Most Common Word

Problems
1

https://algo.monster/problems/most_common_word

2

A solution using PriorityQueue. It’s still O(n) as heapify is used:

public static String mostCommonWord(String paragraph, List<String> banned) {
        Queue<Map.Entry<String, Integer>> pq = new PriorityQueue<>((a, b) -> {
            return -a.getValue().compareTo(b.getValue());
        });
        
        Map<String, Integer> hm = new HashMap<>();
        
        String[] paragraphArray = paragraph.replaceAll("[^a-zA-Z ]", "").toLowerCase().split(" ");
        
        for (String word : paragraphArray) {
            if (!banned.contains(word)) {
                if (hm.containsKey(word)) {
                    hm.put(word, hm.get(word) + 1);
                } else {
                    hm.put(word, 1);
                }
            }
        }
        pq.addAll(hm.entrySet());
        Map.Entry<String, Integer> mostUsedWordEntry = pq.poll();
        return mostUsedWordEntry.getKey();
    }