I'm a frequent user of SO, but I find leetcode [1] much better when I just want to practice coding / problem solving. Their free account is more than enough to have some fun ;)

[1] https://leetcode.com/

I disagree. Leetcode and related sites have problem descriptions that are often vague or nonsensical. Just figuring out what the author is trying to say is more of a challenge than the actual program sometimes.

I feel exactly the same, I thought that it's because I'm not a native speaker, at least now I know that I'm not alone.