# Given a string s, sort it in decreasing order based on the frequency of the characters. # The frequency of a character is the number of times it appears in the string. # Return the sorted string. If ...

# Given an integer array nums of 2n integers, group these integers into n pairs (a1, b1), (a2, b2), ..., (an, bn) such that the sum of min(ai, bi) for all i is maximized. Return the maximized sum. # ...