Easy data structure and algorithm practice puzzle.
Given n and a secret target between 1 and n, return how many guesses it takes if you always guess the middle of what's left. After each guess, you learn higher or lower and throw away half the range. That's why 20 yes or no questions can cover a million possibilities.
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 Shot Bisector, a pipeline you can run and download. See every Software Engineer project.
Browse all 576 puzzles