Problem A
Black Friday — Problem Statistics

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Submissions	13041
Accepted submissions	5144
Submission ratio	39.44%
Authors	4983
Full solves [?]	4431
Full solve Ratio	88.92%

#	User	Runtime	Language	Date
1	Joe Amenta	0.01 s	C#	2016-04-04 21:28:48
2	Hidden user	0.02 s	C#	2015-04-26 11:19:02
3	Bas te Kolste	0.02 s	C#	2015-06-19 15:35:11
4	Charlie Forsberg Hedberg	0.02 s	C#	2015-07-07 10:32:08
5	Mads Storm Hansen	0.02 s	C#	2015-07-12 23:46:40
6	Niklas Huss	0.02 s	C#	2015-08-14 21:49:06
7	Jack Roip	0.02 s	C#	2015-08-22 09:42:20
8	Jonas S	0.02 s	C#	2015-08-24 01:50:15
9	Jens Mossig	0.02 s	C#	2015-08-27 09:54:18
10	Vitou Phy	0.02 s	C#	2015-08-29 19:18:41

#	User	Runtime	Language	Date
1	Krzys Hejno	0.01 s	D	2025-03-25 03:33:07

#	User	Runtime	Language	Date
1	عيسى علي عبدالله احمد	0.01 s	Dart	2024-07-04 18:08:14
2	Abdullah Ali Hussein	0.01 s	Dart	2024-07-04 18:25:39

#	User	Runtime	Language	Date
1	Jacob Harris Cryer Kragh	0.04 s	F#	2022-10-31 17:33:20

#	User	Runtime	Language	Date
1	Krzysztof Gibuła	0.07 s	Go	2019-03-11 21:09:37
2	Marcin Dudek	0.08 s	Go	2016-02-26 21:16:22
3	Hussein Al Abry	0.08 s	Go	2017-03-01 00:01:43
4	Ashleigh Bunkofske	0.08 s	Go	2017-10-23 11:13:03
5	Ciarán Ó hAoláin	0.08 s	Go	2017-12-18 13:00:30
6	Mik Achu	0.08 s	Go	2019-10-14 17:09:19
7	Ainun Nazieb	0.08 s	Go	2020-09-30 05:52:34
8	Abdurrachman Habibi	0.08 s	Go	2020-11-16 00:14:58
9	Adam Engsig	0.08 s	Go	2021-04-14 16:12:31
10	Daniel Andersson	0.08 s	Go	2021-05-07 09:46:23

#	User	Runtime	Language	Date
1	Guangyi Zhou	0.04 s	Java	2025-02-08 15:42:36
2	Daniel Gutierrez Duarte	0.04 s	Java	2025-03-17 17:38:39
3	Jens Ståhl	0.05 s	Java	2015-04-26 11:09:33
4	Richard Nysäter	0.05 s	Java	2015-04-26 11:22:38
5	Robin Andersson	0.05 s	Java	2015-04-26 11:27:37
6	Samuel Zackrisson	0.05 s	Java	2015-04-26 11:35:39
7	Axel Lewenhaupt	0.05 s	Java	2015-04-27 12:54:48
8	Nathaniel Lahn	0.05 s	Java	2015-08-10 03:56:57
9	Jeremy Alvin Chandranata	0.05 s	Java	2015-09-10 10:11:10
10	Anthony Wijaya	0.05 s	Java	2015-09-10 14:44:08

