Problem A
Backspace — Problem Statistics

Back to problem description

Submissions	1187
Accepted submissions	834
Submission ratio	70.26%
Authors	290
Full solves [?]	213
Full solve Ratio	73.45%

#	User	Score	Language	Date
1	Einar Indridason	100	C	2017-07-03 19:19:55
2	Bergur Snorrason	100	C	2017-11-14 18:23:25
3	Óliver Máni	100	C	2020-03-21 11:25:57
4	Dagur Benjamínsson	100	C	2022-03-04 13:57:19
5	Gudjon Bjarki	100	C	2024-01-12 12:22:32
6	Álfgrímur Davíð	100	C	2025-03-17 23:56:15
7	Malcolm Holloway	100	C	2025-05-06 01:12:08
8	Ragnar Björn Ingvarsson	60	C	2023-11-21 14:53:06

#	User	Score	Language	Date
1	Þorgeir Auðunn Karlsson	100	C#	2016-05-29 21:38:37
2	Ólafur Andri	100	C#	2017-03-06 02:14:47
3	Sveinn Óli Guðmundsson	100	C#	2023-01-15 02:05:15
4	Pied Piper	60	C#	2016-03-19 11:19:21
5	Bjarki Fannar Snorrason	60	C#	2017-02-22 15:59:15
6	Alexander Freyr	60	C#	2017-03-19 01:46:41
7	Viktor Máni Mönster	60	C#	2018-03-15 01:49:49
8	Jóel Snær Garcia	60	C#	2018-03-16 15:32:54
9	Mikael Máni Jónsson	60	C#	2018-03-16 17:36:42
10	Rúnar Vestmann	60	C#	2019-03-19 17:39:21

#	User	Score	Language	Date
1	Gudjon Bjarki	60	F#	2024-01-10 22:21:31

#	User	Score	Language	Date
1	Hidden user	100	Go	2021-10-23 22:09:02

#	User	Score	Language	Date
1	Gudjon Bjarki	60	Haskell	2024-01-10 19:48:50

#	User	Score	Language	Date
1	Gamithra Marga	100	Java	2016-04-13 15:13:55
2	Gísli Freyr Sæmundsson	100	Java	2017-10-06 19:22:36
3	Issam Baskati	100	Java	2017-11-12 15:12:08
4	Einar Þór Ívarsson	100	Java	2020-02-10 17:08:47
5	Hans-Christian Kjeldsen	100	Java	2020-12-19 23:22:06
6	Sigurbjörg Erla	100	Java	2024-02-12 01:13:39
7	Guðbjörg Viðja	100	Java	2024-02-13 17:18:52
8	Þórður Friðriksson	60	Java	2017-03-14 16:32:53
9	Davíð Phuong Xuan Nguyen	60	Java	2017-03-15 13:23:29
10	Sindri Unnsteinsson	60	Java	2017-03-15 16:26:55

#	User	Score	Language	Date
1	Róbert Kristian Freysson	100	JavaScript (Node.js)	2023-01-01 19:47:23
2	Andri Þór Ólafsson	100	JavaScript (Node.js)	2025-02-26 19:22:12

#	User	Score	Language	Date
1	Sveinbjörn Stefán Einarsson	100	JavaScript (SpiderMonkey)	2017-03-18 04:04:57
2	Hidden user	100	JavaScript (SpiderMonkey)	2023-02-21 17:51:28
3	Mateusz Kolacz	100	JavaScript (SpiderMonkey)	2024-01-09 20:19:28
4	Gamithra Marga	60	JavaScript (SpiderMonkey)	2016-03-20 23:48:45

