Problem 53950. Time reverse indices

Time reverse the index values as follows
IndexIn = [7 1 0]
IndexOut = [7 6 0]
Note that the indices are zero based and sorted from largest to smallest.
You can think of this as a time reversal of a vector:
[7 1 0] --> [1 1 0 0 0 0 0 1 ]
[7 6 0] --> [1 0 0 0 0 0 1 1 ]
Here is a second example
[8 4 3 2 0] --> [ 1 0 1 1 1 0 0 0 1 ]
[8 6 5 4 0] --> [ 1 0 0 0 1 1 1 0 1 ]
Background of problem. The index defines the tap positions (or characteristic polynomial) of a Linear Feedback Shift Register (LFSR). When the polynomial is primitive, the LFSR goes through all possible states before repeating, thus creating a psuedo random binary sequence (PRBS). A curious property is that if the tap positions are reversed, as we are doing in this problem, then the output sequence is also reversed.
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76.0% Correct | 24.0% Incorrect
Last Solution submitted on Jul 13, 2025

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