#	User	Runtime	Language	Date
1	Mina Thamer	0.04 s	JavaScript (Node.js)	2024-07-04 18:25:06
2	Ahmed Sameen	0.04 s	JavaScript (Node.js)	2024-07-04 18:34:28
3	Gonçalo Novo	0.04 s	JavaScript (Node.js)	2025-07-24 20:16:44
4	Sander Hellesø	0.05 s	JavaScript (Node.js)	2019-04-14 09:27:17
5	Mohammed Falih	0.05 s	JavaScript (Node.js)	2024-07-04 17:53:51
6	مصطفى عصام عبد الجبار	0.05 s	JavaScript (Node.js)	2024-07-04 18:11:58
7	Radhwan Muntasser Alzerary	0.05 s	JavaScript (Node.js)	2024-07-04 18:17:24
8	yousef alkobary	0.05 s	JavaScript (Node.js)	2024-07-04 18:25:34
9	sabaa safaa	0.05 s	JavaScript (Node.js)	2024-07-04 18:27:11
10	Hussein D. Jasim	0.05 s	JavaScript (Node.js)	2024-07-04 18:32:46

#	User	Runtime	Language	Date
1	Peter Kedemo	0.01 s	JavaScript (SpiderMonkey)	2015-12-26 00:11:49
2	Bjørn Chr. Soltvedt	0.01 s	JavaScript (SpiderMonkey)	2016-02-20 12:19:54
3	Gabriel Lau	0.01 s	JavaScript (SpiderMonkey)	2016-04-04 21:51:52
4	Hà Minh Ngọc	0.01 s	JavaScript (SpiderMonkey)	2016-07-26 14:12:44
5	Hidden user	0.01 s	JavaScript (SpiderMonkey)	2016-08-02 04:47:16
6	Nah Yi Feng	0.01 s	JavaScript (SpiderMonkey)	2017-11-10 07:51:48
7	Dilawar Mahmood	0.01 s	JavaScript (SpiderMonkey)	2018-01-15 17:11:34
8	Zachary DeStefano	0.01 s	JavaScript (SpiderMonkey)	2018-01-24 02:52:51
9	Christian Pilegaard Cederquist	0.02 s	JavaScript (SpiderMonkey)	2023-02-23 12:20:49
10	Zach Tschetter	0.02 s	JavaScript (SpiderMonkey)	2023-05-22 23:09:16

#	User	Runtime	Language	Date
1	Hidden user	0.57 s	Julia	2025-03-02 08:20:32
2	Danny Robinson	0.68 s	Julia	2023-10-22 12:26:59
3	Timothy Gaede	0.71 s	Julia	2024-03-26 15:04:39

#	User	Runtime	Language	Date
1	Johnny Baloney	0.13 s	Kotlin	2022-02-14 21:33:41
2	James WIlliams	0.14 s	Kotlin	2020-12-29 09:39:40
3	Dayan Ruben Gonzalez	0.15 s	Kotlin	2020-09-28 20:21:53
4	Jacob Huebner	0.16 s	Kotlin	2020-02-27 08:44:59
5	Hidden user	0.17 s	Kotlin	2017-11-11 00:18:00
6	Jahid Hasan Imon	0.18 s	Kotlin	2020-06-11 12:14:16
7	Sarek Høverstad Skotåm	0.19 s	Kotlin	2020-10-10 00:30:59
8	Adam Koprowski	0.19 s	Kotlin	2020-11-12 21:55:18
9	Vivek Naik	0.19 s	Kotlin	2021-05-19 20:16:27
10	Yaqub Patel	0.19 s	Kotlin	2021-06-21 13:34:22

#	User	Runtime	Language	Date
1	Caleb Austin	0.00 s	Lua	2024-09-06 22:36:11

#	User	Runtime	Language	Date
1	Ayoub Meskour	0.00 s	Objective-C	2016-06-10 08:53:10

#	User	Runtime	Language	Date
1	Albert Leung	0.00 s	OCaml	2020-09-02 05:43:41

#	User	Runtime	Language	Date
1	Egor Shchetinin	0.00 s	Pascal	2018-02-12 18:55:09
2	Vova Podkorytov	0.00 s	Pascal	2018-02-12 18:55:45
3	David Connolly	0.00 s	Pascal	2021-11-02 19:21:16
4	Joseph Chau	0.00 s	Pascal	2024-02-02 22:43:57

