Medium data structure and algorithm practice puzzle.
Given numRows, return the first numRows rows of Pascal's triangle. Each row starts and ends with 1, and every number in between is the sum of the two numbers above it. Build each row from the one before. It's dynamic programming in its smallest form, and every entry is a count of ways to choose k things from n.
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 Reading Growth Model, a pipeline you can run and download. See every Software Engineer project.
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