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/**
* Combinatorics Library
* Copyright 2012 Dmytro Paukov d.paukov@gmail.com
*/
package org.paukov.combinatorics;
import org.paukov.combinatorics.composition.IntegerCompositionGenerator;
import org.paukov.combinatorics.subsets.IntegerSubSetGenerator;
/**
* This is a special factory to create integer vectors and generators.
*
* @author Dmytro Paukov
* @version 2.0
* @see IntegerVector
* @see IntegerGenerator
*/
public class IntegerFactory {
/**
* Creates an empty integer vector instance
*
* @return The empty vector
*/
public static IntegerVector createIntegerVector() {
return new IntegerVector(0);
}
/**
* Creates an empty integer vector instance
*
* @return The empty vector
*/
public static IntegerVector createIntegerVector(int size) {
return new IntegerVector(size);
}
/**
* Creates an integer vector from the given integer array
*
* @param array The array
* @return The integer vector
*/
public static IntegerVector createIntegerVector(int[] array) {
return new IntegerVector(array);
}
/**
* Creates an integer vector from the given integer array by the length
* len
*
* @param array The array
* @param len the length
* @return The integer vector
*/
public static IntegerVector createIntegerVector(int[] array, int len) {
return new IntegerVector(array, len);
}
/**
* Creates a sub-set generator
*
* @param originalVector The initial vector
*/
public static IntegerGenerator createIntegerSubSetGenerator(
IntegerVector originalVector) {
return new IntegerSubSetGenerator(originalVector);
}
/**
* Creates a sub-set generator
*
* @param originalVector The initial vector
* @param treatAsIdentical true if the sub sets have to be treated as identical
* @return An instance of the generator
* @see IntegerSubSetGenerator
*/
public static IntegerGenerator createIntegerSubSetGenerator(
IntegerVector originalVector, boolean treatAsIdentical) {
return new IntegerSubSetGenerator(originalVector, treatAsIdentical);
}
/**
* Creates a composition generator
*
* @param n The initial value
*/
public static IntegerGenerator createIntegerCompositionGenerator(Integer n) {
return new IntegerCompositionGenerator(n);
}
/**
* This method creates a combinatorics vector of (1, 2,.., n)
*
* @param n The value of the number of the elements
* @return The vector
*/
public static IntegerVector range(int n) {
if (n < 0) {
throw new IllegalArgumentException(
"Range value must be more or equal to 0");
}
// If range is zero return an empty vector
if (n == 0) {
return new IntegerVector();
}
int[] array = new int[n];
for (int i = 0; i < n; i++) {
array[i] = i + 1;
}
return new IntegerVector(array);
}
/**
* This method creates a combinatorics vector of (from, from + 1,.., to-1,
* to)
*
* @param from The first value
* @param to The second value
* @return The vector
*/
public static IntegerVector range(int from, int to) {
if (from > to) {
throw new IllegalArgumentException(
"From parameter must be less then To parameter");
}
int[] array = new int[to - from + 1];
for (int i = 0; i < to - from + 1; i++) {
array[i] = i + from;
}
return new IntegerVector(array);
}
}