Your code is failing on test case :

n = 6

1 4 2 3 6 5

4 2 1 6 5 3

Expected output : 4

Your output : 2

Your logic is little wrong, your code is just checking for cases when groups like ((1,2),(2,1)) are present but fail when multiple groups of type ((1,3,2),(3,2,1)) exists in the grid.

Check out my submission , you will find out your mistake in your code by own.

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