Medium data structure and algorithm practice puzzle.
Given n, return the biggest power of two that's n or less. So 17 gives 16. If n is below 1, return 0. Otherwise, start at 1 and keep doubling while the next double still fits. That's the value of n's highest 1 bit.
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 Flag Store, a pipeline you can run and download. See every Software Engineer project.
Browse all 576 puzzles