org.paukov.combinatorics3.PermutationGenerator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of combinatoricslib3 Show documentation

Simple java library to generate permutations, combinations and other combinatorial sequences

There is a newer version: 3.4.0

/**
 * Combinatorics Library 3
 * Copyright 2016 Dmytro Paukov [email protected]
 */
package org.paukov.combinatorics3;

import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class PermutationGenerator {

    public enum TreatDuplicatesAs {
        DIFFERENT,
        IDENTICAL
    }

    final Collection originalVector;

    public static   boolean hasDuplicates(Collection collection) {
        if (collection.size() <= 1) {
            return false;
        }
        Set set = new HashSet<>(collection);
        return set.size() < collection.size();
    }

    public PermutationGenerator(Collection originalVector) {
        this.originalVector = originalVector;
    }

    public IGenerator>simple() {
        return new SimplePermutationGenerator<>(originalVector, false);
    }

    public IGenerator> simple(TreatDuplicatesAs treatAsIdentical) {
        return new SimplePermutationGenerator<>(originalVector, TreatDuplicatesAs.IDENTICAL.equals(treatAsIdentical));
    }

    public IGenerator> withRepetitions(int permutationLength) {
        return new PermutationWithRepetitionGenerator<>(originalVector, permutationLength);
    }

}