I went to ICPC's web pages, downloaded the first problem (problem A) and gave it to GPT-5, asking it for code to solve it (stating it was a problem from a recent competitive programming contest).
It thought for 7m 53s and gave as reply
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Sounds like a bug. Did you try it again (or with another leading-edge model) and get a similar result?
1. What was your prompt? 2. Why did you give it to GPT-5 instead of GPT-5 Thinking or GPT-5 Pro?