Largest Square Submatrix of all 1's Haha Expert

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:

2
Back to listJun 8, 2026 13:57Victor MerckléVictor MerckléError
Source Code

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Challenge History
DateChallengerCostTypeStatus
Sep 4, 2026 13:02Tomislav Tunkovic48.81CustomSolution Broken
Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Sep 4, 2026 13:1109,099,0751,093,00002,113,536expected "2", got "50 "
2Jun 8, 2026 13:582,0128,191,820805,00002,113,536
3Jun 8, 2026 13:582,3028,148,064921,00002,113,536
4Jun 8, 2026 13:582,3228,176,585929,00002,113,536
5Jun 8, 2026 13:582,3458,343,495938,00002,113,536
6Jun 8, 2026 13:582,3708,563,530948,00002,113,536
7Jun 8, 2026 13:582,5678,303,5481,027,00002,113,536
8Jun 8, 2026 13:582,7028,335,3861,081,00002,113,536
9Jun 8, 2026 13:582,7028,328,3171,081,00002,113,536
10Jun 8, 2026 13:582,7878,425,2871,115,00002,113,536
11Sep 4, 2026 13:112,79011,262,3211,116,00002,113,536
12Sep 4, 2026 13:115,10710,906,6152,043,00002,113,536