Dividing the matrices into submarines

[morde]

N is the size of the matrix, K is the size of the submarine.
The matrix is further introduced
Accept N = 3, K = 2

Our N*N matrix.

1 2 1
1 1 2
1 1 1

All size submarines K*K:

[1 2
 1 1]
[2 1

1 2]
[1 1

1 1]
[1 2

1 1]

How do you do the same job finding a submarine? What do you want me to do?
The only thing you've done is create a three-dimensional set of k*k matrices filled with zeros.

[carriann]

If in the forehead,

matrix = [[1, 2, 3, 'a'], [4, 5, 6, 'b'], [7, 8, 9, 'c'], [10, 11, 12, 'd']]
size = (3, 2)
for j in range(len(matrix) - size[1] + 1):

for i in range(len(matrix[j]) - size[0] + 1):

for y in range(size[1]):

line = []

for x in range(size[0]):

line.append(matrix[j + y][i + x])

print(line)

print()

In a blatant way, you have to go through the matrix so that one element of the submarine is within the range: matrix_width - submatrix_width♪ matrix_height - submatrix_height

And then using the coordinates of the first element, find all the other submarine elements in the matrix.

or if it is written at the formula level, then:

submatrix[x][y] = matrix[i + x][j + y]

where (i, j) is the coordinates of the first (left top) submarine element in the matrix

P. S.

The code can be slightly simplified (for disgusts):

[[[print([matrix[j + y][i + x] for x in range(size[0])]) for y in range(size[1])] + [print()] for i in range(len(matrix[j]) - size[0] + 1)] for j in range(len(matrix) - size[1] + 1)]