#Arrays

Write a C# method that returns the second highest distinct number in an integer array. Input: `[10, 5, 20, 8, 20]` Output: `10` (since 20 is the highest and 10 is the next distinct value)

Given a list of integers, find all unique pairs whose sum is equal to 10. Once an element is used in a pair, it cannot be reused. Optimize your solution for time and space complexity.

Solve the Split Array problem focusing on prefix sums, array partitioning, and efficient counting, typically resolved using a binary search on the answer approach.

Two medium-difficulty Data Structures and Algorithms problems covering Arrays/Strings and Graphs.

Given an array containing only 0s, 1s, and 2s, sort the array in linear O(n) time and O(1) extra space.