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Problem 782


Problem 782


Distinct Rows and Columns

The complexity of an n×n binary matrix is the number of distinct rows and columns.

For example, consider the 3×3 matrices
A=(101000101)B=(000000111)
A has complexity 2 because the set of rows and columns is 000,101.

B has complexity 3 because the set of rows and columns is 000,001,111.

For 0kn2, let c(n,k) be the minimum complexity of an n×n binary matrix with exactly k ones.

Let
C(n)=k=0n2c(n,k)
For example, C(2)=c(2,0)+c(2,1)+c(2,2)+c(2,3)+c(2,4)=1+2+2+2+1=8.

You are given C(5)=64, C(10)=274 and C(20)=1150.

Find C(104).


不同的行与列

对于一个n×n01矩阵,其复杂度等于其不同的行与列的数量。

例如,考虑如下的3×3矩阵
A=(101000101)B=(000000111)
A的复杂度为2,因为它不同的行与列构成的集合为000,101

B的复杂度为3,因为它不同的行与列构成的集合为000,001,111

对于0kn2,记c(n,k)n×n01矩阵中,包含恰好k1的此类矩阵的最小复杂度。


C(n)=k=0n2c(n,k)
例如,C(2)=c(2,0)+c(2,1)+c(2,2)+c(2,3)+c(2,4)=1+2+2+2+1=8

已知C(5)=64C(10)=274C(20)=1150

C(104)


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