Educational Codeforces Round 81 Postmortem

What went well

• If I had actually solved 4 problems, I would have gained over 100 elo…
• I solved D, which was a number theory problem. (Nick missed this problem; muahahaha)

What went wrong

• My impure thoughts on problem B died on system test #11. Since I passed all 10 pretests, I didn't think to revisit my solution and verify with fast-slow testing.
• I took a long time to recognize the totient function. My first reaction was "some inclusion-exclusion counting" upon realizing a pattern from my scratch work. Then I needed two tries to code a fast (sqrt N) totient function.

 Where I got lucky

• Everyone else died on B. Turns out it is rated 1800.