Problem A
Nine Knights — Problem Statistics

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Submissions	6931
Accepted submissions	2991
Submission ratio	43.15%
Authors	2845
Full solves [?]	2577
Full solve Ratio	90.58%

#	User	Runtime	Language	Date
1	Johan Pettersson	0.01 s	C#	2017-11-18 13:48:22
2	Ólafur Andri	0.01 s	C#	2018-02-01 21:58:53
3	Faisal Rahman	0.01 s	C#	2018-02-12 01:31:40
4	John Hollingsworth	0.02 s	C#	2017-11-06 00:45:15
5	Andreas Ljungberg	0.02 s	C#	2017-12-20 22:24:21
6	Kunwei Zhang	0.02 s	C#	2018-02-09 05:56:01
7	Dan Wolff	0.02 s	C#	2018-10-12 00:49:58
8	Alexander Grace an	0.02 s	C#	2018-12-30 16:28:54
9	Simon Grey	0.02 s	C#	2019-02-13 19:52:41
10	Daniel Fennhagen	0.02 s	C#	2019-04-11 11:56:26

#	User	Runtime	Language	Date
1	Ari Páll Agnarsson	0.01 s	Common Lisp	2021-01-22 06:29:19
2	David Cawthon	0.02 s	Common Lisp	2019-04-14 01:32:39
3	Hidden user	0.02 s	Common Lisp	2019-05-27 21:54:52

#	User	Runtime	Language	Date
1	Morten Clausen	0.03 s	F#	2022-03-11 16:59:18
2	Jacob Harris Cryer Kragh	0.03 s	F#	2022-10-10 10:20:02

#	User	Runtime	Language	Date
1	Dylan	0.00 s	Go	2025-10-07 23:47:44
2	Simon Fischer-Nielsen	0.02 s	Go	2023-02-23 22:26:39
3	Mitch Price	0.07 s	Go	2018-09-29 05:35:28
4	Norbert Voelker	0.08 s	Go	2021-05-05 13:00:08
5	Krzysztof Gibuła	0.08 s	Go	2021-05-07 21:51:22
6	Hidden user	0.08 s	Go	2021-06-21 15:53:54

#	User	Runtime	Language	Date
1	Olle Eriksson	0.00 s	Haskell	2017-11-12 19:17:53
2	Matthew Johnson	0.00 s	Haskell	2018-02-13 01:32:42
3	A Person	0.00 s	Haskell	2023-08-11 21:56:42
4	Steinar Simonnes	0.00 s	Haskell	2024-02-25 17:29:55
5	Evgeny Petrovsky	0.00 s	Haskell	2024-11-18 13:10:49
6	Brent Yorgey	0.01 s	Haskell	2017-11-04 22:34:13
7	Simen Endsjø	0.01 s	Haskell	2017-11-11 20:12:37
8	Håkon Flatval	0.01 s	Haskell	2018-08-19 17:56:26
9	Rudi Svartveit	0.01 s	Haskell	2018-08-31 12:53:43
10	Hidden user	0.01 s	Haskell	2019-08-25 13:00:42

#	User	Runtime	Language	Date
1	Bala Krishna	0.04 s	Java	2024-08-07 19:12:45
2	Hidden user	0.04 s	Java	2024-09-03 22:25:39
3	Apostolos Draganis	0.04 s	Java	2024-09-10 18:28:19
4	Jonas	0.04 s	Java	2024-10-08 20:37:19
5	Benjamin Alcocer	0.04 s	Java	2024-10-28 15:55:39
6	Lum Yi Ren Johannsen	0.04 s	Java	2024-12-05 15:36:55
7	Ayush Rigal	0.04 s	Java	2025-01-04 22:48:56
8	Ragna María Sverrisdóttir	0.04 s	Java	2025-01-18 22:35:58
9	Ranjith M	0.04 s	Java	2025-02-04 02:31:11
10	Tony Chen	0.04 s	Java	2025-06-22 23:45:46

#	User	Runtime	Language	Date
1	Hidden user	0.04 s	JavaScript (Node.js)	2025-05-13 01:14:31
2	Gurpartap Singh Bhatti	0.05 s	JavaScript (Node.js)	2019-02-28 21:54:51
3	Hidden user	0.05 s	JavaScript (Node.js)	2019-03-28 14:27:53
4	Mahad Haider	0.08 s	JavaScript (Node.js)	2023-01-23 22:44:52
5	Peter Kedemo	0.41 s	JavaScript (Node.js)	2019-12-27 23:40:37
6	Ni Mz	0.42 s	JavaScript (Node.js)	2020-10-17 17:34:39
7	Chris Wong	0.42 s	JavaScript (Node.js)	2022-01-14 13:05:51
8	Jaan Jaerving	0.42 s	JavaScript (Node.js)	2022-01-16 18:40:16

