TapeEquilibrium Java Implementation
Time complexity

The solution doesn't meet the required \$O(N)\$ complexity.
Can you spot why?


       Collections.sort(list);


As it stands, the time complexity of your implementation is \$O(N\log N)\$. To get the minimum element of a collection, do you really need to sort all the elements?

Unused values, unnecessary complication

The p field of Holder is not used in the compareTo implementation.
In general, it's suspicious when a class implements Comparable but compareTo doesn't use all the fields of the class.
In fact this field is not used anywhere in the program.
So you can simplify by removing it.
And once this field is gone,
Holder will have only one field left.
A class with a single field in it is highly suspicious.
Is it really useful?

With Holder eliminated, the implementation can become much simpler, cleaner and faster.