CODEWITHSUNDEEP
javahashmapset
Matt
Matt

Reputation: 501

Inserting into hashmap, accounting for duplicates in Set?

So to my knowledge duplicates are not allowed in a Java set. Why then in this code snippet does the code seem to try to take account of duplicates?

public static Subarray findSmallestSubarrayCoveringSet(List<String> paragraph,Set<String> keywords) {

   Map<String, Integer> keywordsToCover = new HashMap<>();
   for (String keyword : keywords) {
      keywordsToCover.put(keyword,
      keywordsToCover.containsKey(keyword)? keywordsToCover.get(keyword) + 1: 1);
   }

Why not just have keywordsToCover.put(keyword,1) inside the for loop?

Upvotes: 6

Views: 49

Answers (2)

Cardinal System
Cardinal System

Reputation: 3430

You are correct, as it says in the Javadoc:

a Set is a collection that contains no duplicate elements.

Who ever wrote that sample is unaware of this fact.

There will never be a case where keywordsToCover.containsKey(keyword) returns true, unless keywordsToCover is initialized (outside of the method) as static and is not reconstructed every time findSmallestSubarrayCoveringSet is called.

Upvotes: 0

Ousmane D.
Ousmane D.

Reputation: 56489

You're correct here, the call keywordsToCover.containsKey(keyword) would never be true. It just seems that whoever wrote the code didn't understand what is the purpose of a Set or they have mistakenly done so (though that's unlikely). thus just the call keywordsToCover.put(keyword,1) would suffice.

Upvotes: 1

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