#	User	Runtime	Language	Date
1	Susanne Ragnemalm	0.01 s	PHP	2018-04-10 13:31:55
2	Renate	0.01 s	PHP	2022-08-11 23:32:28
3	Abdalazeez Firas	0.01 s	PHP	2024-07-04 18:09:55

#	User	Runtime	Language	Date
1	Hadi Qovaizi	0.01 s	Prolog	2016-04-22 04:48:58

#	User	Runtime	Language	Date
1	Erik Odenman	0.02 s	Python 2	2015-04-26 11:06:55
2	Joakim Uddholm	0.02 s	Python 2	2015-04-26 11:09:46
3	Fredrika Agestam	0.02 s	Python 2	2015-04-26 11:27:07
4	Christofer Ohlsson	0.02 s	Python 2	2015-04-27 11:09:32
5	Hidden user	0.02 s	Python 2	2015-04-28 15:51:51
6	Akash Kumar Dhaka	0.02 s	Python 2	2015-05-04 18:36:35
7	Mikael Hedin	0.02 s	Python 2	2015-05-12 21:50:07
8	Hidden user	0.02 s	Python 2	2015-05-22 16:43:13
9	Bojan Roško	0.02 s	Python 2	2015-06-10 18:06:42
10	Snild Dolkow	0.02 s	Python 2	2015-09-13 13:10:04

#	User	Runtime	Language	Date
1	Hidden user	0.02 s	Python 3	2015-04-26 11:07:26
2	Alex Loiko	0.02 s	Python 3	2015-04-26 11:09:06
3	Nils Gustafsson	0.02 s	Python 3	2015-04-26 11:23:14
4	Mikael Hedin	0.02 s	Python 3	2015-05-12 14:17:00
5	Fredrika Agestam	0.02 s	Python 3	2015-05-14 19:43:46
6	Tristan van Leeuwen	0.02 s	Python 3	2015-05-26 20:48:33
7	James Elías Sigurðarson	0.02 s	Python 3	2015-05-30 22:45:58
8	Johannes Agestam	0.02 s	Python 3	2015-06-15 00:57:46
9	Martin Stensgård	0.02 s	Python 3	2015-07-25 04:32:18
10	Hidden user	0.02 s	Python 3	2015-08-19 18:04:48

#	User	Runtime	Language	Date
1	Casper Christensen	0.03 s	Ruby	2016-02-04 12:40:15
2	Gerry Hall	0.03 s	Ruby	2016-03-27 07:44:04
3	Lasse Berglund	0.03 s	Ruby	2016-04-15 12:03:10
4	Erik Rydbert	0.03 s	Ruby	2016-07-07 10:46:38
5	Reed Harris	0.03 s	Ruby	2018-03-26 20:12:36
6	Hidden user	0.04 s	Ruby	2019-03-04 12:34:19
7	Hadi Qovaizi	0.05 s	Ruby	2021-06-28 11:36:40
8	Thomas Feld	0.06 s	Ruby	2023-03-10 10:04:27
9	Marcus Nogueira	0.06 s	Ruby	2024-05-03 23:46:33
10	Clement Oh	0.07 s	Ruby	2024-03-16 11:06:26

#	User	Length	Language	Date
1	Tor Storruste	290	C	2015-10-03 14:32:49
2	Nagata Parama Aptana	332	C	2021-08-10 17:38:48
3	Jonas Höglund	362	C	2015-04-26 11:14:15
4	Hidden user	402	C	2018-02-15 19:26:45
5	Markus Videll	404	C	2015-04-26 11:21:33
6	Ravi Teja	415	C	2017-01-03 08:49:43
7	Raviteja Danakonda	415	C	2018-04-18 10:23:04
8	Marco Merlini	423	C	2017-10-08 05:50:04
9	Lawrence Li	424	C	2016-01-08 09:38:55
10	Hidden user	424	C	2017-09-06 20:47:31

