Medium data structure and algorithm practice puzzle.
Given a list of rope lengths, join them all into one rope for the lowest total cost. Joining two ropes costs their combined length, and the new rope goes back in the pile. Always join the two shortest ropes. Sort each round to find them, and add up the costs. A min-heap finds the two shortest faster.
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 Ticket Matcher, a pipeline you can run and download. See every Software Engineer project.
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