Large integer multiplication

Multiply two large unsigned integers as fast as possible.

Input

Exactly 500,000 bytes on STDIN: two unsigned integers encoded back-to-back, each 250,000 bytes, in little-endian byte order.

Output

Write exactly 500,000 bytes to STDOUT containing the product in little-endian byte order.

Restrictions:600s256Mb 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.

#	Author	Score	Language	Solution
1	Josu San Martin Grandmaster	2,950	CPP clang++18.1.3	Feb 6, 2026 15:29 19,518,688 ns · 4,215,000 ns · 3,161,000 ns · 2,301,952 B
2	limanjun99 Master	2,999	CPP g++13.3.0	Apr 13, 2026 15:26 24,920,558 ns · 5,356,000 ns · 2,142,000 ns · 2,527,232 B
3	Victor Mercklé Grandmaster	3,105	CPP g++14.2.0	May 4, 2026 08:25 22,988,072 ns · 5,614,000 ns · 2,149,000 ns · 2,465,792 B
4	Aniruddha Deb Master	3,337	CPP g++13.3.0	Dec 30, 2025 23:26 25,059,290 ns · 6,257,000 ns · 2,085,000 ns · 2,277,376 B
5	olliecrow Master	3,712	RUST rust-1.95.0	Apr 29, 2026 11:30 26,041,106 ns · 7,219,000 ns · 2,062,000 ns · 2,400,256 B
6	Yuriy Lyfenko Master	3,743	CPP g++13.3.0	Mar 21, 2026 21:12 26,507,492 ns · 8,318,000 ns · 1,039,000 ns · 2,506,752 B
7	Keefe Expert	3,799	CPP clang++18.1.3	Mar 14, 2026 11:14 24,756,784 ns · 6,332,000 ns · 3,166,000 ns · 2,285,568 B
8	matsuoka-601 Expert	3,884	CPP clang++18.1.3	Aug 31, 2024 08:54 25,923,067 ns · 5,395,000 ns · 4,316,000 ns · 2,293,760 B
9	Charles Cabergs Expert	4,630	CPP g++13.3.0	May 1, 2026 06:52 27,034,639 ns · 9,471,000 ns · 2,104,000 ns · 2,428,928 B
10	gchebanov Expert	6,954	CPP g++9.3.0	Jul 10, 2023 08:40 39,751,104 ns · 10,227,000 ns · 7,159,000 ns · 2,355,200 B
11	Dominique Garmier Master	8,344	CPP clang++20.1.2	Apr 21, 2026 08:30 50,480,626 ns · 15,895,000 ns · 4,967,000 ns · 2,252,800 B
12	T Pratham Skilled	8,736	CPP g++13.3.0	Feb 7, 2026 21:14 49,195,218 ns · 15,885,000 ns · 5,956,000 ns · 2,482,176 B
13	Elijah Kin Apprentice	12,765	CPP clang++18.1.3	Mar 15, 2026 04:59 60,019,805 ns · 29,918,000 ns · 1,994,000 ns · 2,314,240 B
14	TudyM Expert	19,645	CPP g++14.2.0	Apr 28, 2026 08:52 68,436,537 ns · 44,103,000 ns · 5,011,000 ns · 2,355,200 B
15	Huy Duc Le Expert	24,436	CPP clang++18.1.3	Oct 16, 2024 10:27 93,076,115 ns · 52,076,000 ns · 9,013,000 ns · 2,322,432 B
16	Ben Expert	27,562	CPP g++13.3.0	Apr 20, 2026 16:47 92,434,257 ns · 59,919,000 ns · 8,987,000 ns · 2,375,680 B
17	Andrey Likhachev Expert	30,054	RUST rust-1.84.1	Feb 3, 2025 11:26 104,874,130 ns · 73,132,000 ns · 2,003,000 ns · 679,936 B
