Largest Square Submatrix of all 1's

Find the largest square submatrix consisting entirely of 1s as fast as possible.

Input

A 10,000 x 10,000 matrix of uint8 values (0 or 1) on STDIN.

0, 1, 0, 1, 1
0, 1, 1, 1, 1
0, 0, 1, 0, 0
1, 0, 1, 1, 0

Output

Print the side length of the largest all-ones square submatrix to STDOUT. The answer is guaranteed to be greater than 1.

For the example above, the output is:

Restrictions:60s256Mb 1 Score Packages

Feel free to create an issue if you need an extra library from the standard Ubuntu repository.

Name	Version	Description
libc6-dev	2.39-0ubuntu8.7	GNU C Library: Development Libraries and Header Files Contains the symlinks, headers, and object files needed to compile and link programs which use the standard C library.
libclang-common-14-dev	1:14.0.6-19build4	Clang library - Common development package Clang project is a C, C++, Objective C and Objective C++ front-end based on the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998, 11, 14 and 17 standards and also provides most of the support of C++20. . This package contains the Clang generic headers.
libclang-common-15-dev	1:15.0.7-14build3	Clang library - Common development package Clang project is a C, C++, Objective C and Objective C++ front-end based on the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998, 11, 14 and 17 standards and also provides most of the support of C++20. . This package contains the Clang generic headers.
libclang-common-16-dev	1:16.0.6-23ubuntu4	Clang library - Common development package Clang project is a C, C++, Objective C and Objective C++ front-end based on the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998, 11, 14 and 17 standards and also provides most of the support of C++20. . This package contains the Clang generic headers.
libclang-common-17-dev	1:17.0.6-9ubuntu1	Clang library - Common development package Clang project is a C, C++, Objective C and Objective C++ front-end based on the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998, 11, 14 and 17 standards and also provides most of the support of C++20. . This package contains the Clang generic headers.
libclang-common-18-dev	1:18.1.3-1ubuntu1	Clang library - Common development package Clang project is a C, C++, Objective C and Objective C++ front-end based on the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998, 11, 14 and 17 standards and also provides most of the support of C++20. . This package contains the Clang generic headers.
libclang-common-19-dev	1:19.1.1-1ubuntu1~24.04.2	Clang library - Common development package Clang project is a C, C++, Objective C and Objective C++ front-end based on the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998, 11, 14 and 17 standards and also provides most of the support of C++20. . This package contains the Clang generic headers.
libclang-common-20-dev	1:20.1.2-0ubuntu1~24.04.3	Clang library - Common development package Clang project is a C, C++, Objective C and Objective C++ front-end based on the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998, 11, 14 and 17 standards and also provides most of the support of C++20. . This package contains the Clang generic headers.
libcrypt-dev	1:4.4.36-4build1	libcrypt development files This package contains the files needed for developing applications that use libcrypt.
libgcc-10-dev	10.5.0-4ubuntu2.1	GCC support library (development files) This package contains the headers and static library files necessary for building C programs which use libgcc, libgomp, libquadmath, libssp or libitm.
libgcc-11-dev	11.5.0-1ubuntu1~24.04.1	GCC support library (development files) This package contains the headers and static library files necessary for building C programs which use libgcc, libgomp, libquadmath, libssp or libitm.
libgcc-12-dev	12.4.0-2ubuntu1~24.04.1	GCC support library (development files) This package contains the headers and static library files necessary for building C programs which use libgcc, libgomp, libquadmath, libssp or libitm.
libgcc-13-dev	13.3.0-6ubuntu2~24.04.1	GCC support library (development files) This package contains the headers and static library files necessary for building C programs which use libgcc, libgomp, libquadmath, libssp or libitm.
libgcc-14-dev	14.2.0-4ubuntu2~24.04.1	GCC support library (development files) This package contains the headers and static library files necessary for building C programs which use libgcc, libgomp, libquadmath, libssp or libitm.
libobjc-13-dev	13.3.0-6ubuntu2~24.04.1	Runtime library for GNU Objective-C applications (development files) This package contains the headers and static library files needed to build GNU ObjC applications.
libssl-dev	3.0.13-0ubuntu3.11	Secure Sockets Layer toolkit - development files This package is part of the OpenSSL project's implementation of the SSL and TLS cryptographic protocols for secure communication over the Internet. . It contains development libraries, header files, and manpages for libssl and libcrypto.
libstdc++-10-dev	10.5.0-4ubuntu2.1	GNU Standard C++ Library v3 (development files) This package contains the headers and static library files necessary for building C++ programs which use libstdc++. . libstdc++-v3 is a complete rewrite from the previous libstdc++-v2, which was included up to g++-2.95. The first version of libstdc++-v3 appeared in g++-3.0.
libstdc++-11-dev	11.5.0-1ubuntu1~24.04.1	GNU Standard C++ Library v3 (development files) This package contains the headers and static library files necessary for building C++ programs which use libstdc++. . libstdc++-v3 is a complete rewrite from the previous libstdc++-v2, which was included up to g++-2.95. The first version of libstdc++-v3 appeared in g++-3.0.
libstdc++-12-dev	12.4.0-2ubuntu1~24.04.1	GNU Standard C++ Library v3 (development files) This package contains the headers and static library files necessary for building C++ programs which use libstdc++. . libstdc++-v3 is a complete rewrite from the previous libstdc++-v2, which was included up to g++-2.95. The first version of libstdc++-v3 appeared in g++-3.0.
libstdc++-13-dev	13.3.0-6ubuntu2~24.04.1	GNU Standard C++ Library v3 (development files) This package contains the headers and static library files necessary for building C++ programs which use libstdc++. . libstdc++-v3 is a complete rewrite from the previous libstdc++-v2, which was included up to g++-2.95. The first version of libstdc++-v3 appeared in g++-3.0.
libstdc++-14-dev	14.2.0-4ubuntu2~24.04.1	GNU Standard C++ Library v3 (development files) This package contains the headers and static library files necessary for building C++ programs which use libstdc++. . libstdc++-v3 is a complete rewrite from the previous libstdc++-v2, which was included up to g++-2.95. The first version of libstdc++-v3 appeared in g++-3.0.
libtbb-dev	2021.11.0-2ubuntu2	parallelism library for C++ - development files TBB is a library that helps you leverage multi-core processor performance without having to be a threading expert. It represents a higher-level, task-based parallelism that abstracts platform details and threading mechanism for performance and scalability. . (Note: if you are a user of the i386 architecture, i.e., 32-bit Intel or compatible hardware, this package only supports Pentium4-compatible and higher processors.) . This package includes the TBB development files.