#	User	Runtime	Language	Date
1	Bjørn Chr. Soltvedt	0.01 s	JavaScript (SpiderMonkey)	2017-11-04 21:31:31
2	Martin Jay	0.01 s	JavaScript (SpiderMonkey)	2017-11-07 21:52:08
3	Nicklas Utgaard	0.01 s	JavaScript (SpiderMonkey)	2017-12-29 19:10:51
4	Nguyễn Mạnh Phúc	0.02 s	JavaScript (SpiderMonkey)	2018-08-31 04:26:30
5	Bernard Perrin	0.02 s	JavaScript (SpiderMonkey)	2019-01-24 18:23:11
6	Peter Menyes	0.02 s	JavaScript (SpiderMonkey)	2021-09-17 15:18:19
7	Christian Pilegaard Cederquist	0.02 s	JavaScript (SpiderMonkey)	2023-01-24 23:05:56
8	Zach Tschetter	0.02 s	JavaScript (SpiderMonkey)	2023-05-22 03:49:34
9	Jimmy Gustafsson	0.02 s	JavaScript (SpiderMonkey)	2024-08-27 22:49:08
10	Andrea Bianchessi	0.03 s	JavaScript (SpiderMonkey)	2018-08-29 22:50:40

#	User	Runtime	Language	Date
1	Danny Robinson	0.55 s	Julia	2023-10-11 00:49:10
2	Timothy Gaede	0.57 s	Julia	2024-03-26 14:39:22

#	User	Runtime	Language	Date
1	Johnny Baloney	0.13 s	Kotlin	2021-12-31 01:12:48
2	Stefan Kennedy	0.17 s	Kotlin	2017-12-05 22:20:34
3	Nick Ivanov	0.17 s	Kotlin	2018-03-06 04:08:19
4	Ravisai Tiruvuri	0.18 s	Kotlin	2024-04-30 06:55:11
5	Adam Koprowski	0.19 s	Kotlin	2020-08-18 23:12:32
6	Neil Harmon	0.20 s	Kotlin	2019-04-26 14:54:12
7	Phường Lên	0.20 s	Kotlin	2019-12-30 06:40:58
8	Jacob Huebner	0.20 s	Kotlin	2020-04-19 06:43:54
9	Hidden user	0.20 s	Kotlin	2020-05-31 13:43:25
10	Chris Lemaire	0.20 s	Kotlin	2020-12-07 21:03:19

#	User	Runtime	Language	Date
1	Ingemar Ragnemalm	0.00 s	Pascal	2017-11-25 10:57:48

#	User	Runtime	Language	Date
1	Jeff Cashion	0.01 s	PHP	2018-04-27 16:26:56
2	Connor Billings	0.01 s	PHP	2020-07-20 23:11:33
3	Victor Santos	0.01 s	PHP	2024-04-22 03:49:18
4	Nathã William Sena Soares	0.01 s	PHP	2024-04-23 21:38:29

#	User	Runtime	Language	Date
1	Andriy Zyevakov	0.01 s	Prolog	2018-11-17 00:41:54
2	Hakan Kjellerstrand	0.02 s	Prolog	2023-03-11 09:13:11

#	User	Runtime	Language	Date
1	Alex Zhao	0.02 s	Python 2	2017-11-04 18:52:26
2	Chad Stolper	0.02 s	Python 2	2017-11-04 22:38:33
3	Ethan Arnold	0.02 s	Python 2	2017-11-06 18:48:12
4	Çağdaş Öztekin	0.02 s	Python 2	2017-11-06 19:53:24
5	Andrei Stoica	0.02 s	Python 2	2017-11-06 23:12:35
6	Eric Williamson	0.02 s	Python 2	2017-11-09 02:49:18
7	Hidden user	0.02 s	Python 2	2017-11-21 01:45:25
8	Alexandria Davis	0.02 s	Python 2	2017-11-30 04:10:26
9	Ryan Beck	0.02 s	Python 2	2017-11-30 23:45:22
10	Maksym Bendeberia	0.02 s	Python 2	2017-12-05 17:37:54

