PACTF_2017: Zeroes and Ones
Category: Points: 30 Description:
Bit String Flicking How many solutions are there for X in the expression: LCIRC -3 (01011 AND X OR 10100) = 01101
Hint:
Try simplifying it?
Write-up
Simplification of strings!
LCIRC -3 (01011 AND X OR 10100) = 01101
Since LCIRC refers to circulating bits to the left, we have to recirculate to the right by 3.
(01011 AND X OR 10100) = 10101
Now, to solve for permutations of x, we need to see which bits can be changed without affected the results.
(01011 AND XXXXX OR 10100) = 10101
^ ^
As two bits can be changed, total solutions equals 2*2
Therefore, the flag is 4
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