What is the time complexity of HashMap.containsKey() in java?

by

From the API doc ofHashMap:

This implementation provides constant-time performance for the basic
operations (get and put), assuming the hash function disperses the
elements properly among the buckets.

Since containsKey() is just a get() that throws away the retrieved value, it’s O(1) (assuming the hash function works properly, again).

More Related Contents:

  1. Showing the order of growth of the function
  2. Is a Java hashmap search really O(1)?
  3. Java HashMap performance optimization / alternative
  4. Theoretical limit for number of keys (objects) that can be stored in a HashMap?
  5. Why are immutable objects in hashmaps so effective?
  6. Hashmap vs Array performance
  7. Get List<K> from HashMap<K, V> where V is instance of I [closed]
  8. Does use of final keyword in Java improve the performance?
  9. Why is creating a Thread said to be expensive?
  10. .toArray(new MyClass[0]) or .toArray(new MyClass[myList.size()])?
  11. Swing animation running extremely slow
  12. is the Java HashMap keySet() iteration order consistent?
  13. Faster alternatives to Java’s reflection [closed]
  14. Is it safe to get values from a java.util.HashMap from multiple threads (no modification)?
  15. Performance difference between Java 8 lambdas and anonymous inner classes
  16. Iterating through a LinkedHashMap in reverse order
  17. Most efficient Java primitive collections library [closed]
  18. Know of any Java garbage collection log analysis tools? [closed]
  19. When and how does HashMap convert the bucket from linked list to Red Black Trees? [duplicate]
  20. How can I sort Map values by key in Java?
  21. Accessing the last entry in a Map
  22. Shortcut for adding to List in a HashMap
  23. What is the quantitative overhead of making a JNI call?
  24. Java split String performances
  25. Time complexity of contains(Object o), in an ArrayList of Objects
  26. ArrayList vs. Vectors in Java if thread safety isn’t a concern
  27. HQL joined query to eager fetch a large number of relationships
  28. Recycler view – resizing item view while scrolling (for carousel like effect)
  29. Measuring time spent on GC
  30. Try Catch Performance Java

Leave a Comment