Solve Python Challenges: Reverse String, Palindrome, Fibonacci, Unique List
Company: OneMain Financial
Role: Data Scientist
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Onsite
##### Scenario
Live coding round – four quick Python exercises
##### Question
Implement a function that reverses a string in-place. Write code that returns True if a given integer is a palindrome, False otherwise. Generate the n-th Fibonacci number iteratively without recursion. Given an unsorted list of integers, return a new list containing only the unique values, preserving original order.
##### Hints
Each task should run in O(n) time or better, and you may not import external libraries.
Overview: This question evaluates fundamental programming skills such as string manipulation, algorithmic reasoning for numeric patterns, sequence generation, and data deduplication within the Coding & Algorithms domain for a Data Scientist role.
Given an unsorted list of integers nums, return a new list containing each distinct value exactly once, preserving the order of their first occurrence. Do not sort or otherwise reorder the input.
Constraints
- 0 <= len(nums) <= 200000
- -1000000000 <= nums[i] <= 1000000000
- Preserve the order of first occurrences
- Do not sort the input
- Target time complexity: O(n)
- Target space complexity: O(n)
- Do not import external libraries
Hints
- Use a hash set to track which values have been seen.
- Append a number to the result only the first time it appears.
- Avoid sorting; membership checks in a set are O(1) on average.