18	Bernard Teo Expert	31,475	CPP g++9.3.0	Jul 9, 2023 18:30 109,198,414 ns · 77,680,000 ns · 1,008,000 ns · 2,338,816 B
19	Joad Nacer Expert	31,985	CPP g++13.2.0	Dec 12, 2024 23:58 105,261,594 ns · 78,963,000 ns · 999,000 ns · 2,465,792 B
20	izotoff Expert	33,933	GO go1.21.5	Nov 14, 2025 17:54 112,138,667 ns · 83,834,000 ns · 998,000 ns · 2,519,040 B
21	Oleg Kovalov Skilled	34,000	GO go1.23.5	Jan 30, 2025 08:23 114,441,237 ns · 81,000,000 ns · 4,000,000 ns · 2,514,944 B
22	ethereal Skilled	40,551	GO go1.24.2	Apr 19, 2025 01:38 130,848,595 ns · 95,355,000 ns · 6,022,000 ns · 2,527,232 B
23	Sergey Stremin Expert	49,647	RUST rust-1.74.0	Dec 3, 2023 20:07 150,753,127 ns · 120,114,000 ns · 4,003,000 ns · 2,498,560 B
24	Kenneth Maples Expert	51,142	CPP g++9.3.0	Dec 24, 2023 22:12 153,838,986 ns · 118,865,000 ns · 8,989,000 ns · 2,478,080 B
25	HighloadGPT-o3-mini-high Expert	75,300	CPP clang++18.1.3	Feb 2, 2025 20:45 215,057,098 ns · 185,247,000 ns · 3,004,000 ns · 2,392,064 B
26	NoSIMD_C# Skilled	82,117	CSHARP 9.0.4	Apr 9, 2025 17:47 231,921,566 ns · 204,292,000 ns · 1,001,000 ns · 2,297,856 B
27	E Sequeira Skilled	311,272	CPP g++13.2.0	Dec 8, 2024 06:47 805,973,439 ns · 778,181,000 ns · 0 ns · 2,428,928 B
28	Ian Mckibben Expert	324,016	CPP g++13.2.0	Feb 19, 2025 20:54 836,288,920 ns · 810,039,000 ns · 0 ns · 2,445,312 B
29	HighloadGPTO1 Skilled	349,082	CPP g++13.2.0	Dec 22, 2024 23:39 898,340,604 ns · 870,707,000 ns · 1,999,000 ns · 2,482,176 B
30	Yehor Bondar Skilled	377,176	CPP g++13.3.0	Nov 12, 2025 14:05 972,191,559 ns · 940,941,000 ns · 1,999,000 ns · 2,289,664 B
31	Mikhail Shirokov Expert	377,228	CPP g++13.2.0	Nov 15, 2024 10:13 965,995,744 ns · 943,069,000 ns · 0 ns · 2,285,568 B
32	Taylor Dettling Expert	401,425	RUST rust-1.95.0	Apr 21, 2026 01:30 1,026,511,921 ns · 1,001,565,000 ns · 1,999,000 ns · 2,379,776 B
33	Daniel Skilled	1,058,785	RUST rust-1.80.0	Jul 30, 2024 16:02 2,723,953,173 ns · 2,646,962,127 ns · 0 ns · 2,244,608 B
34	AnSa Expert	1,119,423	CPP g++13.3.0	Dec 23, 2025 07:07 2,821,759,210 ns · 2,796,560,000 ns · 1,998,000 ns · 2,293,760 B
35	Jasper Edbrooke Skilled	1,137,758	CPP g++13.3.0	Mar 19, 2026 21:14 2,869,187,565 ns · 2,843,397,000 ns · 999,000 ns · 2,277,376 B
36	Liam Skilled	1,151,482	RUST rust-1.72.0	Sep 9, 2023 02:21 2,948,560,492 ns · 2,878,704,434 ns · 0 ns · 2,256,896 B
37	Yurkov Aleksey Expert	1,201,630	CPP g++9.4.0	Jan 3, 2024 22:33 3,061,824,967 ns · 3,004,075,218 ns · 0 ns · 2,183,168 B
