Hard data structure and algorithm practice puzzle.
Given item weights, item values, and a weight limit, return the most value you can carry. Each item is all or nothing. Keep a table where dp[w] is the best value for capacity w. For each item, walk the capacities from high to low and decide whether taking it beats leaving it. Going high to low is what stops you from taking the same item twice.
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 Step Config Explorer, a pipeline you can run and download. See every Software Engineer project.
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