Understanding the capabilities and limitations of programming-oriented AI models is crucial. This paper evaluates the programming proficiency of GPT-3.5 and GPT-4 using Codewars coding problems of varying difficulty. The experiments reveal a distinct boundary at the 3kyu level, beyond which these models struggle. This led to proposing a complexity measure that includes problem difficulty and solution time. The research emphasizes the need for validation and creative thinking in AI models to better emulate human problem-solving. Future work aims to refine the complexity measure, enhance AI capabilities, and develop an objective programming problem difficulty measure. These insights are valuable for advancing AI programming and problem-solving abilities.