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 20, 2026 05:11highload-churnerhighload-churnerError
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Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Oct 20, 2026 05:11010,072,993716,000020,480expected "80", got "st51_tr99_mm143_ma60_fa177_gp22_50............. "
2Oct 20, 2026 05:1109,708,108713,000020,480expected "50", got "st55_tr97_mm118_ma70_fa171_gp22_50............. "
3Oct 20, 2026 05:11010,118,779719,000020,480expected "79", got "st52_tr101_mm122_ma60_fa168_gp22_50............ "