Why is processing a sorted array faster than an unsorted array? (stackoverflow.com)

15 points by Hellcat 12y ago ↗ HN

5 comments

[ 3.2 ms ] story [ 19.4 ms ] thread

deletes 12y ago ↗

Already posted about 14(!) times last year.

https://www.hnsearch.com/search#request/submissions&q=Why+is...

Discussion: https://news.ycombinator.com/item?id=4637196

todd3834 12y ago ↗

I've been reading hacker news, daily, for years and this is my first time noticing it. Thanks for posting!

[dead] TempleOSV2 12y ago ↗

I learned only about two things in my numeric methods class that I remember as useful.

Sort before adding tiny values.

georgehaake 12y ago ↗

Java 3.326788s, C++ 8.46879s on my machine. This is interesting. Code seems analogous.

deletes 12y ago ↗

Code in the question is a bad test example. As the answer shows, different compilers can optimize the code in different ways to make the outer loop almost meaningless. A better test would have 100000 different arrays to test.

Did you enable optimizations in C++ and disable adaptive optimization in java?