What I learned from Educational Round 81

Revision en3, by Way_Above_your_level_lol, 2020-01-30 19:20:02

Time: 9:15pm IST

  • Solved A
  • No idea B
  • TLE C
  • Not Read D -- Upsolve : Idea for A was exactly on point. can reduce time taken from 5 minutes to 4.

Got confused while solving B. Should've just written down math formulas instead of weird diagrams.

Was on right track for C i.e. greedy approach. Should've thought more about reducing time using hashmap.

Didn't read D since was preoccupied.

--- New Things to learn:

  1. How to use lower_bound() Will read on C++ forums.

  2. Euler totient functions: formula is easy but will watch youtube video for proof.

EDIT1 : Found link for proof. Time stamp for crux : 2:47 Euler totient proof

EDIT2: Found link for lower_bound() Lower_bound reference

---- Pending :

Still need to solve D and understand logic. Read and try E

Cheers.

History

 
 
 
 
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  Rev. Lang. By When Δ Comment
en4 English Way_Above_your_level_lol 2020-02-01 19:16:46 46
en3 English Way_Above_your_level_lol 2020-01-30 19:20:02 133
en2 English Way_Above_your_level_lol 2020-01-30 18:58:10 172
en1 English Way_Above_your_level_lol 2020-01-30 18:49:04 679 Initial revision (published)