Efficient java data structure to delete and retrieve information?

Question

I have a situation where I have need a data structure that I can add strings to. This data structure is very large.

The specific qualities I need it have are:

1. get(index)
2. delete a certain number of entries that were added initially when the limit exceeds.(LIFO)

I've tried using an ArrayList but the delete operation is o(n) and for a linkedList the traverse or get() operation will be o(n).

What other options do I have?

Answer 1

循环缓冲区 -在引擎盖下使用数组实现的缓冲 。

Answer 2

LinkedHashSet might be of interest. It is effectively a HashSet but it also maintains a LinkedList to allow a predictable iteration order - and therefore can also be used as a FIFO queue, with the nice added benefit that it can't contain duplicate entries.

Because it is a HashSet too, searches (as opposed to scans) can be O(1) if they can match on equals()

You can have a look at this question and this too.