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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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2017-12-30 10:00:10
AC in one Go .. :) Just find the formula for it... |
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2017-12-09 18:06:33
take care of -1 at the end of input ac in 2nd go ;p |
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2017-11-29 18:51:20
AC in a go chillar sum da |
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2017-10-05 20:18:10
HINTS:google beehive structure |
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2017-07-18 19:07:06
can be done with binary search |
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2017-05-31 04:27:05 ABHISHEK
If you are using brute force for the obtained pattern than the time complexity is square root n :) |
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2017-05-20 19:02:34
Googled a picture of a beehive to observe the pattern initially! LOL! O(1) solution, though!! |
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2017-04-11 19:13:27
simple!! just find the pattern and check for beehive numbers |
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2017-04-01 05:31:36
AC with Brute Force in 0.00 s. Don't try too hard =) |
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2017-03-11 12:31:05
those who are not able think of direct solution should try binary search |