Medium data structure and algorithm practice puzzle.
Given a number from 0 to 255, reverse the order of its 8 bits and return the result. So 1 (00000001) becomes 128 (10000000). Do this 8 times: shift your result left, add the input's last bit, then shift the input right. Network chips do this all day, because some send a byte's bits in the opposite order.
Solve it three ways: snap the jigsaw pieces together, fill in the blanks, or type it from scratch against the tests. This one is free.
Every line of the solution comes with a note explaining why it is there, and a step by step replay shows the code running. At level 3, where you type it yourself, you can ask for an AI mock interview on this problem that ends with a hiring manager's scorecard.
Then grow it into a real project with the Software Engineer button: this puzzle becomes the Track Flag Store, a pipeline you can run and download. See every Software Engineer project.
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