RogerBW's Blog

I’ve been doing the Weekly Challenges. The latest involved combinations and counting. (Note that this ends today.)

Task 1: Complete Day

You are given an array of integers, @hours.

Write a script to return the number of pairs that forms a complete day.

A complete day is defined as a time duration that is an exact multiple of 24 hours.

A pretty strraightforward two-parter here:

(1) generate each possible 2-combination (using library functions)

(2) check all combination sums for mod 24 == 0.

Lua:

function completeday(a)
   local out = 0
   for _, c in combinations(a, 2) do
      if (c[1] + c[2]) % 24 == 0 then
         out = out + 1
      end
   end
   return out
end

Task 2: Maximum Frequency

You are given an array of positive integers, @ints.

Write a script to return the total frequencies of elements in the given array such that those elements all have the maximum frequency.

And this one falls into three parts:

(1) get list into a freqency-counted list

(2) determine the maximum freqency

(3) see how many times that maximum frequency occurs.

Raku:

sub maximumfrequency(@a) {

Build the counted list:

  my %c;
  for @a -> $n {
    %c{$n}++;
  }

Find maximum frequency:

  my $mx = %c.values.max;

Count occurrences.

  return $mx * %c.values.grep({$_ == $mx}).elems;
}

Full code on github.