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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.
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
Added by: | Pablo Ariel Heiber |
Date: | 2010-09-26 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 NODEJS OBJC VB.NET |
Resource: | FCEyN UBA ICPC Selection 2010 |
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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. |
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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! |
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2016-08-18 15:27:59
Very Easy problem if You can observe pattern and apply brute force :) ;) |
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2016-07-29 08:38:53
comment helps a lot but it also destroy the pleasure of problem so please don't post the logic only post hint to that. |
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2016-07-27 05:08:42 sssymm
@vector1996 touche |
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2016-07-15 20:01:43
long - WA long long - AC |
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2016-07-12 11:38:56 SANDEEP KUMAR
Solved each query in O(1) with a bit precomputation... |
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2016-06-30 17:30:57
Use Long in JAVA, cost me a lot of effort |
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2016-06-22 18:13:54
AC in one GO 1,7,19,37 A(n)th=A(n-1)th+6*(n-1) |
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2016-05-14 21:58:59 Luis Herrera
I used binary search but it looks that there is a simpler solution... |