THE WEEKLY CHALLENGE - 244

https://theweeklychallenge.org/blog/perl-weekly-challenge-244/

Table of Contents

Task 1 - Count Smaller

Exploring the 'Count Smaller' Challenge Across Languages

Imagine a simple yet intriguing challenge: Given an array of integers, calculate how many numbers are smaller than the current number at each position. Sounds straightforward, right? But as you delve into solving this in different programming languages - namely Perl, Python, and Raku - you uncover the nuances and elegance of each.

The Task: We have an array, say [8, 1, 2, 2, 3]. Our goal? To output an array where each element is the count of numbers smaller than the element at that index in the input array. The expected output for our example is [4, 0, 1, 1, 3].

Python Approach: Python, known for its readability, allows us to solve this with a clean and concise nested loop. By iterating over the array and comparing each element with others, we count the smaller elements efficiently. This approach, while not the most optimized, shines in its simplicity and clarity.

def count_smaller(nums):
    return [sum(1 for j in nums[i+1:] if j < num) for i, num in enumerate(nums)]

Perl's Take: Perl, with its reputation for text processing, also handles array manipulation adeptly. The Perl solution mirrors Python's logic but in a more 'Perlish' way. Using regular loops and array indexing, it's a testament to Perl's enduring utility in various tasks.

sub count_smaller {
    my @nums = @_;
    my @result;
    for my $i (0 .. $#nums) {
        my $count = grep { $_ < $nums[$i] } @nums;
        push @result, $count;
    }
    return @result;
}

Raku, the Perl's Sibling: Raku (formerly known as Perl 6) brings a more modern take. It simplifies the task with its expressive syntax, leveraging features like gather/take and array slicing, showcasing its capabilities in handling complex tasks with elegance.

sub count-smaller(@nums) {
    return gather for @nums -> $num {
        take @nums.grep({ $_ < $num }).elems;
    }
}

Task 2 - Group Hero

The Challenge: Given an array of integers, we need to find the sum of the powers of all possible combinations. The twist? The power is the square of the largest number in a combination, multiplied by the smallest.

Breaking It Down:

Generate Combinations: We explore every possible grouping, from single elements to the entire array. Compute Power: For each group, we find the maximum and minimum values, then multiply the square of the max by the min. Sum It Up: We add up these calculated powers to get our final answer. Perl, Python, and Raku to the Rescue: Each language offers unique tools to tackle this problem, from Perl's Math::Combinatorics to Python's itertools, and Raku's elegant built-in methods.

Real-World Application: This isn't just an academic exercise. Such algorithms are pivotal in fields like data analysis, where understanding different combinations and their impacts can lead to groundbreaking insights.

The Takeaway: Combinations in programming are a powerful concept. Understanding how to manipulate and analyze them can open doors to solving complex problems in innovative ways. 🚀