#	User	Length	Language	Date
1	Klas af Geijerstam	409	C#	2018-04-10 09:43:57
2	Brian Scott	449	C#	2018-09-18 09:09:45
3	Håkan Sjöström	463	C#	2021-11-24 11:10:32
4	Michael Damsgaard	543	C#	2024-12-31 06:46:08
5	Marek Bina	570	C#	2019-02-15 12:47:15
6	Deci Bel	638	C#	2025-03-30 12:52:18
7	Nathan Andrews	685	C#	2024-09-06 22:15:00
8	Göran Andersson	686	C#	2022-05-20 00:04:57
9	Marius Løkketangen	707	C#	2019-10-14 15:38:58
10	Márton Krauter	756	C#	2023-07-18 12:52:20

#	User	Length	Language	Date
1	Brandon Zhang	214	C++	2022-06-20 06:47:06
2	Dhipta Raditya	273	C++	2016-02-04 02:24:48
3	Đậu Huy Minh	289	C++	2022-03-16 22:34:44
4	Anna Roczek	289	C++	2023-08-20 13:42:13
5	Markus Mathiasen	290	C++	2022-11-14 18:24:05
6	Thiên Tài Zero	301	C++	2016-11-24 13:35:21
7	Srinath Venigandla	303	C++	2015-11-24 06:02:55
8	William Gan	306	C++	2017-01-01 16:00:28
9	Emma Nimstad	309	C++	2015-04-26 21:02:57
10	Simuzer	310	C++	2025-10-10 18:55:09

#	User	Length	Language	Date
1	Krzys Hejno	873	D	2025-03-25 03:33:07

#	User	Length	Language	Date
1	Abdullah Ali Hussein	585	Dart	2024-07-04 18:25:39
2	عيسى علي عبدالله احمد	1092	Dart	2024-07-04 18:09:24

#	User	Length	Language	Date
1	Jacob Harris Cryer Kragh	836	F#	2022-10-31 17:33:20

#	User	Length	Language	Date
1	Hussein Al Abry	442	Go	2017-03-01 00:01:43
2	Kyle Weaver	501	Go	2017-12-01 22:34:02
3	Ciarán Ó hAoláin	553	Go	2017-12-18 13:00:30
4	Ainun Nazieb	572	Go	2020-09-30 05:52:34
5	Iker Lissarrague	605	Go	2022-03-30 05:37:05
6	Krzysztof Gibuła	613	Go	2019-03-11 21:09:37
7	Abdurrachman Habibi	674	Go	2020-11-16 00:14:58
8	Norbert Voelker	717	Go	2021-07-06 20:00:53
9	Marcin Dudek	766	Go	2016-02-26 21:16:22
10	Daniel Andersson	770	Go	2021-05-07 09:46:23

#	User	Length	Language	Date
1	BlackcapCoder	228	Haskell	2019-05-12 11:28:17
2	Shinji Koshida	367	Haskell	2025-04-13 12:53:23
3	Lukas Polacek	392	Haskell	2015-07-02 23:37:49
4	Aurélien Pepin	393	Haskell	2019-09-04 15:41:04
5	Stefan Kennedy	402	Haskell	2018-11-06 03:52:14
6	Johan Meier	409	Haskell	2016-12-05 11:58:18
7	Dario Vidas	416	Haskell	2015-04-27 14:47:59
8	Hannah Dougherty	418	Haskell	2019-05-05 21:27:56
9	Lars Tveito	428	Haskell	2015-06-30 05:54:42
10	Jørn Lode	488	Haskell	2021-10-11 17:37:37

#	User	Length	Language	Date
1	Doug Goodman	412	Java	2017-09-06 16:23:18
2	Max Shelopugin	438	Java	2017-09-25 04:39:41
3	Fumi Yoshikoshi	457	Java	2020-08-07 11:11:04
4	Ajai Nelson	464	Java	2022-02-13 21:10:30
5	Hidden user	470	Java	2016-09-15 06:08:09
6	Frank Ruskey	479	Java	2017-07-28 22:30:29
7	Mitch Price	480	Java	2016-09-08 01:15:38
8	Dong Lee	486	Java	2018-02-27 02:06:07
9	Rodi Hasan	498	Java	2015-06-28 18:58:54
10	Xuehui Chen	502	Java	2018-07-18 04:34:12