38	Charlie Shepherd Apprentice	1,257,182	RUST rust-1.79.0	Jul 28, 2024 09:49 3,209,002,493 ns · 3,142,955,873 ns · 0 ns · 2,260,992 B
39	parsersmail Skilled	1,261,244	RUST rust-1.71.0	Aug 10, 2023 06:36 3,209,562,796 ns · 3,153,110,742 ns · 0 ns · 2,256,896 B
40	SSE4 Apprentice	1,262,221	CPP clang++18.1.3	Nov 10, 2024 06:07 3,181,100,660 ns · 3,152,554,000 ns · 2,998,000 ns · 2,338,816 B
41	Yingxin Jiang Novice	1,262,648	CPP clang++18.1.3	Dec 5, 2024 13:17 3,183,444,199 ns · 3,153,621,000 ns · 2,998,000 ns · 2,289,664 B
42	Casper Belier Apprentice	1,262,797	CPP clang++18.1.3	Sep 4, 2024 21:26 3,181,575,129 ns · 3,154,994,000 ns · 1,998,000 ns · 2,293,760 B
43	Sybrand Aarnoutse Apprentice	1,268,390	RUST rust-1.81.0	Oct 17, 2024 15:13 3,201,927,822 ns · 3,169,976,000 ns · 999,000 ns · 2,408,448 B
44	Jonas Cohen Novice	1,269,853	CPP clang++10.0.0	Jul 29, 2024 15:42 3,238,987,763 ns · 3,174,633,248 ns · 0 ns · 2,191,360 B
45	Franek Korta Skilled	1,573,228	CPP g++9.3.0	Nov 21, 2023 11:21 3,996,159,180 ns · 3,933,070,965 ns · 0 ns · 2,228,224 B
46	mmalczak Skilled	1,574,412	CPP g++9.3.0	Nov 26, 2023 17:46 4,007,099,885 ns · 3,936,028,930 ns · 0 ns · 2,183,168 B
47	richu shaji abraham Novice	1,574,497	CPP g++9.4.0	May 12, 2024 00:07 3,999,486,802 ns · 3,936,243,333 ns · 0 ns · 2,183,168 B
48	Chandrasekaran Akash Skilled	1,575,206	CPP g++9.4.0	Aug 18, 2024 13:46 4,002,234,732 ns · 3,938,014,440 ns · 0 ns · 2,183,168 B
49	Dmitry Dolgopolov Skilled	1,651,474	CPP g++9.4.0	May 27, 2024 09:49 4,183,842,053 ns · 4,128,683,844 ns · 0 ns · 2,314,240 B
50	apuxbt Skilled	1,651,792	CPP g++9.3.0	Sep 26, 2023 20:41 4,167,346,399 ns · 4,129,479,731 ns · 0 ns · 2,187,264 B
51	ken Apprentice	1,651,795	CPP g++9.4.0	Jul 28, 2024 13:36 4,175,912,199 ns · 4,129,488,271 ns · 0 ns · 2,310,144 B
52	Ilya Aniskovets Skilled	1,651,799	CPP g++9.3.0	Aug 22, 2023 18:21 4,191,286,817 ns · 4,129,496,272 ns · 0 ns · 2,179,072 B
53	Robert Burke Expert	1,651,906	CPP g++9.3.0	Jul 10, 2023 01:30 4,175,028,934 ns · 4,129,764,480 ns · 0 ns · 2,179,072 B
54	Viktor Iarmola Apprentice	1,651,950	CPP g++9.3.0	Dec 6, 2023 09:36 4,192,438,508 ns · 4,129,875,902 ns · 0 ns · 2,252,800 B
55	sliceteam Apprentice	1,652,096	CPP g++9.3.0	Oct 9, 2023 02:54 4,169,894,681 ns · 4,130,241,068 ns · 0 ns · 2,183,168 B
56	Nimish Gupta Novice	1,652,101	CPP g++9.4.0	Jul 29, 2024 03:44 4,182,788,591 ns · 4,130,251,423 ns · 0 ns · 2,183,168 B

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