Back to listJan 4, 2026 04:31

Josu San Martin

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Source Code

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Challenge History

Date	Challenger	Cost	Type	Status
Sep 5, 2026 06:03	Tomislav Tunkovic	36.57	Custom	Solution Broken

Run Statistics

#	Date	Score	Wall Time	CPU User	CPU System	Memory	Error
1	Sep 5, 2026 06:25	0	9,441,893	1,232,000	0	2,117,632	expected "2", got "50 "
2	Sep 5, 2026 06:25	0	9,578,413	1,243,000	0	2,117,632	expected "2", got "50 "
3	Sep 5, 2026 06:25	0	9,327,322	1,342,000	0	2,117,632	expected "2", got "50 "
4	Jan 4, 2026 04:31	4,233	16,479,097	0	1,693,000	2,437,120
5	Jan 4, 2026 04:44	4,235	18,563,100	1,694,000	0	2,445,312
6	Jan 4, 2026 04:31	4,285	20,474,425	0	1,714,000	2,441,216
7	Jan 4, 2026 04:44	4,305	19,617,000	0	1,722,000	2,449,408
8	Jan 4, 2026 04:44	4,320	21,827,020	0	1,728,000	2,445,312
9	Jan 4, 2026 04:35	4,323	20,498,243	0	1,729,000	2,445,312
10	Jan 4, 2026 04:44	4,338	18,932,226	0	1,735,000	2,445,312
11	Jan 4, 2026 04:35	4,353	15,001,934	0	1,741,000	2,445,312
12	Jan 4, 2026 04:44	4,358	17,588,194	0	1,743,000	2,445,312
13	Jan 4, 2026 04:44	4,370	19,127,618	0	1,748,000	2,449,408
14	Jan 4, 2026 04:35	4,375	16,458,057	0	1,750,000	2,535,424
15	Jan 4, 2026 04:35	4,378	19,840,282	0	1,751,000	2,441,216
16	Jan 4, 2026 04:31	4,400	14,585,035	0	1,760,000	2,441,216
17	Jan 4, 2026 04:35	4,408	19,862,231	0	1,763,000	2,445,312
18	Jan 4, 2026 04:44	4,408	18,672,227	0	1,763,000	2,441,216
19	Jan 4, 2026 04:31	4,428	15,524,895	0	1,771,000	2,445,312
20	Jan 4, 2026 04:35	4,435	16,041,367	0	1,774,000	2,277,376
21	Jan 4, 2026 04:31	4,463	19,611,202	1,785,000	0	2,437,120
22	Jan 4, 2026 04:31	4,773	20,642,330	1,909,000	0	2,441,216
23	Jan 4, 2026 04:35	4,783	22,327,266	0	1,913,000	2,441,216
24	Jan 4, 2026 04:31	4,790	19,587,565	958,000	958,000	2,445,312
25	Jan 4, 2026 04:44	4,795	20,331,689	0	1,918,000	2,445,312
26	Jan 4, 2026 04:31	4,795	21,393,661	0	1,918,000	2,449,408
27	Jan 4, 2026 04:35	4,805	17,524,211	961,000	961,000	2,523,136
28	Jan 4, 2026 04:44	4,815	17,323,062	963,000	963,000	2,453,504
29	Jan 4, 2026 04:35	4,888	14,889,160	1,955,000	0	2,506,752
30	Jan 4, 2026 04:31	5,115	25,487,727	0	2,046,000	2,441,216

Model	Intel(R) Xeon(R) CPU E3-1271 v3 @ 3.60GHz
Cores	1