"noone", "no one" or "no-one"?
Solution 1:
"no one" is the correct one.
noone is the common misspelling of "no one".
"Noone" is formed for consistency with "nobody", and also its opposites "anyone" and "everyone", but it is still considered nonstandard because of the doubled vowels creating a temptation to read and pronounce it as "noon" (/nuːn/).
On the other hand, no-one is the alternative spelling of "no one". I don't think it's widely used.