suppose

```
A(n,m) =
1 2 3
4 5 6
7 8 9
and
B(p, q) =
1 1
1 1
```

What is best method to find min of square of difference of sub-matrices of A and B e.g.

sub-matrices of A =

```
1 2 | 2 3 | 4 5 | 5 6
3 4 | 5 6 | 7 8 | 8 9
```

Difference of first sub-matrix of A with B =

```
(1-1) (2-1) = | 0 1
(3-1) (4-1) | 2 3
```

sum of square of elements = `0*0 + 1*1 + 2*2 + 3*3 = 14`

similar steps for other sub-matrices of A

Please suggest looking for an alternate method or algorithm which has time complexity less than `O(n*m*p*q)`