here the function will return the max blocks that can be covered by the knight ( from best path)
and then in main function i have subtracted total blocks - blocks that can be travelled.
Funky chessboard
can you explain me your logic (provide some comments in your code ) it will be easier for me to understand , i can explain you a similar and logic for this problem as your code
what you need to do is once you visit a cell, then visit all the cells that can be visited from this cell and also visit the cells that can be further visited from the next reachable cells.
check code here , i have explained the logic along with the code :-
In case of any doubt feel free to ask 
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