Having the answers before you submit as a sanity check or verification helps you solidify your thinking.

If their answer differs from yours, you re-vet to find your error or theirs. If their answer matches, you're comfortable with the work you've done.

Having the answers after you've submitted only serves to highlight those sorts of problems as things you've gotten wrong.

I'm not asking for your answers, just saying I'm thinking about posting mine when I get em. In spoiler tags.