Codeforces Round 1082 (Div. 1)

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ContestId
Name
Phase
Frozen
Duration (Seconds)
Relative Time
Start Time
2201 Codeforces Round 1082 (Div. 1) FINISHED False 9000 4548323 Feb. 23, 2026, 2:35 p.m.

Problems

Solved
Index
Name
Type
Tags
Community Tag
Rating
( 4809 ) B Recollect Numbers PROGRAMMING constructive algorithms

There are (2n) cards with numbers (1,1,2,2,\ldots,n,n) written on them. In other words, for all (j=1,2,\ldots,n), there are exactly (2) cards with the number (j). Each card only has one number written on its front. You will play a card flipping game. Initially, all (2n) cards are placed on their back (the side without numbers). In each turn, you flip exactly two cards. If the two cards have the same number, you discard the two cards. Otherwise, you flip them back to their original position. You win when all (2n) cards are discarded. Note that you do not have to flip the two cards simultaneously, so you can decide on your choice of the second card after seeing the number on the first one. Consider the following "greedy" algorithm to play the game. Initially, the (2n) cards are placed in a row arbitrarily. Then your strategy on each turn is as follows: If there are two cards that you have flipped previously and have the same number , flip those two cards. Otherwise, flip the first card (^\text{*}) that you have never flipped so far as the first one. Let's say this card has the number (x). Afterwards, if there is another card that you have flipped previously and has the number (x) , flip that card. Otherwise, flip the first card (^{\text{∗}}) that you have never flipped so far ( including in this turn ) as the second one. Afterwards, if there is another card that you have flipped previously and has the number (x) , flip that card. Otherwise, flip the first card (^{\text{∗}}) that you have never flipped so far ( including in this turn ) as the second one. It can be shown that the algorithm's strategy is uniquely determined on every turn. You must solve the following problem regarding the algorithm stated above. Given (n) and (k), please find an orientation of the (2n) cards for which the algorithm above takes exactly (k) turns to win the game. Additionally, if such an orientation does not

