#Data Structures

What is a doubly-linked list (DLL), and what are its applications? Describe the structure and how it differs from singly-linked lists.

Given a list of strings, find the most frequent element and store it in the most appropriate data structure. Consider the efficiency of your solution.

Solve a medium level DSA problem that requires a solid understanding of algorithms and data structures. Describe your approach in detail.

Write a function to reverse a singly linked list. The function should take the head of the list as input and return the new head after reversal. For example, given the list 1 -> 2 -> 3 -> NULL, it should return 3 -> 2 -> 1 -> NULL.

Implement a Min Stack that includes the ability to retrieve the minimum element in O(1) time. The stack should support standard stack operations: push, pop, and top.