Implement it on LeetCode. The proof of correctness: by always moving the shorter pointer, you never skip a potentially optimal pair. If you skipped the shorter line, it couldn't have formed a larger area anyway (it was the limiting factor). This is a classic example of the greedy two-pointer technique.
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$ curl repovive.com/roadmaps/maang-interview-prep/two-pointers-sliding-window/container-with-most-water-implementation
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