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	1:20.1.2-0ubuntu1~24.04.2	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.
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	3.0.13-0ubuntu3.9	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 5, 2026 02:42

Josu San Martin

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Challenge History

Date	Challenger	Cost	Type	Status
May 17, 2026 14:20	M-Rochat	10.00	Custom	Solution Broken

Run Statistics

#	Date	Score	Wall Time	CPU User	CPU System	Memory	Error
1	May 17, 2026 14:57	0	12,095,019	1,003,000	0	2,117,632	expected "307", got "100 "
2	May 17, 2026 14:57	0	8,507,321	984,000	0	2,117,632	expected "307", got "100 "
3	May 17, 2026 14:57	0	11,148,302	1,002,000	0	2,117,632	expected "307", got "100 "
4	Jan 5, 2026 02:40	3,650	17,169,071	1,460,000	0	2,535,424
5	Jan 5, 2026 02:39	3,653	24,154,067	1,461,000	0	2,453,504
6	Jan 5, 2026 02:42	3,665	21,331,786	1,466,000	0	2,453,504
7	Jan 5, 2026 02:38	3,675	21,631,258	0	1,470,000	2,449,408
8	Jan 5, 2026 02:42	3,683	20,748,054	1,473,000	0	2,449,408
9	Jan 5, 2026 02:41	3,695	17,291,932	1,478,000	0	2,453,504
10	Jan 5, 2026 04:39	3,705	13,311,822	1,482,000	0	2,453,504
11	Jan 5, 2026 02:41	3,705	12,797,871	0	1,482,000	2,277,376
12	Jan 5, 2026 02:38	3,705	18,673,274	1,482,000	0	2,449,408
13	Jan 5, 2026 02:41	3,720	18,413,846	1,488,000	0	2,445,312
14	Jan 5, 2026 02:38	3,723	19,697,313	0	1,489,000	2,445,312
15	Jan 5, 2026 02:42	3,730	18,262,968	1,492,000	0	2,445,312
16	Jan 5, 2026 02:40	3,733	16,397,344	0	1,493,000	2,441,216
17	Jan 5, 2026 02:42	3,733	17,039,911	1,493,000	0	2,531,328
18	Jan 5, 2026 02:34	3,733	21,191,787	0	1,493,000	2,445,312
19	Jan 5, 2026 02:42	3,738	19,188,494	0	1,495,000	2,441,216
20	Jan 5, 2026 02:40	3,738	18,765,647	1,495,000	0	2,453,504
21	Jan 5, 2026 02:34	3,740	13,805,434	1,496,000	0	2,445,312
22	Jan 5, 2026 02:40	3,753	22,167,115	1,501,000	0	2,449,408
23	Jan 5, 2026 02:42	3,758	15,044,948	1,503,000	0	2,441,216
24	Jan 5, 2026 02:39	3,765	20,527,943	1,506,000	0	2,453,504
25	Jan 5, 2026 02:42	3,773	16,843,477	1,509,000	0	2,445,312
26	Jan 5, 2026 02:39	3,775	16,121,885	1,510,000	0	2,441,216
27	Jan 5, 2026 02:34	3,785	20,968,109	1,514,000	0	2,449,408
28	Jan 5, 2026 02:41	3,785	17,833,178	1,514,000	0	2,445,312
29	Jan 5, 2026 02:32	3,788	15,686,447	1,515,000	0	2,449,408
30	Jan 5, 2026 02:38	3,803	20,879,890	1,521,000	0	2,449,408
31	Jan 5, 2026 02:38	3,810	18,970,719	1,524,000	0	2,445,312
32	Jan 5, 2026 02:41	3,820	17,984,667	1,528,000	0	2,449,408
33	Jan 5, 2026 04:39	3,850	19,499,588	1,540,000	0	2,445,312
34	Jan 5, 2026 02:32	3,863	17,432,290	1,545,000	0	2,441,216
35	Jan 5, 2026 04:39	3,873	15,072,689	1,549,000	0	2,535,424
36	Jan 5, 2026 02:38	3,898	19,522,592	1,559,000	0	2,445,312
37	Jan 5, 2026 02:33	3,933	15,251,854	1,573,000	0	2,457,600
38	Jan 5, 2026 02:40	3,955	15,074,853	1,582,000	0	2,449,408
39	Jan 5, 2026 02:32	4,020	14,397,985	1,608,000	0	2,449,408
40	Jan 5, 2026 02:41	4,033	20,216,939	0	1,613,000	2,535,424
41	Jan 5, 2026 02:33	4,035	17,327,993	1,614,000	0	2,535,424
42	Jan 5, 2026 02:42	4,045	23,894,117	1,618,000	0	2,453,504
43	Jan 5, 2026 02:42	4,083	17,604,815	1,633,000	0	2,437,120
44	Jan 5, 2026 02:40	4,108	19,290,161	0	1,643,000	2,445,312
45	Jan 5, 2026 02:33	4,268	20,338,369	0	1,707,000	2,441,216

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