Maybe 5x, with most of that increase being a handrolled associative array.

You also need at least dynamic string of some sort. Actually, I would estimate 20x - I was being kind with 10x. But feel free to prove me wrong.

So it turns out that factor is just over 2.5x: https://gist.github.com/saagarjha/00faa1963023206a8ccd987798.... You can split hairs about it being POSIX and inefficient or not checking all the errors, but it works and isn't really all that massive.

Why do you need a dynamic string of any sort for this problem?

(I think you estimated badly, for what it's worth.)

You'd need it to read words, unless you're using a libc function that does the allocation for you. (Not that you actually need a full string, realloc works just fine for the code I'm writing.)

Yeah, I just used strdup and strsep, like a C programmer. You don't need a dynamic string to count words.

:P