Medium data structure and algorithm practice puzzle.
Given how many people reach each stage of a funnel, return the biggest drop between two stages in a row. Compare each stage with the next one and keep the largest difference. So [1000, 800, 200, 150] has drops of 200, 600, and 50, and the answer is 600. One pass, neighbors only.
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 Order Range Service, a pipeline you can run and download. See every Software Engineer project.
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