#	User	Score	Language	Date
1	주안석	100	Pascal	2017-11-20 05:27:16

#	User	Score	Language	Date
1	Johannes Laxdal	60	PHP	2017-02-18 01:45:23

#	User	Score	Language	Date
1	Greg Hamerly	100	Python 2	2016-04-27 19:46:32
2	Atli Þór Sveinbjarnarson	100	Python 2	2016-07-25 10:38:25
3	Garðar Ingvarsson	100	Python 2	2017-01-05 20:47:56
4	Guðni Natan Gunnarsson	100	Python 2	2017-02-16 16:20:04
5	Hidden user	100	Python 2	2017-03-26 22:13:56
6	Sigurður Jens Albertsson	100	Python 2	2017-11-09 22:46:05
7	knútur þór	100	Python 2	2024-01-05 12:54:39
8	Kristmundur Agust	60	Python 2	2016-03-19 12:17:09
9	Bernhard Kartefla	60	Python 2	2016-09-14 20:01:23
10	Unnar Bachmann	60	Python 2	2017-02-20 00:16:52

#	User	Score	Language	Date
1	Þorvaldur Tumi Baldursson	100	Rust	2023-02-14 17:56:43
2	Sverrir Hákon Marteinsson	100	Rust	2023-08-22 06:56:35
3	Tryggvi Thor Bogason	100	Rust	2024-12-29 18:23:25
4	Þorsteinn Sævar Kristjánsson	100	Rust	2025-09-28 03:49:50
5	Theodór Leví Halldórsson	100	Rust	2025-10-01 11:32:58
6	Frey Gígja	100	Rust	2026-02-14 23:12:16

#	User	Runtime	Language	Date
1	Einar Indridason	0.01 s	C	2017-07-03 19:19:55
2	Bergur Snorrason	0.01 s	C	2017-11-14 18:23:25
3	Óliver Máni	0.01 s	C	2020-03-21 11:25:57
4	Dagur Benjamínsson	0.01 s	C	2022-03-04 13:57:19
5	Gudjon Bjarki	0.01 s	C	2024-01-12 12:22:32
6	Álfgrímur Davíð	0.01 s	C	2025-03-17 23:56:15
7	Malcolm Holloway	0.01 s	C	2025-05-06 01:12:08

#	User	Runtime	Language	Date
1	Þorgeir Auðunn Karlsson	0.07 s	C#	2016-05-29 21:42:18
2	Sveinn Óli Guðmundsson	0.07 s	C#	2023-01-15 02:05:15
3	Ólafur Andri	0.09 s	C#	2017-03-06 02:14:47

#	User	Runtime	Language	Date
1	Hrant Hovhannisyan	0.01 s	C++	2017-03-25 10:28:31
2	Noah Weninger	0.01 s	C++	2018-12-18 23:52:17
3	Garðar Ingvarsson	0.01 s	C++	2019-02-06 01:32:34
4	Sesar Hersisson	0.01 s	C++	2019-02-11 11:07:21
5	Ásmundur Óskar Ásmundsson	0.01 s	C++	2019-02-11 11:14:40
6	Sigurjon Ingi	0.01 s	C++	2019-03-14 23:04:50
7	Guðmundur Bjarki Sigurðsson	0.01 s	C++	2020-02-11 15:04:33
8	Árni Bjarnsteinsson	0.01 s	C++	2020-02-11 23:02:08
9	Bjarni Haukur Bjarnason	0.01 s	C++	2020-08-27 03:07:25
10	Muhammad Mamdouh	0.01 s	C++	2021-01-26 19:13:09

#	User	Runtime	Language	Date
1	Hidden user	0.02 s	Go	2021-10-23 22:10:16

#	User	Runtime	Language	Date
1	Einar Þór Ívarsson	0.29 s	Java	2020-09-14 16:31:43
2	Issam Baskati	0.31 s	Java	2017-11-12 15:12:08
3	Sigurbjörg Erla	0.37 s	Java	2024-02-12 01:13:39
4	Gamithra Marga	0.39 s	Java	2016-04-13 15:13:55
5	Hans-Christian Kjeldsen	0.40 s	Java	2020-12-19 23:22:06
6	Gísli Freyr Sæmundsson	0.41 s	Java	2017-10-06 19:22:36
7	Guðbjörg Viðja	0.87 s	Java	2024-02-13 17:21:11

#	User	Runtime	Language	Date
1	Róbert Kristian Freysson	0.18 s	JavaScript (Node.js)	2023-01-01 19:47:23
2	Andri Þór Ólafsson	0.18 s	JavaScript (Node.js)	2025-02-26 19:22:12

