### abistrigova's blog

By abistrigova, history, 8 years ago,

How to solve K, C?

• +25

 » 8 years ago, # |   0 How to solve L?
•  » » 8 years ago, # ^ | ← Rev. 5 →   +8 First, check what if a = 0 or c = 0then if b is max and it's equal to F_{i+1} then D = b2 - 4ac = (Fi + fi - 1)2 - 4fifi - 1 = (fi - fi - 1)2 that is usually greater than 0, and zero if fi = fi - 1 i.e i = 2otherwise D < 0 and there's no solutions.fi2 - 4fi + 2fi + 1 < fi2 - 4fifi < 0fi2 - 4fi + 1fi - 1 = fi2 - fi + 1fi - 1 - 3fi + 1fi - 1 =  ± 1 - 3fi + 1fi - 1 ≤  - 2 < 0
 » 8 years ago, # |   0 Which C? It is better if organizers do not name different tasks with same letters.
 » 8 years ago, # |   0 G. How did you solved it? After splitting to sentences I tried to grep them with regex, but got TLE 29 (ideone). Then tried use hashes, but failed on TC#3 (give a hint). Can't overcome it in two ways: 1) take each sentence as a hash key, which value is a hash of lowercased words;(ideone) 2) each word from sentences is lowercased and is a hash key, which value is an array of indices of an array of sentences.(ideone). Later improved(maybe) regex solution with lookaheads, but there is no Upsolving for Div.2 :/ to test if it pass time limits (ideone).