Tutorials

Codeforces Round 1082 (Div. 1, Div. 2) Complete Editorial

Submissions

Submission Id
Author(s)
Index
Submitted
Verdict
Language
Test Set
Tests Passed
Time taken (ms)
Memory Consumed (bytes)
Tags
Rating
364076578 -firefly- B Feb. 23, 2026, 3:47 p.m. OK C# 13 TESTS 19 93 41881600
364070403 sjtu-wya2007 B Feb. 23, 2026, 3:33 p.m. OK C++17 (GCC 7-32) TESTS 19 46 6656000
364075670 Taechka B Feb. 23, 2026, 3:44 p.m. OK C++17 (GCC 7-32) TESTS 19 78 0
364064264 Because_I_Love_You B Feb. 23, 2026, 3:21 p.m. OK C++17 (GCC 7-32) TESTS 19 78 0
364054375 Kasane_Teto B Feb. 23, 2026, 3:05 p.m. OK C++17 (GCC 7-32) TESTS 19 78 102400
364067727 timg8710 B Feb. 23, 2026, 3:28 p.m. OK C++17 (GCC 7-32) TESTS 19 78 2355200
364082577 orzchenhaoxuan B Feb. 23, 2026, 4:01 p.m. OK C++17 (GCC 7-32) TESTS 19 78 2457600
364051604 Potassium B Feb. 23, 2026, 3:01 p.m. OK C++17 (GCC 7-32) TESTS 19 78 2560000
364153702 dkedu B Feb. 24, 2026, 5:44 a.m. OK C++17 (GCC 7-32) TESTS 19 93 0
364076104 lwm7708 B Feb. 23, 2026, 3:46 p.m. OK C++17 (GCC 7-32) TESTS 19 93 0
364063278 lee_min_hoii B Feb. 23, 2026, 3:20 p.m. OK C++17 (GCC 7-32) TESTS 19 93 0
364082727 Jensen123 B Feb. 23, 2026, 4:02 p.m. OK C++20 (GCC 13-64) TESTS 19 46 102400
364063253 ahsoltan B Feb. 23, 2026, 3:20 p.m. OK C++20 (GCC 13-64) TESTS 19 46 102400
364062359 ya_ssh B Feb. 23, 2026, 3:18 p.m. OK C++20 (GCC 13-64) TESTS 19 46 102400
364062980 ukbwyx B Feb. 23, 2026, 3:19 p.m. OK C++20 (GCC 13-64) TESTS 19 46 3481600
364049378 Utena B Feb. 23, 2026, 2:58 p.m. OK C++20 (GCC 13-64) TESTS 19 46 4915200
364051010 Zheng_iii B Feb. 23, 2026, 3 p.m. OK C++20 (GCC 13-64) TESTS 19 46 18124800
364144670 creesh_krx B Feb. 24, 2026, 3:08 a.m. OK C++20 (GCC 13-64) TESTS 19 62 0
364082565 houren B Feb. 23, 2026, 4:01 p.m. OK C++20 (GCC 13-64) TESTS 19 62 0
364081126 Xerxes B Feb. 23, 2026, 3:57 p.m. OK C++20 (GCC 13-64) TESTS 19 62 0
364067994 mewmewmew B Feb. 23, 2026, 3:29 p.m. OK C++20 (GCC 13-64) TESTS 19 62 0
364064251 askd B Feb. 23, 2026, 3:21 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 46 0
364052042 re-wa-tl-ok B Feb. 23, 2026, 3:01 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 46 102400
364046803 tickcross.y B Feb. 23, 2026, 2:54 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 46 2150400
364077572 csp1025 B Feb. 23, 2026, 3:49 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 46 3686400
364055361 Gheal B Feb. 23, 2026, 3:07 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 46 4096000
364140055 Kevin911 B Feb. 24, 2026, 1:26 a.m. OK C++23 (GCC 14-64, msys2) TESTS 19 46 4915200
364135285 Dymeztky B Feb. 23, 2026, 11:16 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 62 0
364125626 Sora213 B Feb. 23, 2026, 8:56 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 62 0
364073892 Anemone_ B Feb. 23, 2026, 3:41 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 62 0
364063457 Boboge B Feb. 23, 2026, 3:20 p.m. OK C++23 (GCC 14-64, msys2) TESTS 19 62 0
364079639 Gassa B Feb. 23, 2026, 3:54 p.m. OK D TESTS 19 343 10547200
364097311 pengin_2000 B Feb. 23, 2026, 4:45 p.m. OK GNU C11 TESTS 19 140 2457600
364078381 omaltsev B Feb. 23, 2026, 3:51 p.m. OK Haskell TESTS 19 234 1024000
364134030 GaleStarr B Feb. 23, 2026, 10:49 p.m. OK Java 21 TESTS 19 421 61337600
364122016 daniel.glabai B Feb. 23, 2026, 8:16 p.m. OK Java 21 TESTS 19 562 1126400
364058519 NeelmaniPandey09 B Feb. 23, 2026, 3:12 p.m. OK Java 8 TESTS 19 312 35635200
364057016 Tlatoani B Feb. 23, 2026, 3:09 p.m. OK Kotlin 2.2 TESTS 19 484 38809600
364050291 bcollet B Feb. 23, 2026, 2:59 p.m. OK PyPy 2 TESTS 19 156 24166400
364067031 Emikooh B Feb. 23, 2026, 3:27 p.m. OK PyPy 3-64 TESTS 19 125 22630400
364080453 hitman_py B Feb. 23, 2026, 3:56 p.m. OK PyPy 3-64 TESTS 19 125 37888000
364059423 Nikrien B Feb. 23, 2026, 3:13 p.m. OK PyPy 3-64 TESTS 19 140 24473600
364070080 hugoback01 B Feb. 23, 2026, 3:33 p.m. OK PyPy 3-64 TESTS 19 140 24883200
364148468 pt50hgm B Feb. 24, 2026, 4:16 a.m. OK PyPy 3-64 TESTS 19 156 19046400
364045512 literalchild B Feb. 23, 2026, 2:52 p.m. OK PyPy 3-64 TESTS 19 156 36249600
364071048 shade34 B Feb. 23, 2026, 3:35 p.m. OK PyPy 3-64 TESTS 19 171 19660800
364085270 yupooh B Feb. 23, 2026, 4:08 p.m. OK PyPy 3-64 TESTS 19 171 36147200
364060965 Jank B Feb. 23, 2026, 3:16 p.m. OK PyPy 3-64 TESTS 19 171 36147200
364057247 twosquares B Feb. 23, 2026, 3:10 p.m. OK PyPy 3-64 TESTS 19 171 36147200
364052345 Jimanbanashi B Feb. 23, 2026, 3:02 p.m. OK Python 2 TESTS 19 234 35635200
364055541 Solalyth B Feb. 23, 2026, 3:07 p.m. OK Rust 2021 TESTS 19 62 13004800
364070444 Mon_ster B Feb. 23, 2026, 3:34 p.m. OK Rust 2024 TESTS 19 78 12595200
364070962 mertyilmaz B Feb. 23, 2026, 3:35 p.m. OK Rust 2024 TESTS 19 78 21401600
364056709 DanielAnker B Feb. 23, 2026, 3:09 p.m. OK Rust 2024 TESTS 19 93 24985600
364049733 Darknef B Feb. 23, 2026, 2:58 p.m. OK Rust 2024 TESTS 19 109 19865600

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