Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Apache License 

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public class Main {
    public static <T> Collection<List<T>> combinations(List<Collection<T>> domains) {

        List<List<T>> perms = new ArrayList<List<T>>();

        perms.add(new ArrayList<T>());
        addCombination(perms, domains, 0);

        return perms;
    }

    private static <T> void addCombination(List<List<T>> perms, List<Collection<T>> domains, int i) {

        if (i < domains.size()) {

            for (int permIndex = 0; permIndex < perms.size();) {

                List<T> perm = perms.get(permIndex);

                perms.remove(permIndex);

                if (domains.get(i).isEmpty()) {

                    perms.clear();
                    return;
                }

                for (T domValue : domains.get(i)) {

                    List<T> newPerm = new ArrayList<T>(perm);

                    newPerm.add(domValue);
                    perms.add(permIndex++, newPerm);
                }
            }

            addCombination(perms, domains, i + 1);
        }
    }
}