Run innermost parenthesis first
        $s = domath($1);
        $p = $1;
        $p =~ s/\(/\\\(/sgi;
        $p =~ s/\)/\\\)/sgi;
        $p =~ s/\+/\\\+/sgi;
        $p =~ s/\*/\\\*/sgi;
        $inp =~ s/\($p\)/$s/; #Replace inner parenthesis with result
}

while ($inp =~ m/([+*])/) { #No parenthesis left - run math parser until no operators are left.

        $char = $1;
        $matha = $inp;
        $matha =~ s/^(\d+)(.*)$/$1/; #Leftmost digit
        $mathb = $inp;
        $mathb =~ s/^(\d+)[+*](\d+)(.*)$/$2/; #Leftmost digit after operator

        if ($char eq "+") {
                $newinp = $matha + $mathb;
        }
        else
        {
                $newinp = $matha * $mathb;
        }

        $char =~ s/\+/\\\+/sgi;
        $char =~ s/\*/\\\*/sgi;

        $inp =~ s/$matha$char$mathb/$newinp/; #Replace expression with result.
        }

return $inp;
}


sub domathb() {

my $inp = $_[0];
my $s = "";
my $p = "";
my $matha = "";
my $mathb = "";
my $newinp;


while ($inp =~ m/\(([^()]+)\)/) { # same as before - run inner parenthesis first
        $s = domathb($1);
        $p = $1;
        $p =~ s/\(/\\\(/sgi;
        $p =~ s/\)/\\\)/sgi;
        $p =~ s/\+/\\\+/sgi;
        $p =~ s/\*/\\\*/sgi;
        $inp =~ s/\($p\)/$s/; #replace inner parenthesis with result
}

while ($inp =~ m/([+])/) { # Math parser for + only - run until theres no +'s left

        $matha = $inp;
        $matha =~ s/^(.*?)([0-9]+)\+([0-9]+)(.*?)$/$2/; # Digits before +
        $mathb = $inp;
        $mathb =~ s/^(.*?)([0-9]+)\+([0-9]+)(.*?)$/$3/; # Digits after +

        $newinp = $matha + $mathb;

        $inp =~ s/$matha\+$mathb/$newinp/; #Replace expression with result
}

while ($inp =~ m/([*])/) { # Math parser for * only - run until theres no *'s left

        $matha = $inp;
        $matha =~ s/^(.*?)([0-9]+)\*([0-9]+)(.*?)$/$2/; # Digits before *
        $mathb = $inp;
        $mathb =~ s/^(.*?)([0-9]+)\*([0-9]+)(.*?)$/$3/; # Digits after *

        $newinp = $matha * $mathb;

        $inp =~ s/$matha\*$mathb/$newinp/;
}

return $inp;
}