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 06:07

Josu San Martin

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Source Code

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Challenge History

Date	Challenger	Cost	Type	Status
Jul 5, 2026 22:55	Victor Mercklé	10.00	Custom	Solution Broken

Run Statistics

#	Date	Score	Wall Time	CPU User	CPU System	Memory	Error
1	Jul 5, 2026 22:56	0	8,876,507	1,137,000	0	2,117,632	expected "51", got "50 "
2	Jul 5, 2026 22:56	0	10,109,265	1,142,000	0	2,117,632	expected "51", got "50 "
3	Jul 5, 2026 22:56	2,617	8,895,995	1,047,000	0	2,117,632
4	Jan 4, 2026 06:11	3,700	19,907,880	1,480,000	0	2,441,216
5	Jan 4, 2026 06:00	3,705	17,944,764	0	1,482,000	2,445,312
6	Jan 4, 2026 06:03	3,705	23,170,716	1,482,000	0	2,445,312
7	Jan 4, 2026 06:03	3,720	15,517,611	1,488,000	0	2,445,312
8	Jan 4, 2026 06:03	3,730	16,695,782	0	1,492,000	2,445,312
9	Jan 4, 2026 18:01	3,763	13,565,626	1,505,000	0	2,449,408
10	Jan 4, 2026 06:00	3,765	15,533,119	1,506,000	0	2,453,504
11	Jan 4, 2026 06:00	3,800	12,737,236	1,520,000	0	2,441,216
12	Jan 4, 2026 06:03	3,833	16,238,200	1,533,000	0	2,445,312
13	Jan 4, 2026 06:00	3,843	17,409,712	0	1,537,000	2,445,312
14	Jan 4, 2026 18:01	3,855	19,008,634	1,542,000	0	2,449,408
15	Jan 4, 2026 06:07	3,863	15,304,874	1,545,000	0	2,449,408
16	Jan 4, 2026 18:01	3,870	20,228,509	1,548,000	0	2,449,408
17	Jan 4, 2026 06:11	3,875	16,654,898	1,550,000	0	2,445,312
18	Jan 4, 2026 06:03	3,890	20,013,985	1,556,000	0	2,445,312
19	Jan 4, 2026 06:10	3,893	15,490,366	1,557,000	0	2,441,216
20	Jan 4, 2026 06:10	3,895	19,707,711	0	1,558,000	2,445,312
21	Jan 4, 2026 06:00	3,905	16,302,094	1,562,000	0	2,453,504
22	Jan 4, 2026 06:00	3,908	19,262,277	1,563,000	0	2,445,312
23	Jan 4, 2026 06:00	3,910	20,918,856	1,564,000	0	2,433,024
24	Jan 4, 2026 06:07	3,945	21,939,373	1,578,000	0	2,445,312
25	Jan 4, 2026 06:00	3,983	22,922,755	0	1,593,000	2,535,424
26	Jan 4, 2026 06:11	4,013	20,705,662	1,605,000	0	2,449,408
27	Jan 4, 2026 06:03	4,035	22,185,883	1,614,000	0	2,441,216
28	Jan 4, 2026 06:03	4,040	15,189,195	1,616,000	0	2,449,408
29	Jan 4, 2026 06:03	4,055	19,324,518	1,622,000	0	2,445,312
30	Jan 4, 2026 06:07	4,075	23,115,569	1,630,000	0	2,445,312
31	Jan 4, 2026 06:10	4,105	23,617,833	1,642,000	0	2,445,312
32	Jan 4, 2026 06:00	4,150	24,274,951	0	1,660,000	2,449,408
33	Jan 4, 2026 06:03	4,170	17,805,594	0	1,668,000	2,445,312

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