BEENUMS - Beehive Numbers

no tags 

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.

Input

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.

Output

For each test case, output a single line containing an uppercase “Y” if N is a beehive
number, or an uppercase “N” otherwise.

Example

Input:
43
1
7
19
15
-1
Output:
N
Y
Y
Y
N

hide comments
holmesherlock: 2017-01-18 14:33:03

I guess there is some problem with the problem statement,,but after some description in the comment section it is easy to solve..

Last edit: 2017-01-18 14:33:28
scorpion_ajay: 2017-01-11 16:03:38

a piece of cake :p

imperfectboy: 2017-01-07 08:27:29

one of the easiest problem :D Don't think too much !!!

srihari_v: 2017-01-04 19:53:49

my 26th

esshuvo: 2016-12-16 11:17:24

Most confusing problem ever i have solved!Though i solved this using binary search,but till now didn't get this what problem setter said by this " 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.".If anyone please explain this,i will be very thankfull to him :)

spartax: 2016-12-06 22:30:34

See the sequence 1, 1 + 6, 1 + 6 + 12, ... and you will get the solution

Simran Saha: 2016-11-18 08:03:47

I am having difficulty in understanding the problem. Can anybody give a better explanation?

epsilonalpha: 2016-11-03 02:38:34

48th :)
Very simple, AC in one go, 0 sec.

narutohokage_1: 2016-10-23 08:55:29

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.

angel_of_death: 2016-10-21 19:32:12

Was printing something out to debug the code and forgot to comment it out before submitting. Resulted in multiple WA. FML!


Added by:Pablo Ariel Heiber
Date:2010-09-26
Time limit:0.666s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: NODEJS objc VB.net
Resource:FCEyN UBA ICPC Selection 2010