Each spectator thought he would get ~K-P+1~ pieces of walnut roll (that is how many pieces there are in total, marked from ~P~ to ~K~). The solution to the first part of the task is therefore determining the maximum value of ~K-P+1~ which we calculate for each spectator individually.

As spectators were taking pieces of the walnut roll, at some point it might have occurred that a spectator could not take a piece that was provided for them because someone else had taken it already. We therefore create an array of a maximum length of ~1000~ where we initialize every element to the value ~1~ (every piece is in its place). For each spectator marked with ~i~, we sum up the values in the array marked from ~P_i~ to ~K_i~; also, in that interval, we change every value ~1~ to ~0~ (the piece is not there anymore). During this procedure, we keep the maximum value of the sum.