## Coding questions (solve both) ### 1) First non-repeating character Given a string `s`, return the **first character that appears exactly once** in the string. - If no such character exists, return an empty value (e.g., `""`) or a special marker such as `None`/`null`. **Input:** `s` (string) **Output:** the first non-repeating character (or empty marker) **Constraints (typical):** - `1 <= len(s) <= 10^5` - `s` may contain letters (assume ASCII unless stated otherwise) --- ### 2) Best average score You are given a list of score records. Each record contains a `name` (string) and a `score` (integer). Return the **highest average score** among all names. - A person may appear multiple times; their average is the mean of their scores. - You may assume each person has at least one score. - Specify how you handle rounding (e.g., return a floating-point number, or return an exact rational/decimal). **Input:** `records = [(name1, score1), (name2, score2), ...]` **Output:** the maximum average across names **Constraints (typical):** - `1 <= len(records) <= 10^5` - `score` can be negative or positive (state assumption if you restrict it)