Codeforces Round 921 (Div. 1)

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ContestId
Name
Phase
Frozen
Duration (Seconds)
Relative Time
Start Time
1924 Codeforces Round 921 (Div. 1) FINISHED False 7200 30813263 Jan. 27, 2024, 2:45 p.m.

Problems

Solved$
Index
Name
Type
Tags
Community Tag
Rating
( 158 ) F Anti-Proxy Attendance PROGRAMMING constructive algorithms interactive ternary search

B"This is an interactive problem! Mr. 1048576 is one of those faculty who hates wasting his time in taking class attendance. Instead of taking attendance the old-fashioned way, he decided to try out something new today. There are n students in his class, having roll numbers 1 to n . He knows that exactly 1 student is absent today. In order to determine who is absent, he can ask some queries to the class. In each query, he can provide two integers l and r ( 1 <= q l <= q r <= q n ) and all students whose roll numbers are between l and r (inclusive) will raise their hands. He then counts them to determine if the roll number of the absent student lies between these values. Things seemed fine until his teaching assistant noticed something -- the students are dishonest! Some students whose roll numbers lie in the given range may not raise their hands, while some other students whose roll number does not lie in the given range may raise their hands. But the students don't want to raise much suspicion. So, only the following 4 cases are possible for a particular query (l,r) -- In the first two cases, the students are said to be answering honestly, while in the last two cases, the students are said to be answering dishonestly. The students can mutually decide upon their strategy, not known to Mr. 1048576. Also, the students do not want to raise any suspicion and at the same time, want to create a lot of confusion. So, their strategy always meets the following two conditions -- Mr. 1048576 is frustrated by this act of students. So, he is willing to mark at most 2 students as absent (though he knows that only one is). The attendance is said to be successful if the student who is actually absent is among those two. Also, due to limited class time, he can only ask up to lceil log_{1.116}{n} rceil-1 queries (weird numbers but okay). Help him complete a successful attendance. First read a line c"...

Tutorials

Codeforces Round 921 (Div. 1, Div. 2) Editorial

Submissions

Submission Id
Author(s)
Index
Submitted
Verdict
Language
Test Set
Tests Passed
Time taken (ms)
Memory Consumed (bytes)
Tags
Rating
243632906 Szoboszlai10 F Jan. 27, 2024, 4:05 p.m. OK GNU C++17 TESTS 125 405 2048000
243674865 Benq F Jan. 27, 2024, 7:53 p.m. OK GNU C++17 (64) TESTS 125 296 2969600
243696319 chappy1 F Jan. 28, 2024, 2:09 a.m. OK GNU C++17 (64) TESTS 125 327 2969600
243703529 orzdevinwang F Jan. 28, 2024, 3:56 a.m. OK GNU C++17 (64) TESTS 125 358 16076800
243703469 orzdevinwang F Jan. 28, 2024, 3:56 a.m. OK GNU C++17 (64) TESTS 125 358 16076800
243690721 MW10 F Jan. 27, 2024, 11:55 p.m. OK GNU C++20 (64) TESTS 125 404 2969600
243695703 your_submissions_ F Jan. 28, 2024, 1:59 a.m. OK GNU C++20 (64) TESTS 125 436 20992000
243667546 gamegame F Jan. 27, 2024, 6:57 p.m. OK GNU C++20 (64) TESTS 125 436 20992000
243664810 Vercingetorix F Jan. 27, 2024, 6:43 p.m. OK GNU C++20 (64) TESTS 125 904 5427200
243665311 ksun48 F Jan. 27, 2024, 6:46 p.m. OK GNU C++20 (64) TESTS 125 1419 6246400

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