Determine the fewest character replacements needed to transform one string into an anagram of another. Essentially, find the minimum steps to make two strings have the same character frequencies.

Find the smallest substring within a larger string that contains all the characters of a target string. You need to locate the minimum window that satisfies this condition.

Find the length of the longest 'mountain' (increasing then decreasing sequence) within an array of numbers. The mountain must have at least 3 elements.

Design a data structure that supports insertion, deletion, and random element retrieval, all in constant time on average. You'll need to handle edge cases carefully to achieve O(1) complexity.

Given a grid representing land and water, count the number of distinct islands. An island is formed by connected land cells.

You're given a list of asteroids, each with a size and direction (positive is right, negative is left). Figure out which asteroids will survive after all collisions happen.

Find the k most frequent elements in a given array of numbers. Return the top k elements based on their frequency.

Find the maximum number of non-overlapping palindrome substrings you can create from a given string. Each substring must be a palindrome, and no two substrings can overlap.

Find the smallest subarray within a given array that has the same degree as the entire array. The degree is defined as the highest frequency of any element.

You are given k sorted lists. Combine all of their elements into a single sorted list and return it.

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.

Design a data structure that acts as a Least Recently Used (LRU) cache. Implement methods to get and put key-value pairs, evicting the least recently used entry when the cache is full.

Convert a Roman numeral string into its corresponding integer value. The input string will represent a valid Roman numeral.

Imagine people in a circle, eliminating every kth person. Determine who is the last person remaining after this process.

You are given a list of meeting time intervals. Determine the minimum number of conference rooms required to accommodate all the meetings without any overlap.

Find the number of palindromic substrings within a given string. Consider each single character and repeated characters as a substring.

Find the number of contiguous subarrays within a given array whose product is strictly less than a target value k. The goal is to efficiently count these subarrays by considering the product of their elements.