What does the The Gauntlet puzzle teach?
Two walls hold water = width × the shorter wall. Sweep from the widest pair and always move the shorter wall inward — grabbing the two tallest bars ignores width.
Why do interviews ask about this?
Container With Most Water is a canonical interview problem — the O(n) two-pointer beats the obvious O(n²) all-pairs scan, and proving why you always move the shorter wall inward is exactly what interviewers probe.
How is it scored?
The engine computes the provably-optimal answer for the exact instance you played (dynamic programming, shortest-path, or exhaustive search — never a heuristic) and scores your attempt as a percentage of it. No login needed to see your score.