zeref_dragoneel's blog

number of rectangular submatrix with all 1s
By zeref_dragoneel, history, 10 years ago, In English

How to count the number of rectanglular submatrix with all 1s in a binary square matrix of size N in O(N^2)?

i have a solution for o(N^3)

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10 years ago, hide # |
 
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Nice question! Like you, i am only solving the O(N^3) algorithm with two pointer technique, and i guess O(N^2 Log N) with divide and conquer maybe..

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10 years ago, hide # |
 
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Test your idea with this problem from COCI. My O(N^2 Log N) idea get TLE.

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