Sort a String by Frequency
Sort a string by the frequency of its characters.
Input: s = "cccaaa"
Output: "cccaaa" or "aaaccc"
Explanation: Both 'c' and 'a' appear three times, so sorting them by descending frequency keeps them grouped equally.

Question

Sort a string by the frequency of its characters.

Input: s = "cccaaa"

Output: "cccaaa" or "aaaccc"

Explanation: Both 'c' and 'a' appear three times, so sorting them by descending frequency keeps them grouped equally.