[vishbar]

Due to the physical architecture of CPUs/etc., data structures that have "worse" asymptotic performance are often quite a bit faster than those with "better" performance. For example, iterating through a small array to find an item and test for existence is often quite a bit faster than using a hash set for the same operation.

[eru]

In the same vein, pre-processing your data via sorting on some carefully chosen keys can sometimes alleviate the need for purpose built data structures.

And because of caches, sorting can sometimes beat hashtables.

[dhsysusbsjsi]

Which is why I just use the standard library.

[eru]

Most languages have more than one data structure in their standard library.