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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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2016-02-09 04:51:17
Just by Given TestCases and Brute Force => :) Last edit: 2016-02-09 04:51:57 |
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2016-01-12 09:25:57
pretty simple logic. (4*n-1)/3 is perfect square , its a beehive number. thank you @ashish Last edit: 2016-03-09 16:36:53 |
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2015-12-17 20:49:17 ABHISHEK RAJPUT
construct beehive structure by yourself first...see series,make formula and apply brute force, it will do it. happy coding :) |
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2015-11-25 04:38:52
easy...at every level 6*(n-1) added to next level....brute approach....acptd |
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2015-11-14 06:35:47 sumit suthar
Take it eazy... :) |
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2015-09-22 21:01:28
one line: return rec(n,s+=(*****),i+1); (= Last edit: 2015-09-22 21:02:04 |
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2015-09-12 16:05:55 Abishek
don't think hard ! brute force got accepted ! |
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2015-08-24 11:03:30 Shivam Singh
Level 1 - 1 Level 2 - 7 Level 3 - 19 Level 4 - 37 Level 5 - 61 and so on... seems quadratic a*(h^2)+b*h+c=n ;) |
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2015-08-19 15:49:09 Ashish
N is beehive iff (4N-1)/3 is a perfect square. This problem is pretty shitty. Last edit: 2015-08-19 17:14:05 |
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2015-07-21 18:58:27
this might look awkward, but i used an actual beehive for reference :P |