I was asked to implement a hands-on game coding on a laptop within a 3-hour timeframe. After finishing it, the HR mentioned that it would be submitted to the UK team, who would review it. This process may take up to one week.

Palindrome Game

A palindrome is a word, phrase, number, or other sequence of units that may be read the same way in either direction, with general allowances for adjustments to punctuation and word dividers.

e.g.

1. "Madam, I'm Adam!"
2. "Do geese see God?"
3. "A man, a plan, a canal - Panama!"

Implement a console-based palindrome game where the input follows a string and is optionally followed by the player's name.

Rules

1. If the player enters a valid palindrome, then increase the score by half the palindrome's length.
2. The game also lists the top 5 Hall-of-Fame players based on score ranks.
3. The game should register the player if not already registered.
4. If the server resets, then the player's score should be reset to zero.

Considerations

1. The game's state should be in-session memory and not be persisted to disk or database.
2. Design, Thread Safety, Concurrency & Readability aspects.
3. Write unit test cases.

Apart from this, there are also another set of technical questions - oops, coding (4) & SQL (1) - we need to answer by reasoning and implementation.