#	User	Runtime	Language	Date
1	Mateusz Kolacz	0.07 s	JavaScript (SpiderMonkey)	2025-03-02 22:24:23
2	Hidden user	0.10 s	JavaScript (SpiderMonkey)	2023-02-21 17:51:28
3	Sveinbjörn Stefán Einarsson	0.68 s	JavaScript (SpiderMonkey)	2017-03-18 04:04:57

#	User	Runtime	Language	Date
1	주안석	0.02 s	Pascal	2017-11-20 05:27:16

#	User	Runtime	Language	Date
1	Sigurður Jens Albertsson	0.18 s	Python 2	2018-01-11 23:42:15
2	knútur þór	0.19 s	Python 2	2024-01-05 12:54:39
3	Hidden user	0.20 s	Python 2	2017-03-26 23:04:20
4	Guðni Natan Gunnarsson	0.22 s	Python 2	2017-02-16 16:20:04
5	Greg Hamerly	0.23 s	Python 2	2016-04-27 19:46:32
6	Garðar Ingvarsson	0.24 s	Python 2	2017-01-05 20:47:56
7	Atli Þór Sveinbjarnarson	0.25 s	Python 2	2016-07-25 10:38:25

#	User	Runtime	Language	Date
1	Þór Breki Davíðsson	0.15 s	Python 3	2018-03-15 19:57:49
2	Unnar Freyr Erlendsson	0.16 s	Python 3	2016-04-30 23:23:05
3	Guðmundur Brimir Björnsson	0.16 s	Python 3	2021-02-10 21:18:28
4	Issam Baskati	0.17 s	Python 3	2016-11-15 12:46:31
5	Viktor Máni Mönster	0.17 s	Python 3	2020-05-18 15:39:23
6	Arnar Bjarni Arnarson	0.17 s	Python 3	2021-04-29 18:34:28
7	Hidden user	0.17 s	Python 3	2023-02-11 15:44:47
8	Friðbjörn Árni Sigurðarson	0.17 s	Python 3	2023-03-05 18:59:08
9	alexandra nótt	0.17 s	Python 3	2023-03-10 21:41:08
10	Bjarki Ágúst Guðmundsson	0.17 s	Python 3	2025-01-12 05:47:41

#	User	Runtime	Language	Date
1	Þorvaldur Tumi Baldursson	0.01 s	Rust	2023-02-14 17:56:43
2	Sverrir Hákon Marteinsson	0.01 s	Rust	2023-08-22 07:03:48
3	Tryggvi Thor Bogason	0.01 s	Rust	2024-12-29 18:23:25
4	Þorsteinn Sævar Kristjánsson	0.01 s	Rust	2025-09-28 03:49:50
5	Theodór Leví Halldórsson	0.01 s	Rust	2025-10-01 11:32:58
6	Frey Gígja	0.01 s	Rust	2026-02-14 23:12:16

#	User	Length	Language	Date
1	Bergur Snorrason	265	C	2017-11-14 18:23:25
2	Malcolm Holloway	268	C	2025-05-06 01:16:29
3	Óliver Máni	314	C	2024-03-08 18:16:16
4	Dagur Benjamínsson	342	C	2022-03-04 13:57:19
5	Einar Indridason	447	C	2017-07-03 19:19:55
6	Gudjon Bjarki	452	C	2025-03-01 17:54:10
7	Álfgrímur Davíð	650	C	2025-03-17 23:56:15

#	User	Length	Language	Date
1	Þorgeir Auðunn Karlsson	515	C#	2016-05-29 21:38:37
2	Ólafur Andri	761	C#	2017-03-06 02:14:47
3	Sveinn Óli Guðmundsson	1024	C#	2023-01-15 02:05:15

