Find two numbers in a given array that add up to a specific target value, and return their indices. Essentially, you need to efficiently locate the pair that satisfies the sum requirement.

Given a string, find the most frequent character that appears earliest in the string. Return the length of the shortest substring that contains all occurrences of this character.

Find the number of elements in an array that appear with the highest frequency. Essentially, count how many times the most frequent number occurs.