#	User	Length	Language	Date
1	Gonçalo Novo	507	JavaScript (Node.js)	2025-07-24 20:16:44
2	Christina Moir	606	JavaScript (Node.js)	2020-10-21 16:18:39
3	Sander Hellesø	633	JavaScript (Node.js)	2019-04-14 09:27:17
4	Hussein D. Jasim	839	JavaScript (Node.js)	2024-07-04 18:32:46
5	sabaa safaa	1007	JavaScript (Node.js)	2024-07-04 18:27:11
6	Mohammed Falih	1015	JavaScript (Node.js)	2024-07-04 17:53:51
7	Mina Thamer	1046	JavaScript (Node.js)	2024-07-04 18:21:51
8	Ahmed Sameen	1078	JavaScript (Node.js)	2024-07-04 18:34:28
9	مصطفى عصام عبد الجبار	1240	JavaScript (Node.js)	2024-07-04 18:11:58
10	yousef alkobary	1655	JavaScript (Node.js)	2024-07-04 18:25:34

#	User	Length	Language	Date
1	Jimmy Gustafsson	125	JavaScript (SpiderMonkey)	2024-08-26 21:48:55
2	Zachary DeStefano	235	JavaScript (SpiderMonkey)	2018-01-24 02:52:51
3	Peter Kedemo	254	JavaScript (SpiderMonkey)	2015-12-26 00:11:49
4	Davíð Helgason	338	JavaScript (SpiderMonkey)	2019-06-25 15:08:10
5	Hà Minh Ngọc	350	JavaScript (SpiderMonkey)	2016-07-26 14:12:44
6	Hidden user	350	JavaScript (SpiderMonkey)	2016-08-02 04:47:16
7	Gabriel Lau	381	JavaScript (SpiderMonkey)	2016-04-04 21:51:52
8	Zach Tschetter	402	JavaScript (SpiderMonkey)	2023-05-22 23:09:16
9	Christian Pilegaard Cederquist	438	JavaScript (SpiderMonkey)	2023-02-23 12:20:49
10	Bjørn Chr. Soltvedt	488	JavaScript (SpiderMonkey)	2016-02-20 12:19:54

#	User	Length	Language	Date
1	Danny Robinson	132	Julia	2023-10-22 12:26:59
2	Hidden user	401	Julia	2025-03-02 08:20:32
3	Timothy Gaede	822	Julia	2024-03-26 15:04:39

#	User	Length	Language	Date
1	Dmitry Shostak	350	Kotlin	2018-08-20 13:56:20
2	Sarek Høverstad Skotåm	365	Kotlin	2020-10-10 00:30:59
3	Chris Johnson	415	Kotlin	2023-11-27 23:43:49
4	Adam Koprowski	434	Kotlin	2020-11-12 21:55:18
5	Dayan Ruben Gonzalez	435	Kotlin	2020-09-28 20:21:53
6	Marianne Grov	513	Kotlin	2019-10-14 16:14:14
7	Jahid Hasan Imon	560	Kotlin	2020-06-11 12:14:16
8	Hidden user	570	Kotlin	2017-11-11 00:18:00
9	Lewis Johnson	581	Kotlin	2023-11-27 23:57:44
10	Adam Rankin	631	Kotlin	2023-05-12 03:20:38

#	User	Length	Language	Date
1	Caleb Austin	1029	Lua	2024-09-06 22:36:11

#	User	Length	Language	Date
1	Ayoub Meskour	445	Objective-C	2016-06-10 08:53:10

#	User	Length	Language	Date
1	Albert Leung	679	OCaml	2020-09-02 05:43:41

#	User	Length	Language	Date
1	Egor Shchetinin	390	Pascal	2018-02-12 18:55:09
2	Vova Podkorytov	423	Pascal	2018-02-12 18:55:45
3	Joseph Chau	550	Pascal	2024-02-02 22:43:57
4	David Connolly	1210	Pascal	2021-11-02 19:21:16

