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 listMar 15, 2026 10:27

Dominique Garmier

Score: 58,008

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Run Statistics

#	Date	Score	Wall Time	CPU User	CPU System	Memory
1	Mar 15, 2026 10:17	31,543	31,966,457	11,566,000	1,051,000	2,289,664
2	Mar 15, 2026 10:46	31,675	30,673,746	11,615,000	1,055,000	2,289,664
3	Mar 15, 2026 10:17	31,765	36,893,582	11,648,000	1,058,000	2,260,992
4	Mar 15, 2026 10:17	32,240	29,760,710	11,904,000	992,000	2,289,664
5	Mar 15, 2026 10:17	33,638	31,177,717	12,420,000	1,035,000	2,260,992
6	Mar 15, 2026 10:17	34,348	31,546,467	13,739,000	0	2,289,664
7	Mar 20, 2026 08:04	36,505	31,797,600	13,559,000	1,043,000	2,260,992
8	Mar 15, 2026 10:39	37,263	35,662,013	14,905,000	0	2,514,944
9	Mar 15, 2026 10:17	38,258	40,773,607	13,263,000	2,040,000	2,281,472
10	Mar 15, 2026 10:39	39,278	42,188,742	14,664,000	1,047,000	2,289,664
11	Mar 15, 2026 10:41	40,180	46,820,619	15,068,000	1,004,000	2,289,664
12	Mar 15, 2026 10:35	41,865	42,573,670	15,700,000	1,046,000	2,519,040
13	Mar 15, 2026 10:17	43,583	43,404,763	16,408,000	1,025,000	2,289,664
14	Mar 15, 2026 10:33	45,003	47,126,372	17,001,000	1,000,000	2,285,568
15	Mar 15, 2026 10:39	47,438	44,863,428	16,978,000	1,997,000	2,506,752
16	Mar 15, 2026 10:35	54,903	44,965,493	19,965,000	1,996,000	2,506,752
17	Mar 15, 2026 10:33	55,123	49,336,411	20,045,000	2,004,000	2,289,664
18	Mar 15, 2026 10:41	57,748	47,694,562	22,095,000	1,004,000	2,359,296
19	Mar 15, 2026 10:39	58,008	50,793,104	22,195,000	1,008,000	2,265,088
20	Mar 15, 2026 10:17	59,678	49,722,149	21,882,000	1,989,000	2,289,664
21	Mar 15, 2026 10:39	60,368	49,667,584	22,135,000	2,012,000	2,260,992
22	Mar 15, 2026 10:27	60,485	58,171,491	22,178,000	2,016,000	2,289,664
23	Mar 15, 2026 10:17	60,853	51,975,216	22,313,000	2,028,000	2,519,040
24	Mar 20, 2026 08:04	60,890	52,405,336	22,327,000	2,029,000	2,289,664
25	Mar 15, 2026 10:23	61,073	50,473,692	22,394,000	2,035,000	2,289,664
26	Mar 15, 2026 10:39	61,158	49,911,932	24,463,000	0	2,289,664
27	Mar 15, 2026 10:46	61,593	49,091,744	23,611,000	1,026,000	2,519,040
28	Mar 15, 2026 10:23	61,718	53,742,586	23,659,000	1,028,000	2,289,664
29	Mar 15, 2026 10:46	62,188	49,150,881	23,880,000	995,000	2,269,184
30	Mar 15, 2026 10:23	62,190	52,247,180	22,886,000	1,990,000	2,289,664
31	Mar 15, 2026 10:27	62,215	51,579,400	23,891,000	995,000	2,375,680
32	Mar 15, 2026 10:27	62,260	49,381,318	22,912,000	1,992,000	2,355,200
33	Mar 20, 2026 08:04	62,300	50,989,063	22,927,000	1,993,000	2,289,664
34	Mar 15, 2026 10:41	63,493	46,670,286	24,382,000	1,015,000	2,371,584
35	Mar 15, 2026 10:33	63,513	50,864,266	24,389,000	1,016,000	2,289,664
36	Mar 15, 2026 10:35	65,165	54,027,796	24,061,000	2,005,000	2,289,664

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