ASU 406 All Soviet Union MO 1985 no of painted parts by n straight lines
Source:
August 5, 2019
linescombinatorial geometrymaximum
Problem Statement
straight lines are drawn in a plane. They divide the plane onto several parts. Some of the parts are painted.
Not a pair of painted parts has non-zero length common bound. Prove that the number of painted parts is not more than .