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PROJECT EULER · #0877

XOR-Equation A

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We use xy for the bitwise XOR of x and y.
Define the XOR-product of x and y, denoted by xy, similar to a long multiplication in base 2, except that the intermediate results are XORed instead of the usual integer addition.

For example, 73=9, or in base 2, 1112112=10012:

11111121111112111111211111291110012
We consider the equation:
(aa)(2ab)(bb)=5
For example, (a,b)=(3,6) is a solution.

Let X(N) be the XOR of the b values for all solutions to this equation satisfying 0abN.
You are given X(10)=5.

Find X(1018).

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