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#+TITLE: Challenge 080

* Task 1 - Smallest Positive Number Bits
You are given unsorted list of integers =@N=.

Write a script to find out the smallest positive number missing.
** Perl
- Initial version didn't check for =1=, I might have assumed that it was
  accounted for in this line =print "1\n" and exit 0 if $sorted[$#sorted]
  < 1;=.

- This was pointed out by [[https://octodon.social/@polettix]] -
  [[https://tilde.zone/web/statuses/104981669595493301#]]

- Program: [[file:perl/ch-1.pl]]

We take input from =@ARGV=, sort it & remove all inputs less than 1. We
check if the smallest positive number is 1. We filter repeated inputs
using =%hash=.
#+BEGIN_SRC perl
my %hash;
%hash = map { $_ => 1 } @ARGV;

my @sorted = sort { $a <=> $b } keys %hash;

# Print 1 if there are no positive numbers in @sorted.
print "1\n" and exit 0 if $sorted[$#sorted] < 1;

while (my $arg = shift @sorted) {
    next if $arg < 1;
    print "1\n" and exit 0 unless $arg == 1;
    last;
}
#+END_SRC

Now we are sure the smallest positive number is not 1 & =@sorted= doesn't
contain any number less than 2.

We loop from =2 ... $sorted[$#sorted] + 1= & then over =@sorted= array. The
first number from the array is dropped if it's equal to =$num=. If not
then =$num= is the smallest positive number, we print it & exit the =MAIN=
loop.

This won't print the smallest positive number if the user passed
consecutive set of numbers, we just add =print "$num\n"= at the end to
cover this case.
#+BEGIN_SRC perl
MAIN: foreach my $num (2 ... $sorted[$#sorted] + 1) {
    foreach (@sorted) {
        shift @sorted and next MAIN if $num == $_;
        print "$num\n" and last MAIN;
    }
    # Print the last element if it was a continous series of positive
    # numbers.
    print "$num\n";
}
#+END_SRC
* Task 2 - Count Candies
You are given rankings of =@N= candidates.

Write a script to find out the total candies needed for all candidates.
You are asked to follow the rules below:

1. You must given at least one candy to each candidate.
2. Candidate with higher ranking get more candies than their mmediate
   neighbors on either side.
** Perl
- Program: [[file:perl/ch-2.pl]]

Giving at least one day to all candidates.
#+BEGIN_SRC perl
my $candies = scalar @ARGV;
#+END_SRC

Handling first & last index, we do this outside the loop to keep it
simple.
#+BEGIN_SRC perl
$candies++ if $ARGV[0] > $ARGV[1];
$candies++ if $ARGV[$#ARGV] > $ARGV[$#ARGV - 1];
#+END_SRC

Loop handles rest of the entries.
#+BEGIN_SRC perl
foreach my $index (1 ... $#ARGV - 1) {
    $candies++ if $ARGV[$index] > $ARGV[$index - 1];
    $candies++ if $ARGV[$index] > $ARGV[$index + 1];
}

print "$candies\n";
#+END_SRC