cc.redberry.core.combinatorics

Class Combinatorics

java.lang.Object

cc.redberry.core.combinatorics.Combinatorics

public final class Combinatorics
extends java.lang.Object

This class provides factory and utility methods for combinatorics infrastructure.

Since:

1.0

Method Summary

Modifier and Type	Method and Description
static IntCombinatorialGenerator	createIntGenerator(int n, int k) Returns an IntCombinatorialGenerator object, which allows to iterate over all possible unique combinations with permutations (i.e.

Methods inherited from class java.lang.Object

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

Method Detail

createIntGenerator

public static IntCombinatorialGenerator createIntGenerator(int n,
                                                           int k)

Returns an IntCombinatorialGenerator object, which allows to iterate over all possible unique combinations with permutations (i.e. {0,1} and {1,0} both appears for k=2) of k numbers, which can be chosen from the set of n numbers, numbered in the order 0,1,2,...,n. The total number of such combinations will be n!/(n-k)!.

For example, for k=2 and n=3, this method will produce an iterator over the following arrays: [0,1], [1,0], [0,2], [2,0], [1,2], [2,1].

Parameters:

n - number of elements in the set

k - sample size

Returns:

an iterator over all combinations (with permutations) to choose k numbers from n numbers.

See Also:

IntCombinatorialGenerator