You can declare a variable "size" for keeping the word's length.
Using the length() method in a loop may be quite a drag for your pc.

Would be a lot better to use StringBuilder, that thing is no joke 100 times faster

No, time complexity is still O(n * (n + n + n)) = O(n²).

Concatenating strings with += in a loop can have a time complexity of O(n^2)!!!!
Adding this all together, the overall time complexity is O(n^3).

it's soo fucking clever man, nice one !

Yes

too slow...

"If you use an array to store the number of occurances …"
it sound to me like a histogram, and for that a hash map would be a better data structure.

Will it work with string containing only one cymbol?

beautiful

This is some beautiful code!

I agree this is a cool solution but far from following best practices. Runtime complexity for this solution is O(N^2) which can easily be solved in O(N)

Cool solution!

Clever solution, but you should use here StringBuilder object to create final string for better performance.

TIL that lastIndexOf exists and I've looked at the String API dozens of times haha