Medium data structure and algorithm practice puzzle.
Given two sorted arrays, return the values that are in both, with no repeats. Put a pointer at the start of each. If the values match, keep it (unless you just kept it) and move both. Otherwise, move the pointer on the smaller value. It's the merge step from merge sort, keeping only the matches.
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 Request Throttle, a pipeline you can run and download. See every Software Engineer project.
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