There is a problem I couldn't solve which is from Turkish olympiad (Yeni Sistemli Kollege Olympiad in Informatics 2016 Semi-Final).
I have link of the problem, but you have to register into site to see problem: http://www.koduesi.com/en/Arena/Practice/14/1142
Here is statement of problem if you don't want to register:
A maze is specified by a matrix of characters with dimensions M and N:
– The walls are denoted with 'x' characters.
– The empty fields are denoted with ' ' (space) characters.
– The starting point is specified with the character 'S'.
– The exit point is specified with an empty field at the outer wall of the maze.
Count all simple paths (CNT) through the maze from the starting point to the exit point.
Note: A simple path doesn’t pass twice through the same matrix field.
5 ≤ M ≤ 20
10 ≤ N ≤ 50
Here is sample test: http://ideone.com/kqVPxy
It seems very standart problem, but I couldn't find it. Thanks in advance!