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 listNov 8, 2026 06:11highload-churnerhighload-churnerScore: 2,122Success
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Run Statistics
#DateScoreWall TimeCPU UserCPU SystemMemoryError
1Nov 8, 2026 06:121,7109,626,915684,000024,576stderr
2Nov 8, 2026 06:121,73210,134,665693,000024,576stderr
3Nov 8, 2026 06:122,0659,770,784826,000024,576stderr
4Nov 8, 2026 06:122,10012,128,420840,000024,576stderr
5Nov 8, 2026 06:122,1229,908,396849,000024,576stderr
6Nov 8, 2026 06:122,1229,867,018849,000024,576stderr
7Nov 8, 2026 06:122,1509,905,644860,000024,576stderr
8Nov 8, 2026 06:122,1609,886,469864,000024,576stderr
9Nov 8, 2026 06:122,47710,037,779991,000024,576stderr