Medium data structure and algorithm practice puzzle.
Given a list of calls, where a positive number is a call that adds a stack frame of that many bytes and 0 is a return from the latest call, plus a size limit, return the index of the first call that overflows the stack, or -1 if none does. Keep a stack of frame sizes and a running total. A return always frees the newest frame.
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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