Solve three OA coding questions

You are given a 90-minute online assessment containing **three coding questions**. Implement solutions for all questions. --- ## Question 1: Group strings that are anagrams Given an array of strings `strs`, group the strings into lists where each list contains strings that are anagrams of each other. ### Input - `strs`: array of lowercase strings (may include duplicates) ### Output - A list of groups (each group is a list of strings). Order of groups and order within a group do not matter. ### Constraints (typical) - `1 <= len(strs) <= 10^4` - `0 <= len(strs[i]) <= 100` --- ## Question 2: Maximize an integer by swapping two digits at most once Given a non-negative integer `num`, you may swap **at most one pair** of its digits (or perform no swap). Return the **maximum value** you can obtain. ### Input - `num`: non-negative integer ### Output - Maximum integer achievable after at most one swap ### Constraints (typical) - `0 <= num <= 10^8` --- ## Question 3: Rank hotels by review sentiment and return top-k You are given: - A set of **positive keywords** and **negative keywords**. - A list of hotel reviews, each associated with a `hotel_id`. - An integer `k`. Compute each hotel’s total sentiment score by scanning all its reviews. ### Scoring rules - Tokenize each review into words by splitting on non-letter characters (punctuation and symbols are separators). - Comparison is **case-insensitive**. - For every word occurrence: - If the word is in the positive set: **+1** - If the word is in the negative set: **-1** - Otherwise: **0** - A hotel’s total score is the sum across all its reviews. ### Task Return the **top `k` hotel IDs** ranked by: 1. Higher total score first 2. If tied, smaller `hotel_id` first ### Input (one reasonable spec) - `positive_keywords`: string or list of words - `negative_keywords`: string or list of words - `hotel_ids`: array of integers, parallel to `reviews` - `reviews`: array of strings - `k`: integer ### Output - Array of `k` hotel IDs in sorted ranking order ### Constraints (typical) - `1 <= len(reviews) == len(hotel_ids) <= 10^5` - Total review text length up to ~`10^6` - `1 <= k <= number_of_distinct_hotels` ### Notes - If a hotel has multiple reviews, aggregate them. - If there are fewer than `k` hotels (in some variants), return all hotels sorted by the same rule.