#	User	Length	Language	Date
1	Susanne Ragnemalm	479	PHP	2018-04-10 13:31:55
2	Renate	479	PHP	2022-08-11 23:32:28
3	Abdalazeez Firas	888	PHP	2024-07-04 18:09:55

#	User	Length	Language	Date
1	Hadi Qovaizi	9700	Prolog	2016-04-22 04:48:58

#	User	Length	Language	Date
1	Erik Odenman	156	Python 2	2015-04-26 11:06:55
2	Hidden user	177	Python 2	2015-04-28 15:51:51
3	Hidden user	182	Python 2	2018-12-15 11:31:30
4	Akash Kumar Dhaka	197	Python 2	2015-05-04 18:41:35
5	Cole Bite	197	Python 2	2017-05-10 20:02:57
6	Arne Tobias Malkenes Ødegaard	202	Python 2	2015-09-17 18:30:50
7	Neal Zane	206	Python 2	2015-12-05 03:16:35
8	Guan Yang Ze	206	Python 2	2019-08-20 11:05:53
9	Finian Bradwell	210	Python 2	2017-12-10 23:26:27
10	Arnar Bjarni Arnarson	215	Python 2	2015-10-11 15:08:58

#	User	Length	Language	Date
1	Clement Oh	86	Python 3	2023-07-20 19:52:40
2	Lukas Kerren	98	Python 3	2024-04-28 02:34:18
3	Ahmed Chamseddine	106	Python 3	2023-08-28 09:22:41
4	Charles Ancheta	111	Python 3	2023-03-24 09:14:38
5	Simon Baeckelant	114	Python 3	2024-12-02 06:01:23
6	David Worley	126	Python 3	2025-11-07 20:29:21
7	Thibault Raffaillac	128	Python 3	2024-08-02 20:21:13
8	이정섭	138	Python 3	2022-07-21 20:04:10
9	Jason Clarke	144	Python 3	2024-01-29 19:13:54
10	Elias Amha	147	Python 3	2019-11-14 05:11:35

#	User	Length	Language	Date
1	Thomas Feld	82	Ruby	2023-03-10 10:06:03
2	Clement Oh	118	Ruby	2024-03-16 11:06:26
3	Reed Harris	213	Ruby	2018-03-26 20:12:36
4	Hidden user	250	Ruby	2019-03-04 12:34:19
5	Lasse Berglund	266	Ruby	2016-04-15 12:03:10
6	Casper Christensen	272	Ruby	2016-02-04 12:40:15
7	Gerry Hall	311	Ruby	2016-03-27 07:44:04
8	Marcus Nogueira	340	Ruby	2024-05-03 23:46:33
9	Erik Rydbert	511	Ruby	2016-07-07 10:46:38
10	Hadi Qovaizi	786	Ruby	2021-06-28 11:36:40

#	User	Length	Language	Date
1	Artur Khuziakhmetov	334	Rust	2023-08-21 15:11:42
2	Vincent Lagerros	562	Rust	2025-01-26 15:33:55
3	Shivam Thakur	582	Rust	2019-06-27 23:10:29
4	Joe Blower	657	Rust	2025-06-21 19:07:17
5	David Kaméus	662	Rust	2021-11-26 13:59:59
6	David Rasch	698	Rust	2020-11-18 14:50:21
7	Bas Dirks	859	Rust	2022-01-08 21:04:45
8	August Lind	924	Rust	2025-12-17 21:13:48
9	Anmol Sharma	1006	Rust	2018-11-14 07:48:58
10	Eric Leijonmarck	1018	Rust	2021-06-30 11:46:17

Solution running time distribution