Question

I have a map with about 100,000 pairs . Is there any way that i can speed up searching when using find(), given that the keys are in alphabetical order. Also how should i go about doing it. I know that you can specify a new comparator when you create the map. But will that speed up the find() function at all?

Thanks in advance.

[solved] Thanks a bunch guys i have decided to go with a vector and use lower and upperbound to “snip” some of the searching.

Also i am new here is there any way to mark this question as answered , or pick a best answer?

Answer 1

A different comparator will only speed up find if it manages to do the comparison faster (which, for strings will usually be pretty difficult).

If you’re basically inserting all the data in order, then doing the searching, it may be faster to use a std::vector with std::lower_bound or std::upper_bound.

If you don’t really care about ordering, and just want to find the data as quickly as possible, you might find that std::unordered_map works better for you.

Edit: Just for the record: the way you “might find” or “may find” those things is normally by profiling. Depending on the situation, it might be enough faster that it’s pretty obvious even in simple testing, so profiling isn’t really necessary, but if there’s (much) doubt, or you want to quantify the effect, a profiler is probably the right way to do it.