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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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2021-07-30 19:24:01
my 50th :) |
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2021-05-10 06:26:46
Simple question just find the pattern and use roots of a quadratic equation for O(1) soln |
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2021-04-28 06:00:59
use long long. sample cases are correct Last edit: 2021-04-28 06:02:04 |
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2020-09-18 17:34:59
While using binary search take sqrt of n for end :) Last edit: 2020-09-18 17:35:15 |
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2020-04-03 07:10:14
meow |
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2019-12-29 05:35:04
the first line of provided input (43) is wrong; |
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2019-05-18 00:33:43
beautiful question just observe pattern .... 1,1+6,1+6+12,1+6+12+18.... next layer contain 6*lyaer number+prev |
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2018-12-02 10:34:05
My first ever application of Binary Search :) |
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2018-07-26 17:09:25
yo..AC in one go |
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2018-03-28 22:26:16
HINT: SEQUENCES AND SERIES :) |