Algorithm
Problem link- https://www.spoj.com/problems/BEENUMS/
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
Code Examples
#1 Code Example with C++ Programming
Code -
C++ Programming
#include <iostream>
#include <cstdio>
#include <vector>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <sstream>
#include <map>
using namespace std;
int main(){
long long int t=0;
while(true){
cin>>t;
if(t==1){cout<<"Y"<<endl;continue;}
if(t==-1)break;
t-=1;
for(int i=1;;i++){
t-=i*6;
if(t==0){
cout<<"Y"<<endl;
break;
}
if(t<0>{
cout<<"N"<<endl;
break;
}
}
}
return 0;
}Input
1
7
19
15
-1
Output
Y
Y
Y
N
Demonstration
SPOJ Solution-Beehive Numbers-Solution in C, C++, Java, Python