2016 costumers in a shop on a particular day, maximal wanted
Source: Balkan BMO Shortlist 2016 C2
July 30, 2019
combinatoricsMaximal
Problem Statement
There are costumers who entered a shop on a particular day. Every customer entered the shop exactly once. (i.e. the customer entered the shop, stayed there for some time and then left the shop without returning back.)
Find the maximal such that the following holds:
There are customers such that either all of them were in the shop at a speci c time instance or no two of them were both in the shop at any time instance.