BEENUMS - Beehive Numbers
A beehive is an enclosed structure in which some honey bee species live and raise their
young. In this problem we consider a two-dimensional sketch of the beehives. Each
beehive is composed of a certain number of cells, where each cell is a regular hexagon.
Each cell may have some neighbors, which are other cells that share a side with that cell.
A cell with exactly 6 neighbors is an internal cell, while a cell with fewer neighbors is an
external one. Notice that an external cell can always be changed to internal by adding
some neighbor cells.
We are interested in a particular class of beehives. This class of valid beehives is defined
recursively as follows: a) a single cell is a valid beehive; and b) given a valid beehive B,
if we add the minimum number of cells such that each external cell of B becomes an
internal cell, the result is a valid beehive.
The number of cells in a valid beehive is called a beehive number. Given an integer N ,
you must decide whether it is a beehive number.
Each test case is described using a single line. The line contains an integer N (1 ≤ N ≤
109 ). The end of input is indicated with a line containing a single −1.
For each test case, output a single line containing an uppercase “Y” if N is a beehive
number, or an uppercase “N” otherwise.
See the sequence 1, 1 + 6, 1 + 6 + 12, ... and you will get the solution
I am having difficulty in understanding the problem. Can anybody give a better explanation?
Do not see comments for hint . Because you can always find a better method , find your own method (Some methods in comment are more time efficient than others so you must try it yourself and then optimize it if it fails) , question is easy . Do not give up and draw diagram for more understanding. Also dont forget it Y and N not Yes and No.
Was printing something out to debug the code and forgot to comment it out before submitting. Resulted in multiple WA. FML!
Very Easy problem if You can observe pattern and apply brute force :) ;)
comment helps a lot but it also destroy the pleasure of problem so please don't post the logic only post hint to that.
long - WA
Solved each query in O(1) with a bit precomputation...