Perl Weekly Challenge 95: palindrome numbers and stacks
One way to let me improve my knowledge about Raku (aka Perl 6) is to implement programs in it. Unluckily, I don’t have any production code to implement in Raku yet (sob!). So, why not try solving the Perl Weekly Challenge tasks?In the following, the assigned tasks for Challenge 95.
My eyes…
It’s hard.Period.
I have another medical examination this week, and I hope something better will arise.
PWC 95 - Task 1
The first task is very simple in Raku: find out if a number is palindrome.It does suffice to create a
MAIN function that accepts only an integer number. After that, it is simply required to check the stringified version of the number is the same as its flipped (i.e., reversed) string:
sub MAIN( Int :$N = 1 ) {
say ~$N == ~$N.flip ?? '1' !! '0';
}
PWC 95 - Task 2
The second task was the implementation of a Stack, that can be easily achieved with the usage of arrays:
class SimpleStack {
has Int @!elements;
submethod BUILD {
@!elements = Array.new;
}
method push( Int $n ) { @!elements.push: $n; }
method pop() { @!elements[ @!elements.elems - 1 ]:delete; }
method top() { @!elements.reverse[ 0 ]; }
method min() { @!elements.min; }
method print() { say $_ for @!elements.reverse; }
}
In this way, every
push appends to the end of the array the last value, and therefore the top is the first element of the reversed array, while the min is the overall mimimum value within the array.
The pop operation is implemented by means of deleting the last element in the array (that is the first element in the stack).
Producing a
MAIN to represent the task workflow is therefore really simple:
sub MAIN() {
my SimpleStack $stack = SimpleStack.new;
$stack.push(2);
$stack.push(-1);
$stack.push(0);
$stack.pop; # removes 0
say $stack.top; # prints -1
$stack.push(0);
say $stack.min; # prints -1
}