Codility Challenge: Gamer's 2021

FillTheGaps

• Difficulty: Hard
• Given a string consisting of characters 'a', 'b' and/or '?', replace each '?' with 'a' or 'b' so that the longest fragment of the resulting string consisting of equal letters is as short as possible.
• https://app.codility.com/programmers/challenges/gamers_2021/
• https://app.codility.com/programmers/task/fill_the_gaps/

Versions

• Result
  • Good: Correctness 100%, Performance 100%.
  • OK: Correctness 100%, Performance <100%.
  • Fail: Correctness <100%, Performance <100%.
• File naming convention
  • Code A: Gamers2021A.java
  • etc

Gold Award

File	Complexity	Result	Report
A	O(N * log(N)) or O(N)	Good	N7PTWR

Other

File	Complexity	Result	Report
B	O(N * log(N)) or O(N)	Good	6WTXMU

• Solution provided by Codility is written in Python and using yield command which not available in Java. So no java version implemented as it can't be compared fairly.
• Both A, B and Codility solutions are same concepts.
• A although earn a Gold award, but actually contains a bug, which failed the following scenario:
  • input: 'aaaa?bbb?aaa?bbb?aaa?bbb?aaaa', expected 5 (the program returns 4)
• B is the bug fix version of A