VK Cup 2019-2020 - Elimination Round (Engine)

Solutions are presented as using the least memory and the fastest execution time. It also takes the top 10 most recent solutions from each language. If you want to limit to a specific index, click the "Solved" button and go to that problem.

ContestId
Name
Phase
Frozen
Duration (Seconds)
Relative Time
Start Time
1310 VK Cup 2019-2020 - Elimination Round (Engine) FINISHED False 9000 149349299 Feb. 23, 2020, 4:05 p.m.

Problems

Solved$
Index
Name
Type
Tags
Community Tag
Rating
( 77 ) F Bad Cryptography PROGRAMMING math number theory 3300

B"In modern cryptography much is tied to the algorithmic complexity of solving several problems. One of such problems is a discrete logarithm problem. It is formulated as follows: It is most likely that modern mankind cannot solve the problem of discrete logarithm for a sufficiently large field size. For example, for a field of residues modulo prime number, primes of 1024 or 2048 bits are considered to be safe. However, calculations with such large numbers can place a significant load on servers that perform cryptographic operations. For this reason, instead of a simple module residue field, more complex fields are often used. For such field no fast algorithms that use a field structure are known, smaller fields can be used and operations can be properly optimized. Developer Nikolai does not trust the generally accepted methods, so he wants to invent his own. Recently, he read about a very strange field -- nimbers, and thinks it's a great fit for the purpose. The field of nimbers is defined on a set of integers from 0 to 2^{2^k} - 1 for some positive integer k . Bitwise exclusive or ( oplus ) operation is used as addition. One of ways to define multiplication operation ( odot ) is following properties: For example: Formally, this algorithm can be described by following pseudo-code. It can be shown, that this operations really forms a field. Moreover, than can make sense as game theory operations, but that's not related to problem much. With the help of appropriate caching and grouping of operations, it is possible to calculate the product quickly enough, which is important to improve speed of the cryptoalgorithm. More formal definitions as well as additional properties can be clarified in the wikipedia article at link. The authors of the task hope that the properties listed in the statement should be enough for the solution. Powering for such muliplication is defined in same way, formally a^{ odot k} = underbrace{a odot a "...

Tutorials

VK Cup 2019-2020 - Elimination Round (Engine) and Codeforces Round #623

Submissions

Submission Id
Author(s)
Index
Submitted
Verdict
Language
Test Set
Tests Passed
Time taken (ms)
Memory Consumed (bytes)
Tags
Rating
71915774 little_misfortune F Feb. 26, 2020, 1:14 p.m. OK GNU C++17 TESTS 32 468 33996800 3300
71868117 ftiasch F Feb. 25, 2020, 3:24 p.m. OK GNU C++17 TESTS 32 888 1433600 3300
71944474 the_art_of_war F Feb. 27, 2020, 12:36 a.m. OK GNU C++17 TESTS 32 1122 409600 3300
71944603 the_art_of_war F Feb. 27, 2020, 12:42 a.m. OK GNU C++17 TESTS 32 1138 409600 3300
71944581 the_art_of_war F Feb. 27, 2020, 12:41 a.m. OK GNU C++17 TESTS 32 1185 409600 3300
71944586 the_art_of_war F Feb. 27, 2020, 12:41 a.m. OK GNU C++17 TESTS 32 1201 409600 3300
71944537 the_art_of_war F Feb. 27, 2020, 12:39 a.m. OK GNU C++17 TESTS 32 1201 409600 3300
71730779 Petr F Feb. 23, 2020, 7:59 p.m. OK GNU C++17 TESTS 32 1575 1126400 3300
71944565 the_art_of_war F Feb. 27, 2020, 12:40 a.m. OK GNU C++17 TESTS 32 1591 4505600 3300
71727149 tourist F Feb. 23, 2020, 6:33 p.m. OK GNU C++17 TESTS 32 2106 4300800 3300
71723497 eatmore F Feb. 23, 2020, 6:09 p.m. OK Java 11 TESTS 32 1840 33484800 3300

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