How much of the article did you read? They were looking for a senior, with more than twice the experience the poster has. Being able to pump out algos is only part of the job.

While there a solution is clever, it’s not terribly maintainable and likely didn’t fit the bill.

Beyond that, things like soft skills matter for senior roles. The author can write, there’s no denying that, but we don’t know how well they can explain the why of their solution. It’s very likely the interviewers wanted more traditional functions that were unit-testable.