For checking overlap, if any vertex of rectangle A is within rectangle B then they overlap. If no vertex of A is within B, B might still be entirely contained within A, so check one vertex of B to see if it's within A.

Actually, two rectangles could intersect without any vertex of either box lying inside the other. Picture two rectangles, perpendicular to each other, arranged as a cross.

In reply to Re^2: Sorting hashes... by husker
in thread Sorting hashes... by fiddler42

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