For questions like: (Rat in a maze) In 2-d matrix, given starting point and destination point.. with some points blocked or something, you have to calculate number of paths to reach destination ( given 4 types of moves)... Can I apply DP with it? Memorizing the state Dp[x][y], and using it if i visit that node again??

When i backtrack, how do i un-visit that node and alter DP table with that?

For Eg: [problem:https://mirror.codeforces.com/contest/540/problem/C] or [problem:https://mirror.codeforces.com/contest/374/problem/C]

Any help will be much appreciated. Thanks a lot :)