#	User	Runtime	Language	Date
1	Tiancong Zhao	0.02 s	Python 3	2017-11-05 23:35:23
2	Allen Anthes	0.02 s	Python 3	2017-11-06 00:42:06
3	David Ludwig	0.02 s	Python 3	2017-11-06 04:15:11
4	Aditya Durvasula	0.02 s	Python 3	2017-11-06 07:44:42
5	James Hamm	0.02 s	Python 3	2017-11-06 15:04:39
6	Alexei Fedotov	0.02 s	Python 3	2017-11-07 14:28:11
7	Dalton Cole	0.02 s	Python 3	2017-11-08 02:06:38
8	Ram Basnet	0.02 s	Python 3	2017-11-08 03:59:47
9	Joshua Osterhus	0.02 s	Python 3	2017-11-09 00:06:30
10	Cliodhna Harrison	0.02 s	Python 3	2017-11-09 15:44:08

#	User	Runtime	Language	Date
1	Hidden user	0.04 s	Ruby	2018-10-06 10:29:47
2	Savvas Alexandrou	0.04 s	Ruby	2019-01-06 16:49:26
3	Hidden user	0.04 s	Ruby	2019-05-03 17:40:18
4	Hidden user	0.04 s	Ruby	2019-05-03 23:02:19
5	Davi Guimarães Leite	0.05 s	Ruby	2019-05-03 23:02:47
6	Kok Dith	0.05 s	Ruby	2021-08-20 11:11:35
7	Thomas Feld	0.06 s	Ruby	2023-10-13 11:02:46

#	User	Length	Language	Date
1	Hidden user	604	C	2025-01-05 15:18:42
2	sicupu	619	C	2020-10-14 16:51:52
3	Danial Motamedi Mehr	670	C	2020-03-09 20:14:41
4	Þórður Agust	734	C	2019-01-16 17:15:45
5	pengin	735	C	2021-05-11 12:27:41
6	Abdullah Al Mamun	736	C	2018-10-12 16:00:38
7	Adam Evans	836	C	2017-11-07 02:13:49
8	Hidden user	838	C	2017-11-17 16:21:04
9	Doni Prasetyo	864	C	2024-11-20 04:17:13
10	randy	866	C	2020-12-30 14:54:28

#	User	Length	Language	Date
1	Göran Andersson	853	C#	2022-05-16 18:55:46
2	Muhammed Edip Okur	1005	C#	2019-11-01 14:18:15
3	Kunwei Zhang	1223	C#	2018-02-09 05:56:01
4	Hidden user	1398	C#	2023-01-27 05:33:39
5	Thomas Norris	1625	C#	2020-01-06 20:40:15
6	Ólafur Andri	1636	C#	2018-02-01 21:58:53
7	Simon Grey	1674	C#	2019-02-13 19:52:41
8	Julio Axel Montero Barrientos	1679	C#	2022-09-28 00:09:23
9	Daniel Juhl	1795	C#	2022-03-11 17:46:53
10	Ricardo H Guerrero Lara	1827	C#	2022-09-27 22:26:13

#	User	Length	Language	Date
1	Nguyen Tran Huu Duc	444	C++	2022-01-02 14:59:29
2	Shirui Chen	559	C++	2018-10-28 18:30:08
3	Matthew Joseph Schallenkamp	561	C++	2019-02-09 02:41:39
4	traxex	562	C++	2021-12-14 08:01:39
5	Antoni Guz	567	C++	2018-01-19 01:17:02
6	Elias Lolck	579	C++	2022-03-11 16:09:38
7	Daniel Bordeianu	579	C++	2024-11-08 16:07:33
8	Alin Popovici	592	C++	2022-03-30 19:07:51
9	黃浚瑜	599	C++	2022-02-06 03:07:27
10	Johan Wind	601	C++	2018-03-17 17:47:52

#	User	Length	Language	Date
1	Hidden user	1207	Common Lisp	2019-05-27 21:54:52
2	David Cawthon	1344	Common Lisp	2019-04-14 01:32:39
3	Ari Páll Agnarsson	2809	Common Lisp	2021-01-22 06:29:19

#	User	Length	Language	Date
1	Morten Clausen	854	F#	2022-03-11 16:59:18
2	Jacob Harris Cryer Kragh	1744	F#	2022-10-10 10:20:02

