Longest String Without AAA or BBB

Problem Overview

• Build the longest string by concatenating given counts of "AA", "AB", and "BB" without forming "AAA" or "BBB".
• Input: integers AA, AB, BB in [0..10]; Output: any longest valid non-empty string.
• Real-world domain: constrained string construction/sequence building, typical in a coding interview.
• Multiple valid results allowed; return any longest one.
• From Zolando interviews; a classic interview question and string problem.