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 listOct 3, 2026 03:58Karthik ReddyKarthik ReddyError
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Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Oct 3, 2026 03:58012,954,05602,499,0002,121,728expected "50", got "pread 1347 mmap 30 touch 312 pmd 0 rss 0 fs 1021994 s0 "
2Oct 3, 2026 03:58012,917,72302,612,0002,121,728expected "54", got "pread 1353 mmap 28 touch 275 pmd 0 rss 0 fs 1021994 s0 "
3Oct 3, 2026 03:58013,424,72302,511,0002,121,728expected "72", got "pread 1362 mmap 35 touch 280 pmd 0 rss 0 fs 1021994 s0 "