Medium

Problem You are working at an accounting firm and need to combine financial reports from two different departments, let’s say Marketing and Sales. These reports are provided to you in electronic format as linked lists of numbers. Each node in the linked list represents one digit of a larger number. The digits are arranged in reverse order because this is how they were stored in their original databases. Your task is to create a combined financial report by adding the numbers from both departmental reports. This requires you to traverse both linked lists, starting from the head (leftmost) node and moving towards the tail (rightmost). As you add the digits of each position, you also need to carry over any value resulting from the addition that is greater than 9 (i.e., tens place). This new carried-over value will become the next digit in the combined number. ...

Problem You’re a shop sign designer, designing a dynamic digital sign for a trendy food truck called Burrito Truck. To catch the attention of hungry passersby, you want to display the restaurant’s name in a visually striking zigzag pattern. P A H N A P L S I I G Y I R And then read line by line: "PAHNAPLSIIGYIR " Write the code that will take a string and make this conversion given a number of rows: ...

Problem Imagine you’re working with DNA sequences to uncover regions critical for enzyme binding and gene regulation. Your task is to develop an algorithm that, given a DNA strand represented as a string (e.g., “AGCTTTCGA”), locates and returns the longest contiguous palindromic segment. Identifying this region is key because palindromic sequences in DNA often serve as specific recognition sites for enzymes and play a role in forming secondary structures that influence biological functions. ...

Problem You are building a news collection app that fetches articles from various sources and presents them in a summarized form to users, so they can quickly grasp the main points without having to read the full article. One important feature of your app could be to remove duplicate words or phrases from these summaries while still retaining as much information as possible. Example 1: Input: s = “xyzxyzyy” Output: 3 Explanation: The answer is “xyz”, with the length of 3. ...

Problem You work for a financial services company that handles transactions involving 32-bit signed integer amounts. Your goal is to enhance security by implementing an additional check: reverse the digits of a given transaction amount to create a new reference code. If reversing the digits results in a value outside the valid range of transaction amounts, which lies between -2,147,483,648 and 2,147,483,647, then return a code indicating the operation is invalid. Otherwise, return the reversed amount as the reference code. Assume the environment does not allow you to store 64-bit integers (signed or unsigned). ...