#	User	Length	Language	Date
1	Mitch Price	694	Go	2018-09-29 05:35:28
2	Hidden user	723	Go	2021-06-21 15:53:54
3	Krzysztof Gibuła	765	Go	2021-05-07 21:51:22
4	Dylan	1089	Go	2025-10-07 23:47:44
5	Norbert Voelker	1122	Go	2021-05-05 13:01:12
6	Simon Fischer-Nielsen	1404	Go	2023-02-23 22:26:39

#	User	Length	Language	Date
1	Matthew Johnson	627	Haskell	2018-02-13 01:32:42
2	Brent Yorgey	632	Haskell	2017-11-04 22:34:13
3	Hidden user	644	Haskell	2019-08-25 13:00:42
4	Olle Eriksson	820	Haskell	2017-11-12 19:17:53
5	Håkon Flatval	882	Haskell	2018-08-19 17:56:26
6	Rudi Svartveit	893	Haskell	2018-08-31 12:53:43
7	Steinar Simonnes	992	Haskell	2024-02-25 17:29:55
8	Sergio Martín Sempere	1052	Haskell	2020-09-27 20:45:14
9	Darren Chang	1226	Haskell	2021-06-26 18:03:15
10	Juan Miguel Vilar	1265	Haskell	2020-09-22 15:07:43

#	User	Length	Language	Date
1	Doug Goodman	738	Java	2018-03-05 21:05:27
2	Qritel Abdelilah	748	Java	2017-12-31 02:23:40
3	Ali Pervaiz	782	Java	2019-03-25 16:23:10
4	Brennan Cleland	875	Java	2023-05-12 21:57:02
5	masakinpo	903	Java	2018-03-22 07:02:55
6	Hidden user	903	Java	2018-04-30 06:15:54
7	Hidden user	923	Java	2018-04-12 02:50:22
8	Yeung Man Tsung	935	Java	2022-06-22 11:00:58
9	Joey Woodson	937	Java	2017-11-06 02:26:40
10	Einar Þór Ívarsson	939	Java	2020-01-13 12:32:29

#	User	Length	Language	Date
1	Peter Kedemo	1016	JavaScript (Node.js)	2019-12-27 23:40:37
2	Hidden user	1051	JavaScript (Node.js)	2025-05-13 01:14:31
3	Jaan Jaerving	1192	JavaScript (Node.js)	2022-01-16 18:40:16
4	Chris Wong	1437	JavaScript (Node.js)	2022-01-14 13:05:51
5	Ni Mz	1515	JavaScript (Node.js)	2020-10-17 17:34:39
6	Hidden user	1647	JavaScript (Node.js)	2019-03-28 14:27:53
7	Mahad Haider	1714	JavaScript (Node.js)	2023-01-23 22:44:52
8	Gurpartap Singh Bhatti	2215	JavaScript (Node.js)	2019-02-28 21:54:51

#	User	Length	Language	Date
1	Jimmy Gustafsson	422	JavaScript (SpiderMonkey)	2024-08-27 22:49:08
2	Nguyễn Mạnh Phúc	586	JavaScript (SpiderMonkey)	2018-08-31 04:26:30
3	Christian Pilegaard Cederquist	604	JavaScript (SpiderMonkey)	2023-01-24 23:05:56
4	Zach Tschetter	627	JavaScript (SpiderMonkey)	2023-05-22 03:49:34
5	Bjørn Chr. Soltvedt	668	JavaScript (SpiderMonkey)	2017-11-04 21:31:31
6	Bernard Perrin	690	JavaScript (SpiderMonkey)	2019-01-24 18:23:11
7	Peter Menyes	695	JavaScript (SpiderMonkey)	2021-09-17 15:18:19
8	Martin Jay	1101	JavaScript (SpiderMonkey)	2017-11-07 21:53:12
9	Andrea Bianchessi	1112	JavaScript (SpiderMonkey)	2018-08-29 22:50:40
10	Nicklas Utgaard	1189	JavaScript (SpiderMonkey)	2017-12-29 19:10:51

