Featurebranch

Summary by Bito

• Fixes critical bugs in AirlineProblem.java, including error handling, loop logic, and method signatures.
• Fixes arithmetic operator misuse in BinaryConverter.java.
• Fixes constant initialization and array size increment in IntListVer2.java.
• Overall summary: Fixes several critical bugs across AirlineProblem.java, BinaryConverter.java, and IntListVer2.java, enhancing code stability and reliability.