Explore strings and arrays in Python, treating strings as character arrays, learn in-place and returning reverse and sort operations, and compare lists, tuples, and sets for mutability and uniqueness.

Transform input integer to a string, reverse the string using the reversed method, and compare to the original to determine if the number is a palindrome.

Develop a brute force approach to find the longest palindrome substring by generating all substrings, checking each for palindrome via reversal, and selecting the longest.

Discover how binary search finds an element in a sorted array by comparing with the middle value and narrowing the left and right bounds, achieving logarithmic time.

Master merge sort by dividing the list into two halves, sorting each half, and merging them back into a sorted whole, a fast, stable divide-and-conquer algorithm.

Explore quick sort, a divide and conquer algorithm that uses the median as pivot to partition the array into left and right subarrays, then recursively sort each side.

Learn how to find the minimum in a rotated sorted array by identifying the pivot and using a binary search with left, right, and middle indices.

Demonstrate an efficient integer square root using binary search. Compare mid squared to x, update left and right, and return the floor when no perfect square exists.

Solve the two sum problem on a sorted array by iterating elements and using binary search to find the complement for the target, returning 0 and 2 for 13.

Generate all valid strings of opening and closing parentheses for a given even n via recursion, building results by wrapping, extending at the ends, and removing duplicates.

Compute the minimum yearly subway cost from a 365-day 0/1 schedule using 1-, 7-, and 30-day passes. Use a memoized recursive dynamic programming approach to choose optimal passes.

Explore depth first search by visiting graph nodes, marking them visited, and using a stack to follow connected nodes. Understand the recursive pseudocode and the Python DFS implementation.

Count islands in an array of zeros and ones by dfs on each unvisited land cell, visiting connected land and marking it in place to avoid extra storage.

Model the rooms and keys as a graph starting with room 0, and use dfs to visit all rooms and verify reachability.

Approach the system design interview as a conversation, weigh tradeoffs on cost, speed, reliability, and maintainability, and prepare by researching the company and discussing caching and load balancing.

Learn a high-level system design approach to building a ride-hailing service, from requirements gathering and driver–rider flows to database design with geospatial sharding and scalability considerations.