Week 6: Monday
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Q1. (40)

Write a program that outputs all possible sub-matrices from a matrix of size n
by m. The sub-matrices must be such that its rows and columns are adjacent.
Avoid outputting sub-matrices having only one row or one column.

Example:

If the matrix (of size 2 by 3) is

1	2	3
4	5	6

the sub-matrices that should be output are

1	2
4	5

and

2	3
5	6

Q2. (60)

Write a recursive function to calculate the number of configuration of n rooks
on an n-by-n chessboard such that no two rooks can capture each other in the
next move (i.e., no two rooks lie on the same row or same column). You cannot
output a configuration where all the rooks are on the main diagonal or all of
them are on the main cross-diagonal.

Write a main function to test it.

(Note that the answer can be calculated analytically. Do not do that. Instead,
calculate this number using recursion.)