Help me to find any similar problems like this array problem

The input is an array of numbers (not sorted),we have to output the array consisting of these numbers in decreasing order of number of times a particular number appeared in the array.
E.g :-
In :- 2,4,2,1,5,4,3,2.
out:- 2,2,2,4,4,5,3,1.

Please help me in finding similar problems like this.
Thank You

you can google the same thing and can find more example
here is one leetcode question : - LeetCode

Thank you