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javacollectionsbinary-search
Suemayah Eldursi
Suemayah Eldursi

Reputation: 1009

What algorithm does java contains() method use?

I want to search efficiently for an object in a HashSet that I have.

I would like to know if the contains() method which is defined on java collections uses binary search or not? Or should I write my own binary search algorithm?

Upvotes: 3

Views: 1494

Answers (1)

Eugene
Eugene

Reputation: 120968

The general search complexity in a HashSet is O(1) - meaning it is constant. Writing your own? Better then this?

You absolutely can look at the sources, understand that a HashSet is actually a HashMap internally; that it uses buckets and LinkedNodes and TreeNodes; understand how these work, etc etc. Or trust the implementation that is good and focus on other stuff; unless you honestly have a requirement for something faster.

Upvotes: 4

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