If you're a Java programmer, you want to be aware of this: String.substring() just went from O(1) to O(n)!

If you're a Java programmer, you want to be aware of this: String.substring() just went from O(1) to O(n)!
http://java-performance.info/changes-to-string-java-1-7-0_06/

Comments

  1. Lars Clausen5 December 2013 at 07:43

    Writing your own String implementation is practically impossible, since String is a final class, so you'd have to rewrite everything that uses a string. Which is roughly everything.

    It's for security, you know.

    ReplyDelete
  2. Troels Bjerre Lund5 December 2013 at 08:33

    Sure, your implementation will not mesh with any existing code, but there are cases where it is worth it. Sometimes, you also need a String implementation that can do concatenation in constant time. This shouldn't be default behavior, but some apps get a performance boost by it.

    ReplyDelete
  3. Lars Clausen5 December 2013 at 08:48

    True, but then it's more like a rope or twine or cord or something, rather than a string.

    ReplyDelete

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