Problem (verbatim) Design a data structure that supports insert, delete, search, and getRandom in constant time. Use a dynamic array + hash map (value → index). The VOprep team has long accompanied candidates through various major company OAs and VOs, including Tiktok, Google, Amazon, Citadel, SIG, providing real-time voice assistance, remote practice, and interview pacing reminders to…

Given an array of positive integers nums and an integer k,return true if nums has a continuous subarray whose sum equals k. Examples: Since all numbers are positive, we can use a sliding window: This works in O(n) because the two pointers only move forward. The VOprep team has long accompanied candidates through various major company OAs…

You are given a string s.You can convert s to a palindrome by adding characters in front of it.Return the shortest palindrome you can form by performing this transformation. Input:s = “aacecaaa” Output:”aaacecaaa” The task is to create the shortest palindrome by adding characters only to the front of the given string. Main idea: Optimal…

Given a string s, return true if it is a palindrome, or false otherwise. Input:s = “aba” Output:true This problem checks whether a string is a palindrome, meaning it reads the same forward and backward. Typical approach: Runs in O(n) time and O(1) space (two-pointer approach). The VOprep team has long accompanied candidates through various major company…

A unique character is one that appears only once in a string.Given a string consisting of lowercase English letters only, return the index of the first occurrence of a unique character in the string using 1-based indexing.If the string does not contain any unique character, return -1. Example:s = “statistics”The unique characters are [a, c],…

Parentheses strings are strings containing only the characters ‘(‘ and ‘)’.A parentheses string is considered balanced when its opening parentheses align with its closing parentheses.For example, “()” and “(())” are balanced, while “)(“, “())(” are not. Given a string consisting of the same number of opening and closing parentheses, determine the minimum number of character…

You are running a car dealership and currently have 2 employees.We are going to be building a basic function to deal with customers booking appointments with your employees. You have the following constraints: Implement a DealershipScheduler class with the following method: Return true if you can book an appointment for these times, and false if…

You’re building a daily calendar app and need to display all of the day’s events in the right location on the screen, but it needs to be given a bounding box.We need to take a list of events happening that day and produce a list of bounding boxes to be drawn. An event has: Example…