#	User	Length	Language	Date
1	Danny Robinson	245	Julia	2023-10-11 00:49:10
2	Timothy Gaede	797	Julia	2024-03-26 14:39:22

#	User	Length	Language	Date
1	Chris Lemaire	663	Kotlin	2020-12-07 21:03:19
2	Stefan Kennedy	720	Kotlin	2017-12-05 22:20:34
3	Einar Kjellback	825	Kotlin	2020-01-20 21:05:16
4	Phường Lên	919	Kotlin	2019-12-30 06:40:58
5	Jacob Huebner	956	Kotlin	2020-04-19 06:47:29
6	Johnny Baloney	1117	Kotlin	2021-12-31 00:49:44
7	Adam Koprowski	1208	Kotlin	2020-08-18 23:12:32
8	Hidden user	1625	Kotlin	2020-05-31 13:43:25
9	Troy Warmboe	1878	Kotlin	2020-02-14 00:38:52
10	Neil Harmon	1920	Kotlin	2019-04-26 14:54:12

#	User	Length	Language	Date
1	Ingemar Ragnemalm	1091	Pascal	2017-11-25 10:57:48

#	User	Length	Language	Date
1	Victor Santos	725	PHP	2024-04-22 03:50:53
2	Connor Billings	924	PHP	2020-07-20 23:11:33
3	Jeff Cashion	1260	PHP	2018-04-27 16:26:56
4	Nathã William Sena Soares	2370	PHP	2024-04-23 21:38:29

#	User	Length	Language	Date
1	Hakan Kjellerstrand	786	Prolog	2023-03-11 09:13:11
2	Andriy Zyevakov	1207	Prolog	2018-11-17 00:41:54

#	User	Length	Language	Date
1	Andreas Eisele	333	Python 2	2018-10-13 15:56:00
2	Thomas Feld	380	Python 2	2019-09-03 14:16:27
3	Lars Åström	426	Python 2	2019-10-10 09:18:42
4	Andreas Björklund	436	Python 2	2021-04-06 22:15:00
5	Lim Hong Hui Eugene	439	Python 2	2018-04-30 11:30:45
6	Haggai Liu	492	Python 2	2018-02-01 07:35:19
7	Jeff Robertson	516	Python 2	2017-11-10 21:50:17
8	Maksym Bendeberia	554	Python 2	2017-12-05 17:37:54
9	Fan Zhang	560	Python 2	2017-11-12 22:50:52
10	Eric Williamson	565	Python 2	2017-11-09 02:49:18

#	User	Length	Language	Date
1	Tobias Glimmerfors	110	Python 3	2025-07-06 19:25:45
2	Erik Adebahr	140	Python 3	2025-07-06 23:39:17
3	Vide Wallström	169	Python 3	2025-07-06 22:36:50
4	Michael Goldwasser	187	Python 3	2024-03-27 23:56:42
5	Ahmed Chamseddine	229	Python 3	2024-08-20 21:13:54
6	Guk Yi Siong	234	Python 3	2023-12-22 10:46:10
7	Vinh Buu Tang	236	Python 3	2024-08-20 02:30:05
8	ACMCSU	236	Python 3	2025-03-30 04:53:28
9	Collin Simpson	242	Python 3	2025-03-30 04:49:49
10	Vedran Čačić	283	Python 3	2019-01-21 23:27:11

#	User	Length	Language	Date
1	Thomas Feld	78	Ruby	2023-10-13 11:36:21
2	Hidden user	539	Ruby	2019-05-03 17:40:18
3	Kok Dith	611	Ruby	2021-08-20 11:11:35
4	Hidden user	702	Ruby	2018-10-06 10:29:47
5	Hidden user	1468	Ruby	2019-05-03 23:02:19
6	Davi Guimarães Leite	1468	Ruby	2019-05-03 23:02:47
7	Savvas Alexandrou	1828	Ruby	2019-01-06 16:49:26

#	User	Length	Language	Date
1	Bas Dirks	879	Rust	2022-01-04 13:41:52
2	Henry Jayakusuma	1031	Rust	2020-05-31 08:38:38
3	Vincent Lagerros	1094	Rust	2025-08-10 01:49:26
4	Polly Clémentine Nielsen Boutet-Livoff	1095	Rust	2022-03-11 17:39:57
5	David Rasch	1323	Rust	2021-11-02 18:18:29
6	Reis Faar	1423	Rust	2023-04-16 20:40:20
7	Alexander Skovsende	1503	Rust	2022-03-11 16:45:05
8	Valdimar Örn	1580	Rust	2023-01-16 12:19:45
9	Alice Ryhl	1629	Rust	2022-03-11 16:09:58
10	Isak Jägberg	1821	Rust	2019-08-20 17:48:35

Solution running time distribution