Fixed Problem Difficulty, Author Rating, and Solver Rating Calculations

For a very long time, problem difficulty calculation was disabled on Toph. It and a few other things were disabled to make it easier to transition from Toph’s old database code to the current one.

This is a companion discussion topic for the original entry at

I wonder how Toph calculates problem difficulty.

Modified ELO. Roughly speaking: If a problem takes more submissions in average to be solved, it is considered to be harder.

Each problem is then assigned a score between -1.0 and 1.0 (easy to hard).

I can guess why Copycat was once judged as a very hard problem. :rofl:

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Problems that are mostly attempted by beginners is a challenge in this method of estimating difficulty.

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Oh anyways,

The like in this post seems to be your 50th like given to me.