#	User	Length	Language	Date
1	Noah Weninger	214	C++	2018-12-18 23:55:27
2	Bernhard Kartefla	226	C++	2017-02-15 17:52:18
3	Gunnar Bjorn	235	C++	2023-02-15 20:16:30
4	Bjarni Haukur Bjarnason	255	C++	2020-08-27 03:04:04
5	Vladyslav Reznikov	271	C++	2022-05-28 15:47:03
6	Kjartan Óli Ágústsson	288	C++	2024-02-15 23:29:30
7	Samúel Arnar Hafsteinsson	292	C++	2025-03-30 16:19:57
8	Friðrik Njálsson	295	C++	2017-02-16 16:00:42
9	Gunnsteinn Þór Ólason	301	C++	2024-06-05 19:44:46
10	Naod Philemon	303	C++	2021-11-02 02:04:33

#	User	Length	Language	Date
1	Hidden user	1336	Go	2021-10-23 22:09:02

#	User	Length	Language	Date
1	Einar Þór Ívarsson	414	Java	2020-02-10 17:08:47
2	Gísli Freyr Sæmundsson	560	Java	2017-10-06 19:22:36
3	Sigurbjörg Erla	619	Java	2024-02-14 15:02:12
4	Hans-Christian Kjeldsen	650	Java	2020-12-19 23:22:06
5	Gamithra Marga	739	Java	2016-04-13 15:13:55
6	Guðbjörg Viðja	972	Java	2024-02-14 15:47:20
7	Issam Baskati	3181	Java	2017-11-12 15:12:08

#	User	Length	Language	Date
1	Róbert Kristian Freysson	457	JavaScript (Node.js)	2023-01-01 19:47:23
2	Andri Þór Ólafsson	493	JavaScript (Node.js)	2025-02-26 19:22:12

#	User	Length	Language	Date
1	Mateusz Kolacz	122	JavaScript (SpiderMonkey)	2025-03-02 22:24:23
2	Hidden user	159	JavaScript (SpiderMonkey)	2023-02-21 17:51:28
3	Sveinbjörn Stefán Einarsson	261	JavaScript (SpiderMonkey)	2017-03-18 04:04:57

#	User	Length	Language	Date
1	주안석	305	Pascal	2017-11-20 05:27:16

#	User	Length	Language	Date
1	Sigurður Jens Albertsson	179	Python 2	2018-01-11 23:42:15
2	Garðar Ingvarsson	186	Python 2	2017-01-05 20:47:56
3	Greg Hamerly	204	Python 2	2016-04-27 19:46:32
4	Hidden user	204	Python 2	2017-03-26 23:04:20
5	Guðni Natan Gunnarsson	235	Python 2	2017-02-16 16:20:04
6	Atli Þór Sveinbjarnarson	247	Python 2	2016-07-25 10:38:25
7	knútur þór	402	Python 2	2024-01-05 12:54:39

#	User	Length	Language	Date
1	Fredrik Niemelä	75	Python 3	2025-08-24 04:51:02
2	Björn Thor Stefánsson	76	Python 3	2024-02-16 17:59:07
3	Hallgrímur Haraldsson	81	Python 3	2023-02-15 12:44:44
4	Sverrir Hákon Marteinsson	84	Python 3	2023-08-09 02:12:15
5	Tristan Pétur Andersen Njálsson	115	Python 3	2021-02-09 17:02:26
6	Hidden user	117	Python 3	2026-02-10 23:18:52
7	Garðar Ingvarsson	118	Python 3	2019-01-07 14:57:13
8	Svana Björg Birgisdóttir	119	Python 3	2024-02-12 22:30:23
9	James Elías Sigurðarson	120	Python 3	2016-03-19 15:19:21
10	Valdimar John Parks	120	Python 3	2017-03-16 14:35:17

#	User	Length	Language	Date
1	Frey Gígja	358	Rust	2026-02-14 23:12:16
2	Þorsteinn Sævar Kristjánsson	372	Rust	2025-09-28 03:49:50
3	Theodór Leví Halldórsson	419	Rust	2025-10-01 11:32:58
4	Sverrir Hákon Marteinsson	421	Rust	2023-08-22 07:19:47
5	Tryggvi Thor Bogason	471	Rust	2024-12-29 18:33:16
6	Þorvaldur Tumi Baldursson	979	Rust	2023-07-10 14:19:11

Solution running time distribution