org.whaka.util

Class UberMath

java.lang.Object

org.whaka.util.UberMath

public class UberMath
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
UberMath()

Method Summary

Modifier and Type	Method and Description
static int	nChooseK(int n, int k) Calculate binomial coefficient for the specified n and k.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

UberMath

public UberMath()

Method Detail

nChooseK

public static int nChooseK(int n,
                           int k)

Calculate binomial coefficient for the specified n and k.

In other words, for a set of specified size n method calculates number of possible distinct combinations of the specified size k.

Example, in the set [a, b, c] of size 3 - there're 3 possible combinations of size 2:

• a, b
• a, c
• b, c

Or one possible combination, of size 3:

• a, b, c

Note:

        
If k = 0             method returns 1 for any n
        
If k = 1             method returns n for any n > 0
        
If k = (n-1)         method returns n for any n > 0
        
If k = n             method returns 1 for any n
 

Parameters:

n - - size of a set. Required positive.

k - - size of a combination. Required to be >= 0 and <= n.