[FEATURE REQUEST] Add TopKFrequentWords algorithm in strings package

[oleksii-tumanov]

What would you like to Propose?

The implementation returns the k most frequent words from an input array.
https://en.wikipedia.org/wiki/Top-k_problem

Test Case (feature demonstration)
Input:

String[] words = {"the", "day", "is", "sunny", "the", "the", "the", "sunny", "is", "is"};
int k = 4;

Expected output:

["the", "is", "sunny", "day"]

Issue details

Algorithm details:

• Input: array of words String[] words and integer k.
• Output: list of the top k most frequent words.
• Ordering:
  • Higher frequency first.
  • If frequencies are equal, lexicographically smaller word first.
• Behavior:
  • If k == 0 or input array is empty, return empty list.
  • If k is greater than number of unique words, return all unique words in ranked order.
• Validation:
  • Throws IllegalArgumentException when:
    • words is null
    • k < 0
    • any element in words is null

Additional Information

No response

[oleksii-tumanov]

PR #7297