Easy data structure and algorithm practice puzzle.
Given the bytes of an integer in the order they sit in memory and whether the machine is little endian, return the integer. Big endian stores the most significant byte first, the way we write numbers; little endian stores the least significant byte first, which is what x86 and ARM do. The same four bytes are a different number depending on which end you start from, and that is the bug in every file format and network protocol that forgot to say.
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.
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