/*Given an integer array nums sorted in non-decreasing order, remove some duplicates in-place such that each unique element appears at most twice. The relative order of the elements should be kept the ...

Explanation: Total number of unique elements are 3, i.e[1,2,3] and Therefore return 3 after assigning [1,2,3] in the beginning of the array. Explanation: Total number of unique elements are 4, i.e[1,2 ...

Automatically sorted: When elements are added to a TreeSet, they are automatically sorted in ascending order. Does not allow duplicates: If you try to add an element that already exists, it will be ...